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  • Artikel: DFG Deutsche Nationallizenzen  (435)
  • 1980-1984
  • 1975-1979  (435)
  • 1978  (435)
  • Chemical Engineering  (394)
  • pharmacokinetics
Datenquelle
  • Artikel: DFG Deutsche Nationallizenzen  (435)
Materialart
Erscheinungszeitraum
  • 1980-1984
  • 1975-1979  (435)
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 275-284 
    ISSN: 1432-1041
    Schlagwort(e): Diazepam ; pharmacokinetics ; pregnant women ; plasma clearance ; blood/plasma concentration ratio ; placental transfer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The disposition of diazepam has been studied in pregnant women at parturition. The plasma concentration of diazepam was monitored for at least 3 days in 18 women who received a single intravenous injection of 10 mg during the 10 h-period prior to delivery. Fourteen mothers had uneventful puerperia (Group I) and in 13 of these cases there was a pronounced postnatal increase in the plasma concentration of diazepam. The terminal phase half-life (t1/2) was significantly greater for Group I (mean = 65 h; range = 24–114 h) than for age-matched non-pregnant patients (mean = 29 h; range = 18–44 h from literature). The prolonged t1/2 appeared to be related to changes in the distribution of diazepam and not to a reduction in hepatic elimination since the total plasma clearance (Cltp) in these 14 pregnant patients (mean = 28 ml/min; range = 18–43 ml/min) was not reduced compared to that reported for non-pregnant controls (mean = 30 ml/min; range = 22–45 ml/min). Four mothers underwent postnatal surgery for tubal ligation (Group II) and the plasma concentration-time profiles for this group did not show the same postnatal phenomenon as did the profiles obtained for Group I. The t1/2 for Group II was shorter (mean = 31 h; range = 24–37 h) than for Group I and similar to that for the non-pregnant controls. The Cltp for Group II was greater (mean = 56 ml/min; range = 48–63 ml/min) than for both Group I and non-pregnant controls. These results suggest that delivery alters the disposition of diazepam and is generally associated with a postnatal re-distribution of diazepam into the systemic circulation. The blood/plasma concentration ratio was determined in 9 patients (mean = 0.62; range = 0.54–0.77). There was no difference in the total blood clearance between the pregnant patients of Group I and the non-pregnant controls. In most cases the umbilical venous plasma concentration (Cpuv) of diazepam was greater than the peripheral maternal venous plasma concentration (Cpmv) at delivery. The foetus appears to constitute a slowly equilibrating tissue-group in which diazepam does not reach equilibrium with the maternal systemic circulation for at least 5–10 h at which time the diazepam concentration in maternal and foetal plasma is similar.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 49-53 
    ISSN: 1432-1041
    Schlagwort(e): p-Chlorophenoxyisobutyric acid ; clofibrate ; steady-state plasma concentrations ; bioavailability ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Plasma concentrations and bioavailability of clofibrinic acid have been estimated under conditions approaching the steady-state during a ten-day period of administration as clofibrate or as a calcium clofibrinate-carbonate combination (1:1 w/w) at a dosage interval of 12 h. Formulation — related differences in bioavailability were not significant, and the 95% confidence limits of these differences were within −2% to +8% of the mean for the reference formulation of clofibrate. The mean steadystate plasma concentrations of clofibrinic acid measured on the tenth day of dosing were 116 µg/ml±22 S.D. and 119 µg/ml±23 S.D. after administration of 885 mg as clofibrate and the calcium clofibrinate-carbonate combination respectively. The peaks of mean plasma concentrations were 70 µg/ml±15 S.D., 119 µg/ml±32 S.D. and 131 µg/ml±26 S.D. on the first, fifth and tenth day of dosing with clofibrate, and 62 µg/ml±13 S.D., 127 µg/ml±S.D. and 143 µg/ml±25 S.D. on the corresponding days of dosing with the calcium clofibrinate-carbonate combination. After the last dose on the tenth day of dosing, the mean apparent half-lives of elimination of clofibrinic acid from plasma were 24.2 h±4.4 S.D. and 25.5 h±3.2 S.D. after administration of clofibrate and the calcium clofibrinate-carbonate combination respectively.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 69-72 
    ISSN: 1432-1041
    Schlagwort(e): Phenazone ; pharmacokinetics ; hydrocortisone ; elimination rate ; distribution volume
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The influence of a high plasma concentration of hydrocortisone on the metabolism of phenazone in humans has been studied. Two series of experiments were carried out, Group A to demonstrate any enzyme-inducing effect of hydrocortisone, and Group B to study the immediate effect of hydrocortisone on the metabolism of phenazone. 9 subjects (Group A) received a total 250–400 mg hydrocortisone i.m. twice daily for three days and the 24-hour elimination of phenazone was studied before and afterwards. In a further 5 subjects (Group B) the elimination of phenazone was examined during administration of hydrocortisone or placebo. The elimination rate and the apparent volume of distribution of phenazone remained unchanged under both experimental conditions.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 97-101 
    ISSN: 1432-1041
    Schlagwort(e): Clonidine ; plasma level ; pharmacokinetics ; steady state ; urinary excretion ; side-effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A single oral dose of clonidine 300 µg was administered to 8 healthy, normotensive subjects and the time course of its plasma concentrations was followed for 24 h. The plasma concentration of clonidine rose to a peak of 1.17±0.12 ng/ml at about 2 h: the absorption half-life was 0.6±0.2 h. Elimination followed first order kinetics with a half-life of 7.7±2.0 h. The correlation between the two most common side-effects of clonidine, sedation and dryness of the mouth, with the time course of its plasma concentrations was highly significant, p〈0.01. All the subjects complained of severe sedation. During continuous administration of clonidine (75 µg t.i.d.) for one week a steady state serum level of 0.30–0.35 ng/ml was achieved. One 75 µg tablet of clonidine raised the serum level to about 0.69±0.13 ng/ml in two hours. After cessation of dosing, the serum level declined with a half-life of 7.5±1.5 h. The urinary excretion of unchanged clonidine was found to be about onethird of the administered dose in 24 h during continuous administration and in the first 24 h after the single oral dose.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 203-212 
    ISSN: 1432-1041
    Schlagwort(e): Mepivacaine ; pharmacokinetics ; neonates ; healthy adults ; metabolism ; renal excretion ; lignocaine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics and metabolism of mepivacaine has been studied in premature neonates dosed subcutaneously and in healthy adults dosed intravenously. The pharmacokinetics of mepivacaine in four neonates (N) was compared with that in six adults (A). Newborns had a significantly longer terminal phase half-life than adults (N mean 8.69 h; A mean 3.17 h). Total plasma clearance normalized on body weight was significantly smaller in neonates (mean 2.34 ml/min/kg) than in adults (mean 5.47 ml/min/kg), as was the hepatic blood clearance (N mean 1.37 ml/min/kg; A mean 5.10 ml/min/kg). The renal plasma clearance, however, was significantly greater in neonates (mean 0.76 ml/min/kg) than adults (mean 0.20 ml/min/kg). There was an average six-fold increase in the fraction of the dose excreted unchanged in newborns (mean 43.3%) compared to adults (mean 7.1%) with acidified urine (pH 5.5–6.0). There was significantly more of the mono-N-demethylated metabolite of mepivacaine excreted by newborns (mean 11.4%) than by adults (mean 2.2%), but their capacity to carry out aromatic hydroxylation of mepivacaine was negligible. These results for mepivacaine were compared with those previously reported for lignocaine in premature infants. The immaturity of hepatic function appears to have diminished more profoundly the ability of premature infants to metabolize mepivacaine than lignocaine. These findings are discussed in terms of perfusion theory of hepatic drug elimination.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 143-147 
    ISSN: 1432-1041
    Schlagwort(e): Children ; leukemia ; high-dose methotrexate ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of intravenous high-dose methotrexate were studied in two groups of children being treated for malignant diseases, mostly acute lymphatic leukemia. The peak serum level of methotrexate of 2.32·10−5 mol/l was found in children given 500 mg methotrexate/m2 by a 24 h infusion, and another group given 2790 mg/m2 during a 6 h infusion had serum levels as high as 2.16·10−4 mol/l. The decay of serum concentration of methotrexate after completion of the infusion followed a diphasic curve, with an initial serum half-life of 4.8 h, followed by a second half-life of 34.4 h at distribution equilibrium. The apparent volume of distribution was 56.8 litres/m2. Significant levels of methotrexate were found in cerebrospinal fluid, but penetration into cerebrospinal fluid was slow. Urinary excretion of methotrexate was considerable. Four to five days after commencement of the infusion, urinary concentrations of methotrexate still exceeded the serum levels.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 335-340 
    ISSN: 1432-1041
    Schlagwort(e): Drug binding to muscle ; interindividual differences ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Binding of 22 drugs to human muscle tissue has been determined by ultrafiltration. All drugs tested were bound, the bound fraction ranging from 13% (aminophenazone) to 〉98% (desipramine). Both linear and nonlinear binding was observed. For chemically related substances, binding to muscle tissue correlated with plasma binding and lipid solubility. There were significant differences in binding to muscle from different individuals. With respect to pharmacokinetics of drugs, it is suggested that binding to muscle tissue may be at least as important as plasma binding.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 41-48 
    ISSN: 1432-1041
    Schlagwort(e): Furosemide ; pharmacokinetics ; anephric patients ; metabolism ; protein binding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of furosemide 40 mg i.v. were compared in 7 anephric patients and in 7 normal subjects. The average serum clearance was 66 ml/min in the patients and 219 ml/min in the normal subjects, and the corresponding weight corrected clearances were 1.33 ml/min · kg and 2.96 ml/min · kg. Binding to serum proteins was significantly decreased in the anephric subjects, in whom a significant negative correlation was found between the percentage binding and the volume of distribution VDss. In the patients, but not in the normal subjects, there was a significant positive correlation between $$V_{D_{ss} } $$ and serum clearance. Both in normal and anephric individuals 4-chlor-5-sulphamoylanthranilic-acid (CSA) was found, but there was no evidence of special accumulation either of CSA or anthranilic acid in the anephric patients. In the patients the initial increase in serum concentration of sodium and protein followed by a more conspicuous decrease were more pronounced, but none of the changes were statistically significant.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 29-33 
    ISSN: 1432-1041
    Schlagwort(e): Microcrystalline theophylline ; chronic obstructive airways disease ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Plasma theophylline concentrations have been measured in 9 patients with chronic obstructive airways disease following the oral administration of a microcrystalline theophylline preparation. Some measurements of FEV1 were also made. Four patients were given 375 mg as a single dose and then subsequently 375 mg stat and 125 mg 4 times daily for 3 days, (Group I). A further 5 patients took 250 mg as a single dose and then 250 mg 4 times daily for 3 days, (Group II). In both groups, following the single dose and again after the last dose of chronic administration, blood samples were obtained at frequent intervals up to 24 h for plasma drug estimation. During the 3-day course, blood samples were drawn before and 2 h after each morning dose. In Group I patients, substantial plasma theophylline concentrations were seen only after the loading dose. Thereafter, the mean concentrations before or 2 h after the morning doese were always less than 4.0 µg/ml. Trough concentrations were usually below 2.0 µg/ml. In contrast patients in Group II achieved substantially higher plasma theophylline concentrations, with mean peak concentrations always 10 µg/ml or greater, and trough concentrations greater than 5 µg/ml on at least one occasion in every subject. The elimination half-lives after chronic administration in both groups were not significantly different from those obtained after single doses. Mean drug accumulation, measured as AUCss/AUC1, was 0.87±0.07 in Group I and 0.72±0.14 in Group II, indicating that accumulation had not occurred with either regimen. The mean increase in FEV1 2 h after the administration of a single dose was 19.2% after 375 mg and 16.7% after 250 mg. These results indicate that the recommended dosage regimen for microcrystalline theophylline preparation (375 mg stat and 125 mg 4 times daily) produces inadequate plasma theophylline concentrations: 250 mg 4 times daily would appear to be likely to result in satisfactory theophylline levels in more patients.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 365-371 
    ISSN: 1432-1041
    Schlagwort(e): Etidocaine ; pharmacokinetics ; metabolism ; neonate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The urinary elimination of etidocaine and several of its metabolites was investigated in neonates whose mothers had received one or more doses of etidocaine during labour. The urine collection period ranged among the neonates from 21.4 to 47.0 h post-partum. The total amounts of etidocaine and its metabolites recovered in neonatal urine represented a mean of 0.12 per cent of the maternal dose. Some differences in the pattern of urinary metabolites were observed between neonates and adults. Mean half-life of elimination of etidocaine calculated from sigma-minus plots of the neonatal urinary data was 6.42 h. This is greater than that previously reported following intravenous administration of etidocaine to adults (2.6 h). The slower rate of elimination in neonates is probably due to an increased neonatal volume of distribution since there is evidence to show that etidocaine is extensively metabolised by the neonate.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 379-383 
    ISSN: 1432-1041
    Schlagwort(e): Antipyrine ; pharmacokinetics ; phenzone ; posture ; immobilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of a single dose of phenazone was studied in six subjects while ambulant and during bed rest for 3 days. Elimination of the drug was followed for 12 h after oral and intravenous administration. The elimination rate constant and total body clearance were significantly increased during bed rest as compared to the ambulant period, but the differences were small. The apparent volume of distribution decreased significantly. No consistent change due to bed rest was found in the rate of absorption or bioavailability of the oral dose.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 209-212 
    ISSN: 1432-1041
    Schlagwort(e): Paracetamol ; acetaminophen ; Gilbert's syndrome ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of paracetamol after intravenous and oral administration has been studied in 6 patients with Gilbert's syndrome, and 6 healthy controls. Paracetamol clearance was significantly less in the patients (255 ml/min SE±23 ml/min) than in the normal subjects (352 ml/min SE±40 ml/min). Moreover, whilst paracetamol concentrations declined monoexponentially in the patients, the decline was biexponential in the controls. No difference in the bioavailability of 500 mg paracetamol given orally was observed between the two groups. The results suggest that not only is paracetamol elimination impaired in Gilbert's syndrome, but that its distribution kinetics are also abnormal. Both these findings could be attributed to a decrease in hepatic glucuronyl transferase activity.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1432-1041
    Schlagwort(e): Aminopyrine ; pharmacokinetics ; 14CO2 breath test ; hepatic disease
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The time-course of aminopyrine in plasma and of14CO2 in breath was determined for 6 hours after oral administration of (14C-methyl) aminopyrine to healthy controls and to patients with hepatitis and hepatic fibrosis, cirrhosis and hepatic bilharziasis.14CO2 in breath declined about 1.8 times more slowly than aminopyrine plasma levels, which suggests the occurrence of metabolite demethylation. This was confirmed by the slow elimination of14C from plasma, the formation of14CO2 after aminopyrine had disappeared and the presence of a considerable amount of monomethyl-aminopyrine in plasma. The mean14CO2 concentration in breath was correlated with but was not proportional to aminopyrine clearance, which was attributed to individual differences in aminopyrine half-life. Both a correlation and proportionality were found when14CO2 extrapolated to zero time was used as a parameter of14CO2 production. Hepatic disease affected aminopyrine clearance to a variable extent. In the hepatitis and fibrosis group, aminopyrine clearance was affected in 2 out of five subjects. In all except one cirrhotic subject aminopyrine clearance was markedly decreased. Moreover, in three out of seven cases aminopyrine absorption was impaired, presumably due to decreased gastrointestinal blood-flow. This may produce an erroneously low14CO2 concentration in breath during the first two hours after aminopyrine administration. Hepatic bilharziasis was accompanied by very low aminopyrine clearance in all four cases. In two patients high apparent Vd values were observed, probably due to “first-pass” metabolism. Patients with ascites had Vd values within normal limits.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 57-67 
    ISSN: 1432-1041
    Schlagwort(e): Chemotherapy ; sulfadiazine ; trimethoprim ; pharmacokinetics ; acetylation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Sulfadiazine (SDZ) 800 mg and trimethoprim (TMP) 160 mg were given orally to 10 normal subjects and the concentration of SDZ and TMP in serum and urine was followed for 24 h. Both drugs showed a significant negative correlation between individual “peak” concentrations in serum and the body weight of the subject. Twelve hours after dosing the serum concentration was 12 to 25 µg/ml for SDZ and 0.3 to 1.1 µg/ml for TMP. Individual concentration ratios between SDZ and TMP in serum were 4.8 (1 h) – 145 (24 h), and in the urine the ratio was close to 6 throughout the 24 h collection period. The range of urinary concentrations was from 65 to 400 µg/ml for SDZ and from 13.8 to 93.4 µg/ml for TMP. The fraction acetylated SDZ/acetylated SDZ + SDZ was 21% during the 0–8 h period, 33% during the 8–15 h period and 41% during the 15–24 period. The average values for the notional volume of distribution, Vd, were 0.36±0.13 1/kg for SDZ and 1.39±0.25 1/kg for TMP. The average “t1/2” was 15.2±7.4 h for SDZ and 7.4±1.9 h for TMP. Individual subjects showed a significant correlation between the serum clearance of TMP and SDZ (p〈0.01) and also between the renal clearance of the two drugs (p〈0.05). The serum clearance was significantly correlated with the renal clearance for TMP but not for SDZ. For SDZ Vd was significantly negatively correlated with the elimination constant; for TMP no such correlation was found. The serum clearance of SDZ was significantly correlated with the percentage of SDZ which was excreted as the (presumably) acetylated compound. The renal clearance of SDZ was independent of the serum concentration of SDZ. There was a highly significant negative correlation between the renal clearance and serum concentration of TMP, as well as for “acetylated SDZ”. The renal clearance of “acetylated SDZ” averaged more than six times that of unconjugated SDZ. With increased urine flow the renal clearances of TMP and SDZ were significantly increased.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 237-244 
    ISSN: 1432-1041
    Schlagwort(e): Furosemide ; arterial hypertension ; protein binding ; sodium excretion ; renal function ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Furosemide 40 mg was injected intravenously in 7 patients with severe hypertension and vascular complications. A two compartment, open model was used to describe the disappearance of the drug from serum. The mean serum clearance (Cls=1.83 ml/min · kg) was significantly reduced compared to the mean Cls-value of a group of normals (2.96 ml/min · kg). A significant correlation was found between Cls and mean blood pressure, as well as between Cls and renal clearance (mean Clr=0.83 ml/min · kg); extrapolation of the regression line yielded a Cls-value of 50 ml/min for Clr=0. The Clr was also significantly negatively correlated with mean blood pressure. Protein binding of furosemide was normal, except in one patient, who had considerable impairment of renal function. Apparently more than 90% of unchanged furosemide passed in urine was excreted by tubular transport. A highly significant negative correlation was found between Cls and the fraction of furosemide excreted as a glucuronide. During the first two hours, significantly less sodium was excreted by the patients than by a comparable group of normal subjects. The correlation between serum concentration of furosemide and the amount excreted of sodium was not significant, but highly significant correlations were found between the amounts of furosemide and sodium excreted by the kidney in 0–30 and 0–60 min. In all the individual patients an approximately linear relationship with wide variation in the slope was found between the cumulative excretion of furosemide and sodium from 0–30 min to 0–60 and to 0–120 min. After 120 min deviations were observed in the curves from 4 of the patients, which indicated that smaller and smaller additional amounts of sodium were excreted with constant additional amounts of furosemide.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 267-271 
    ISSN: 1432-1041
    Schlagwort(e): Lithium ; sustained-release ; pharmacokinetics ; manic patients
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary An ordinary and a sustained-release lithium carbonate preparation were administered acutely at equivalent dosage (1.80 g=24.3 mmol) in a crossover fashion to manic patients. Serum lithium levels were determined by atomic absorption spectroscopy and pharmacokinetic parameters were calculated. Maximum mean serum levels of 1.13 mmol/l and 0.78 mmol/l were achieved at 6 h and 12 h respectively with the ordinary and sustained-release forms. The mean half-lives of absorption, redistribution and elimination were 0.78 h±0.05 (SE), 5.06 h±0.23, 26.8 h±4.5 and 3.73 h±0.37 (SE), 4.42 h±0.28 and 25.6 h±5.5 for the ordinary and sustained-release forms respectively. In healthy volunteers the ordinary preparation was completely absorbed but only 85% of the sustained-release form was absorbed in the manic subjects. Lithium ion distributed into two kinetic compartments and the final compartment appeared to correspond to total body water.
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 277-280 
    ISSN: 1432-1041
    Schlagwort(e): Doxycycline ; iron ; charcoal ; enteral cycling ; man ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In order to study the intestinal interactions of doxycycline (DC) with Fe++ and charcoal, two groups of healthy volunteers were given either 200 mg or 100 mg DC in capsules at 2 p. m. and 9 p. m., and blood samples for fluorimetric assay of DC were collected for 24 h starting at 8.30 a. m. on the following morning. A 24-h-urine was also collected. The test was subsequently repeated at one-week intervals, when the volunteers also ingested either ferrous sulphate (80 mg Fe++) or charcoal (4.0 g) immediately after the zero-time sample of DC and at 3, 8 and 12 h. Charcoal completely adsorbed DC in vitro in an artificial small intestinal fluid. Ferrous sulphate or charcoal did not modify the serum level or urinary excretion of DC after the 200 mg+200 mg dose, but ferrous sulphate did reduce the 24-h urinary excretion of DC after the 100 mg+100 mg dose. The serum half-life and AUC of DC were reduced by ferrous sulphate given after the 100 mg+100 mg dose of DC. Charcoal did not modify any parameter, even after the 100 mg+100 mg dose of DC. The results do not support existence of important enteral cycling of DC. Although oral ferrous sulphate can lower the serum level and shorten the serum half-life of DC, the acute experiment suggested that a therapeutic serum level of DC can be maintained despite treatment with iron in the doses used in iron-deficiency, and charcoal in the doses used in diarrhoeic states, if the drugs are administered several hours apart.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 69-73 
    ISSN: 1432-1041
    Schlagwort(e): Citalopram ; pharmacokinetics ; man ; steady state levels ; metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma concentrations of citalopram, a potent serotonin reuptake inhibitor, and its demethylated metabolite have been determined by a specific fluorescence coupling technique during single dose experiments in volunteers and in clinical tests. Citalopram was found to have linear kinetics within the dose range investigated, which were characterized by fairly rapid absorption and slow elimination (biological half-life 1–21/2 days). Steady state levels in the range 120–340 nM (i.e. slightly above those associated with pharmacodynamic activity in animals) were attained within a week. A drug/metabolite ratio of 2–3 was recorded.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 431-434 
    ISSN: 1432-1041
    Schlagwort(e): Timolol ; pharmacokinetics ; oral and intravenous dosing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma kinetics of timolol administered orally and intravenously to 5 male subjects were examined. Bioavailability was reduced by 25% when the drug was taken orally. Mean plasma half-life after oral dosing was 4.86 h, and after intravenous administration it was 4.56 h; the difference was not significant. The volume of distribution was 3.5 l/k. It is suggested that timolol is little affected by the ‘first pass effect’, even though there is marked interindividual variation in availability and peak plasma level.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 143-152 
    ISSN: 1432-1041
    Schlagwort(e): Lignocaine ; pharmacokinetics ; neonates ; metabolism ; renal excretion ; plasma concentrations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics and metabolism of lignocaine in premature neonates was studied after subcutaneous administration. The collection of serial urine together with a limited number of blood samples from neonates enabled simultaneous computer fitting of data to a pharmacokinetic model. The disposition kinetics of lignocaine in four neonates were compared with similar data reported for adults. Neonates had prolonged t1/2 (neonate mean: 3.16 h; adult mean: 1.80 h), and an increased total volume of distribution (neonate mean: 2.75 l/kg; adult mean: 1.11 l/kg) compared with adults. Total plasma clearance (Cltp) normalised on body weight showed no significant difference between neonates (mean: 0.610 l/h/kg) and adults (mean: 0.550 l/h/kg). The urinary excretion of lignocaine and several of its metabolites was studied in 8 neonates and 11 adults. Neonates were shown to excrete much more unchanged lignocaine (mean: 19.67%) compared with adults (mean: 4.27%) and the proportion of the dose excreted as 4-hydroxyxylidine is considerably reduced in neonates (neonate mean: 8.89%; adult mean: 63.78%). The use of the two pharmacokinetic parameters, t1/2 and Cltp, as indices of drug elimination ability are discussed.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 219-222 
    ISSN: 1432-1041
    Schlagwort(e): Glaziovine ; pharmacokinetics ; plasma levels ; urinary excretion ; biliary excretion ; enteral absorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetic parameters of Glaziovine, a pro-aporphine alkaloid with neuropharmacological properties, were investigated in healthy human volunteers. Glaziovine-14C 20 mg was administered in capsules (oral route) and in vials (i.v. route). Total radioactivity was measured in plasma, urine and faeces. When administered orally, peak plasma levels were encountered at 2 h. The cumulative urinary excretion of total radioactivity over a 24 h period was 38% after oral and 50% after i.v. administration. Investigation of metabolites in urine revealed Glaziovine glucuronide as the sole metabolite of the drug. By comparing the percentage of urinary excretion or the area under the plasma level-time curve (AUC) obtained in the first 24 hours after i.v. and oral administration, enteral absorption was found to range from 78 to 84%. Thus, glaziovine appears to show very high enteral absorption.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 55-60 
    ISSN: 1432-1041
    Schlagwort(e): Valproic acid ; pharmacokinetics ; liver disease
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The disposition of valproic acid (di-n-propylacetate; VA) has been studied after a single oral dose of a solution of 450 mg in 7 patients with alcoholic cirrhosis and in 4 patients recovering from acute hepatitis. The diagnosis was based on biochemical function tests and histological findings. The pharmacokinetic parameters were compared with those reported for healthy volunteers. VA in therapeutic concentration (80 µg/ml) in plasma was less bound to plasma proteins in patients with alcoholic cirrhosis (70.7±11.3%) and in patients recovering from acute hepatitis (78.1±14.1%) than in controls (88.7±5.2%). The reduced binding affected the blood/plasma concentration ratio and the apparent distribution volume Vd(β); the latter was increased from the normal value of 0.14±0.05 l/kg to 0.22±0.09 (p〈0.05) in alcoholic cirrhotics, and to 0.20±0.07 (p=0.056) in patients recovering from acute hepatitis. The half-life of elimination T1/2 (β) (controls=12.2±3.7 h) was significantly (p〈0.05) prolonged in cirrhotics (18.9±5.1 h) and in patients recovering from acute hepatitis (17.0±3.7 h). The plasma $$\overline {Cl} $$ of total drug was not impaired, which can best be explained by the lower plasma protein binding, which might have increased the $$\overline {Cl} $$ of this drug which shows restricted clearance. In addition, the plasma $$\overline {Cl} $$ of free drug was significantly (p〈0.02) reduced in alcoholic cirrhotics. During a two day urine collection no measurable amount of unchanged VA was recovered. There was considerable excretion of VA-conjugates, which could be hydrolyzed either by HCl or by β-glucuronidase/arylsulphatase (4–23% of the dose). These percentages were in the same range as in normals (26.7±16.1%). The study indicates that elimination of VA is slightly impaired in patients with dysfunction of the liver.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 267-274 
    ISSN: 1432-1041
    Schlagwort(e): Chlordiazepoxide ; benzodiazepines ; pharmacokinetics ; bioavailability ; intramuscular injection ; alcohol withdrawal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The absorption of oral and intramuscular (i. m.) chlordiazepoxide hydrochloride (CDX · HCl) was compared in two pharmacokinetic studies. In Study One, single 50-mg doses of CDX · HCl were administered orally and by i. m. injection to 14 healthy volunteers using a crossover design. Whole-blood concentrations of chlordiazepoxide (CDX) and its first active metabolite, desmethylchlordiazepoxide (DMCDX), were determined in multiple samples drawn after the dose. Mean pharmacokinetic variables for CDX following oral and i. m. administration, respectively, were: highest measured blood concentration, 1.65 vs 0.87 µg/ml (p〈0.001); time of highest concentration, 2.3 vs 7.6 h after dosing (p〈0.001); apparent absorption half-life, 0.71 vs 3.39 h (p〈0.001). Biphasic absorption after i. m. injection, consistent with precipitation at the injection site, was observed in 9 of 14 subjects. Based upon comparison with previous intravenous data, the completeness of absorption was 100% for oral vs 86% for i. m. CDX · HCl (p〈0.1). In Study Two, 28 male chronic alcoholics with clinical manifestations of the acute alcohol withdrawal syndrome were randomly assigned to one of four treatment conditions: 50 or 100 mg doses of CDX · HCl, by mouth or by i. m. injection. Concentrations of CDX and DMCDX, determined in plasma samples drawn every 20 min for 5 h following the dose, were significantly higher after oral administration of a given dose than at corresponding points in time after i.m. injection after the same dose. Thus absorption of oral CDX is reasonably rapid and complete, whereas the absorption rate of i. m. CDX is slow.
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  • 24
    ISSN: 1432-1041
    Schlagwort(e): Phenylbutazone ; pharmacokinetics ; model ; retrospective analysis ; digestive-tract hemorrhage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Phenylbutazone treatment can cause digestive-tract hemorrhages, but its concentration in the blood at the time of hemorrhage is generally not known. In two patients who had had digestive tract hemorrhages, the variation in the serum phenylbutazone concentration throughout treatment and just before hemorrhage was simulated by a two-compartment model based on assays (gas-liquid chromatography) made after the hemorrhage. Identification of the parameters of the model and simulation of changes in concentration during therapy suggested that the phenylbutazone level in serum at the time of hemorrhage was 101 and 125 µg/ml respectively.
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 29-37 
    ISSN: 1432-1041
    Schlagwort(e): Hydroflumethiazide ; pharmacokinetics ; cardiac failure ; renal drug excretion ; metabolism ; 2,4-disulfamyl-5-trifluoro-methylaniline
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of hydroflumethiazide (HFT) were investigated after single oral doses of 6 µmoles/ per kg body weight in five healthy subjects and in nine patients with moderate cardiac failure. HFT was excreted in urine together with 2,4-disulfamyl-5-trifluoromethylaniline (DTA), which was also present in the blood after administration of HFT. HFT and DTA were determined by TLC and spectrofluorodensitometry. Mean cumulative urinary excretion of HFT was 46.5 and 47.5 per cent of the dose both in healthy subjects and in patients. Distribution half-life (t1/2α) was about 2 h in both groups of subjects, while biological half-life (t1/2β) ranged from 12.4 to 26.9 h (mean 16.6) in healthy subjects, and from 6.3 to 13.7 h (mean 9.6) in patients. Mean renal clearance was 0.33 and 0.211 · h−1 · kg−1 in normal subjects and patients, respectively, and was almost equal to the total body clearance. HFT had a large apparent volume of distribution (Vβ), with mean values of 6.4 and 3.11 · kg−1 in normal subjects and patients. Mean cumulative urinary excretion of DTA was 1.8 and 1.9 per cent in healthy subjects and patients with cardiac failure. The apparent half-life of DTA, determined from urinary excretion rate in eleven subjects, ranged from 16 to 56 h but half-lives in three others were more than 100 h. The results indicate that HFT is partly metabolized in the body to DTA, and DTA and HFT are excreted in urine. The half-life of DTA was longer than that of the parent drug. The apparent volume of distribution, clearance and biological half-life of HFT were lower in patients with cardiac failure than in healthy subjects.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 361-366 
    ISSN: 1432-1041
    Schlagwort(e): Furosemide ; gestosis of pregnancy ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Furosemide 50 mg was administered orally and intravenously to twelve gestotic women for brief periods as a part of a randomized, multicentre clinical trial comparing the efficacy of bed rest and pharmacological treatment. The pharmacokinetic profile was investigated using a gas-liquid chromatographic technique. The plasma half-life after oral and intravenous administration was 115±37.1 and 71.8±26.3 min and plasma clearance was 153±48 and 152±23 ml/min, respectively (mean±SD). Comparative data from healthy pregnant women cannot be obtained for ethical reasons. The results show that gestosis has only a marginal if any effect on the kinetics of furosemide in comparison with published kinetic parameters in healthy volunteers and patients with renal failure. The new-born babies where checked for side effects according to a protocol in use in a larger regional surveillance programme. No clinical side-effects were attributable to furosemide, but the small size of the group does not permit any definitive conclusions about this aspect.
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 281-291 
    ISSN: 1432-1041
    Schlagwort(e): Phase I clinical trial ; complex protocol ; tolerance ; pharmacokinetics ; praziquantel ; anthelmintic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The tolerance of Praziquantel (2-cyclohexylcarbonyl-1, 3, 4, 6, 7, 11b-hexahydro-2H-pyrazino-[2, 1-a]isoquinoline-4-one) in oral doses of 1×20 mg/kg, 1×50 mg/kg, 3×10 mg/kg and 3×25 mg/kg body weight (τ=4 h) was tested in a complex study involving 36 healthy volunteers. In addition to the usual assessment of clinical chemistry, haematology, coagulation physiology, urinalysis, clinico-physiological examination including EEG, and medical examination, clinico-psychological parameters were also recorded and special neurological investigations were performed. No clinically relevant changes were found in any of the laboratory parameters, nor in the medical-neurological or clinico-physiological examinations. Based on a few clinicopsychological parameters and subjective comments, the largest daily dose tested (3×25 mg/kg=75 mg/kg) produced a slight, transient disturbance in general well-being, which was barely detectable on objective clinical examination. The pharmacokinetic behaviour was dominated by rapid metabolism and pronounced first-pass metabolism of praziquantel, which greatly limits the value of results obtained by GC analysis of unchanged drug in serum. The peak concentration in serum was reached after 1– h, and the elimination half-life for the period 2–8 h was 1–1.5 h.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 35-39 
    ISSN: 1432-1041
    Schlagwort(e): Norethindrone ; bioavailability ; man ; competitive protein binding ; sex differences ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A competitive protein binding assay for norethindrone was developed to measure plasma levels in human subjects. The plasma levels were considerably higher in women than in men, especially at low dose levels. The plasma levels were directly related to the dose in men; but greater variations in the plasma levels were observed in women. The plasma half-life was about 5 h in both sexes with single oral doses of 5 to 20 mg. A comparative bioavailability study with norethindrone from 2 different manufacturers, formulated in the same manner, showed no significant differences in absorption characteristics and provided sufficient data for pharmacokinetic analysis.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 119-124 
    ISSN: 1432-1041
    Schlagwort(e): Bendroflumethiazide ; pharmacokinetics ; hypertension ; renal clearance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary After four weeks on placebo treatment, 8 hypertensive patients (WHO stage I) were treated for 2 weeks with bendroflumethiazide (bft) 2.5 mg and KCl 1.5 g daily. Subsequently they received bft 5 mg and KCl 1.5 g daily for a further fortnight. At the end of each period of treatment blood pressure was recorded and blood samples and urine were collected for analysis of bft by GLC. Before taking the daily dose of bft, no trace of the drug was found in plasma. Peak levels of bft were seen after 2.3 h and averaged 23 and 50 ng · ml−1 after 2.5 and 5 mg, respectively. After bft 2.5 mg the plasma level was too low for kinetic analysis. The plasma half-life after 5 mg averaged 4.1 h. The mean apparent volume of distribution was 1.18 l · kg−1. Non-renal clearance averaged 200 ml · min−1. The renal clearance of bft was significantly lower (p〈0.05) after 5 mg (48 ml · min−1) than after 2.5 mg bft (93 ml · min−1), although the creatinine clearance remained unchanged. No correlation was found between the plasma level of bft and its effect on blood pressure.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 13 (1978), S. 445-448 
    ISSN: 1432-1041
    Schlagwort(e): Cephacetrile ; pharmacokinetics ; renal Impairment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of cephacetrile, administered as a single i. v. injection of 15 mg/kg, have been determined in 8 patients with normal renal function and in 12 patients with a varying degree of renal impairment. A two-compartment model was used to describe the biphasic decline in serum concentrations and to calculate the amount of antibiotic in the central and peripheral compartments. In patients with normal renal function the following values were obtained for various pharmacokinetic parameters: α=3.971 h−1; β=0.343 h−1; K12=1.745 h−1; K21=0.763 h−1; Kel=1.793 h−1; Vc=8.181; Vp=18.401 and Vdss=26.581. Cephacetrile had some of the highest apparent distribution volumes of all the cephalosporins. Impaired renal function significantly affected α, β, K12, and Kel. A linear relationship between Kel of cephacetrile and creatinine clearance was demonstrated. The elimination of cephacetrile in anuric patients was about ten times slower than in patients with normal renal function.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 293-299 
    ISSN: 1432-1041
    Schlagwort(e): Breath analysis ; 14CO2 exhalation ; drug metabolism ; glycodiazine ; liquid chromatography ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Exhalation of14CO2 in breath has been used to assess the rate of hepatic demethylation of (14C-dimethyl)aminopyrine, but due to the complexity of aminopyrine metabolism the pharmacokinetics of the procedure are insufficiently understood. Therefore, studies were performed in five individuals after oral administration of (14C-methoxy)glycodiazine, a model substance with relatively simple kinetic properties. Plasma concentrations of the drug and urinary output of its metabolites measured by high pressure liquid chromatography were analysed by a two-compartment open model. The terminal disappearance of14CO2 from breath was practically identical with the terminal disappearance of glycodiazine from plasma, which could be correlated with the plasma clearance of free glycodiazine. The mean transit time of14C-atoms from plasma to breath was 3 h. These results contribute to the pharmacokinetic basis for use of14C-demethylation breath tests. In particular, they are consistent with the hypothesis that14CO2-breath analysis may be used to assess certain pharmacokinetic parameters of appropriately labelled test compounds. These parameters may not necessarily be a direct reflection of the rate of demethylation.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 14 (1978), S. 405-412 
    ISSN: 1432-1041
    Schlagwort(e): Colloidal plasma substitutes ; cross-linked polypeptides ; Haemaccel® ; pharmacokinetics ; renal failure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Infusions of 3.5% isocyanate cross-linked polypeptide solution 500 ml were given to 52 patients with normal or impaired renal function: glomerular filtration rate (GFR)=0–133 ml/min. The serum concentration and urinary excretion of hydroxyproline were measured and the equivalent polypeptide concentrations were calculated from the results. In patients with normal renal function (GFR〉90 ml/min) the proportion of polypeptide excreted in the urine up to 12 h was 45.4±2.6% ( $$\bar X$$ ±SEM), up to 24 h 47.7±2.9% and up to 48 h 49.3±3.4%. In patients with moderate renal insufficiency (GFR=30–90 ml/min) there was no decrease in polypeptide excretion and even in patients with more serious impairment of GFR (11–30 ml/min) 48-h urinary polypeptide excretion was still 40.6±5.9%. In patients with GFR of 2–10 ml/min polypeptide excretion fell to 10.7±3.2% during the first 12 h, although there was an increase in later collection periods as compared to patients with normal renal function −19.9±3.9% in 24 h and 27.0±3.5% in 48 h. The elimination half-life (t1/2) calculated from serum concentrations was 505±30 min ( $$\bar X$$ ±SEM) in patients with normal renal function (GFR〉90 ml/min). Only when the GFR fell below 30 ml/min did it slowly begin to increase. In patients with minimal residual renal function (GFR=0–0.5 ml/min), who were on haemodialysis, the elimination half-life was 985±49 min, i.e. approximately twice the normal. Twice weekly infusion of 3.5% polypeptide solution 500 ml over a period of 6 weeks did not produce any significant cumulation in haemodialysis patients (GFR=0–0.5 ml/min). A weekly dose of polypeptide 35 g appeared to be quite safe when given for several weeks, even to anuric patients. As no significant amount of polypeptide was lost during haemodialysis, the dose can be chosen without taking into account any effect of intermittent haemodialysis.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 505-519 
    ISSN: 1573-8744
    Schlagwort(e): morphine ; first-pass elimination ; pharmacokinetics ; enterohepatic recirculation ; availability ; routes of administration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Morphine was administered to rats by oral, intraportal, and intravenous routes in a dose of 7.6 mg · kg −1.From the serum concentration data after intraportal administration it was calculated that the first-pass elimination of morphine in the liver amounts to 72±2% (sd). The first-pass fraction eliminated after oral administration was 85±7% (sd), thus yielding a contribution by the gut mucosa of 46% to the overall first-pass elimination after an oral dose. The results were obtained with a general compartmental model which included the kinetics of enterohepatic recirculation. The oral availability was also estimated with the aid of pharmacological effect data. This availability was in good agreement with the corresponding value determined from the serum concentration data. The results suggest that morphine is subjected to enterohepatic recirculation and that the slowest phase of decline of morphine concentrations in serum might be due to this physiological process.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 265-282 
    ISSN: 1573-8744
    Schlagwort(e): pharmacokinetics ; linear systems analysis ; in vivo dissolution rates ; absorption rates ; metabolic rates ; bioavailability ; numerical desconvolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The application of certain aspects of linear systems analysis to pharmacokinetic-problems is described. Topics covered include the evaluation of in vivodissolution rates, absorption rates, and metabolic rates, and the use of pharmacological data. Relevant numerical procedures are also discussed.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 315-325 
    ISSN: 1573-8744
    Schlagwort(e): percutaneous penetration ; methotrexate ; compartmental models ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Compartmental models were developed to describe the penetration of a drug from a topically applied vehicle through the skin. Data for in vitro penetration of methotrexate through hairless mouse skin from vehicles varying in PH from 3.5 to 6.5 were computer- fitted to estimate model parameters. Comparison of lag time and the exponential coefficient suggested that parallel penetration pathways exist. The fraction of drug penetrating through the shunt pathway increased as vehicle pH and ionization increased. Penetration curves were quantitatively partitioned into bulk tissue and shunt contributions. At pH 6.5, flux through the shunt pathway predominated.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 521-537 
    ISSN: 1573-8744
    Schlagwort(e): compartmental analysis ; doxantrazole ; drug distribution ; mathematical prediction ; pharmacokinetics ; rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A pharmacokinetic model incorporating 14 compartments and 29 transfer coefficients has been developed from experimental data obtained after intravenous administration of a single dose to describe the distribution of doxantrazole in the rat. The distribution calculated from the model agreed closely with that determined experimentally. In addition, the model was able to predict with considerable accuracy the distribution of doxantrazole after repeated dosing.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 187-196 
    ISSN: 1573-8744
    Schlagwort(e): Chlorpromazine ; pharmacokinetics ; oral absorption ; single dose
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A single oral dose (120 mg/m2) of Chlorpromazine hydrochloride was administered to four healthy subjects and the blood levels of Chlorpromazine were determined with time. Appropriate equations describing the two-compartment open model with zero-order absorption and the two-compartment model with first-order absorption, both with a lag time, were fitted to the observed data using weighted nonlinear least-squares regression analysis. Fitting the two-compartment model with zero-order absorption and a lag time to the observed data resulted in a significant reduction of the weighted sum of squared deviations, i.e., better correlation between the observed and calculated data, and a closer random scatter of the observed concentration data around the calculated curve with no apparent systematic deviations from the curve. These results suggest that Chlorpromazine absorption is zero order. Chlorpromazine began to appear in the systemic circulation after a mean lag time of 0.4 hr and continued to be absorbed for approximately 2.9 hr. The mean half-lives of the distribution and elimination phases were 1.63 and 17.7 hr, respectively.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 547-558 
    ISSN: 1573-8744
    Schlagwort(e): statistical moments ; network theory ; pharmacokinetics ; bioavailability ; deconvolution ; plasma concentration-time curve ; urinary excretion rate-time curve ; compartment models
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Statistical moments are parameters that describe the characteristics of the time courses of plasma concentration (area, mean residence time, and variance of residence time) and of the urinary excretion rate that follow administration of a single dose of a drug. The relationship between the moments of a time-course curve and pharmacokinetic profiles of drug disposition, i.e., absorption, distribution, metabolism, and excretion, is described. The moments are related to the extent and rate of bioavailability, and it is shown that they can be effectively applied to the deconvolution operation.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 539-546 
    ISSN: 1573-8744
    Schlagwort(e): trapezoidal rule ; area under the curve ; pharmacokinetics ; clearance ; bioavailability ; integration method ; sulfisoxazole
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The linear trapezoidal rule method is commonly used for the estimation of the area under the plasma level-time curve. Error analyses are performed when the method is used in first-order absorption and first-order elimination kinetics in the one-compartment system. It is found that significant underestimations and overestimations in area during the absorption phase and postabsorption phase, respectively, can occur when the method is improperly used. During the exponential postabsorption phase the relative error is only a function of the ratio (n)of the time interval over the half-life of the two plasma data points in the interval. The error from the linear trapezoidal rule method at n=0.5 is about 1%. The error increases to 15.5% and 57.1 % when nis increased to 2 and 4, respectively. It is recommended that for most absorption studies the linear trapezoidal method be used for prepeak and plateau plasma data and the logarithmic trapezoidal method for postpeak plasma data.
    Materialart: Digitale Medien
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 295-303 
    ISSN: 1573-8744
    Schlagwort(e): tetracycline ; antibiotics ; Billroth-II gastrectomy ; gastrectomy ; pharmacokinetics ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The bioavailability of a single 250-mg oral dose of tetracycline hydroghloride was studied in seven patients following Billroth-II gastrectomy in comparison with seven control subjects matched for age and body weight. There were no significant differences between control subjects and gastrectomized patients in the apparent lag time prior to the start of absorption (23.6 vs. 22.8 min), peak serum tetracycline concentration (1.72 vs. 1.75 μg/ml), the time of attainment of peak concentrations (3.35 vs. 3.42 hr), the apparent first-order absorption half-life (1.8 vs. 1.4hr), or the apparent first-order elimination half-life (8.0 vs. 8.7hr). Completeness of tetracycline absorption, as judged by area under the 24-hr serum concentration curve, did not differ significantly between the two groups, nor did 24-hr urinary excretion of tetracycline. Thus the abnormalities of gastrointestinal structure and function produced by Billroth -II gastrectomy do not result in impairment of the rate and completeness of tetracycline absorption.
    Materialart: Digitale Medien
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Journal of pharmacokinetics and pharmacodynamics 6 (1978), S. 369-387 
    ISSN: 1573-8744
    Schlagwort(e): pharmacokinetics ; dog ; diethyldithiocarbamate metabolite of disulfiram ; presence of methyl ester ; kinetic evaluation of prior studies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Following the intravenous infusion of sodium diethyldithiocarbamate to dogs, the disposition kinetics of diethyldithiocarbamate (DDC), a metabolite of disulfiram, were assessed. Approximately 27% of the administered dose was S-methylated, this process exhibiting a mean first-order rate constant of 0. 0569 min−1 (t1/2=12.2 min), while the remainder was eliminated by other routes having a rate constant of 0.148 min−1 (t1/2=4.68 min). The methyl diethyldithiocarbamate (MeDDC) formed from DDC showed an elimination rate constant of 0.0141 min−1 (t1/2=49.2 min). These observations are discussed in the light of previous investigations where the presence of MeDDC has rarely been sought or reported. A few comparisons with prior studies, in which DDC or disulfiram was administered, are made by retrospective kinetic evaluation of published data. The results are discussed in relation to the duration of action of disulfiram in man.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 35-43 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Expressions were derived for combined pressure and diffusional transition region flow of gases in porous media. Experimental systems were developed to verify the applicability of the equations for packed columns of Kaolinite clay and quartz sand with methane and carbon dioxide flowing into nitrogen.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 101-106 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: This paper presents a simplified formulation for ∊H for low to moderate Prandtl number fluids and for ∊M that utilizes the surface renewal model, but which also accounts for the fact that eddies do not reach the surface. The predicted trend in Prt obtained on the basis of the present analysis suggests an opposite dependency on Pr to that predicted by many of the other analyses.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 44
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 154-156 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978) 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 30-34 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Conversion was measured in small packed-bed reactors containing immobilized glucoamylase in a range of variables in which diffusion was an important limitation. Three sets of data involving two carriers and two temperatures agreed satisfactorily with the theory of simultaneous reaction and diffusion.Several reactors were designed for 99% conversion, and the results show that diffusion is a small problem when feed concentration is high but a serious problem at low concentration, requiring careful design of the catalyst. The particle size needed to eliminate the effect of diffusion is shown as a function of length.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 72-87 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The gasification of a single particle of porous char surrounded by a boundary layer with oxygen and water vapor in its environment, taking into consideration the six main reactions along with the appropriate heat and mass transport effects, is considered using a shell-progressive model. Much can be done analytically, and the numerical treatment of the model equations for a variety of parameters elucidates the structure of the problem which is much more complicated than anticipated, in spite of the fact that the model is a relatively simple one. The flame front of burning hydrogen and carbon monoxide can be at the core surface, in the ash layer, or in the boundary layer depending upon the ambient conditions of temperature and oxygen concentration.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 106-115 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Most coals swell when heated, and their plastic properties change. These phenomena are explained qualitatively and semiquantitatively using a theory which combines classical nucleation theory and chemical kinetics.Classical bubble nucleation theory is modified to include cases where gases are formed in a liquid as a result of a chemical reaction. Part of the gas that is formed in the liquid escapes through the surface. However, the concentration of gas that remains in the solution increases until a critical concentration is reached. When the critical concentration of gas in the solution is reached, bubbles will begin to nucleate.The value of the rate of nucleation has a critical upper limit which is determined by the thermodynamic properties of the solution. However, the kinetics of the heat, momentum, or mass transfer may reduce the thermodynamic rate.The criteria to decide which transport mode limits the kinetics of the nucleation were derived and applied to melting coal. In coal, the rate of bubble nucleation appears to be limited by the rate of momentum transfer in the melt.The size of the melting coal particle determines the ratio of surface area to volume and thus affects the kinetics of the accumulation of gaseous reaction product in the melt. Thus, smaller rates of bubble nucleation will be observed in smaller coal particles (very viscous melts).Kinetic equations are derived and used to estimate the time that is required for bubbles to appear inside a coal particle. A general method is proposed to calculate the time-temperature contour at which nucleation will occur. The effect of the particle size on the time of nucleation is calculated. The results of the calculations yield values which compare very well with experimental results on coal.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 170-180 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Experiments were carried out with water dispersed in hydrocarbons at various flow rates. The measured size spectra can be well represented by either an upper limit log-probability function or a Rosin-Rammler type of equation with constant parameters and only one variable, the maximum drop diameter dmax or d95. The latter can be predicted satisfactorily by a correlation based on the Hinze/Kolmogorov model of droplet breakup.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 303-315 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Minimum cost surfaces compare eight distillation systems separating ternary feeds. The region of optimality for a design varies with the species separated, but some tower configurations are always preferred at particular feed compositions.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
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  • 51
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 294-302 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Three-phase reactors involving a solid catalyst are normally used for production of product or removal of impurity. Equations are presented for these two measures of reactor performance for a first-order, reversible or irreversible reaction in an isothermal reactor. The results are presented in terms of dimensionless groups of the pertinent mass transfer, kinetic, and equilibrium (solubility) properties, and the gas and liquid flow rates. From the equations given, it is possible to predict the relative performance of concurrent (trickle bed) and countercurrent flow reactors and also the effect of mixing in the gas or liquid streams on performance.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 52
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 598-606 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Mass and population balances, together with nucleation kinetics of the potassium chloride system, were combined to present a design oriented model which describes the behavior of a fines destruction system (FDS) implemented in an MSMPR crystallizer. This model was tested in a well-documented, bench scale, potassium chloride crystallizer and was found to be adequate to predict the effect of fines dissolving. Product size improvement was related to incremental cost incurred with an FDS.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 626-632 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The vaporization and combustion of a miscible multicomponent droplet in a quiescent atmosphere is analyzed by assuming transient-diffusive transport within the droplet, quasi steady diffusive-convective transport in the gas phase, and ideal solution behavior for the mixture. Results on the vaporization of a binary droplet show that owing to the significant liquid phase diffusional resistance, the vaporization process approximately consists of an initial transient regime, an intermediate, diffusion limited, almost quasi steady regime, and a final volatility limited regime. It is further demonstrated that the entrapment of the volatile components within the rapidly heated droplet interior may lead to the initiation of either homogeneous or heterogeneous nucleation, which can result in the fragmentation of the parent droplet with the internal pressure buildup.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 54
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 348-351 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 360-364 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 368-368 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 406-417 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Given the partial oxidation products of methane as the chemical feedstock for single-cell protein (SCP) production, their conversion efficiency is optimized by optimal selection of the pertinent microorganisms that can utilize the feedstocks. The coenzymes of the three oxidation steps from methanol to formaldehyde to formate and carbon dioxide as well as the pathway involved in carbon fixation determine the cell-mass yield. Microorganisms which follows the ribulose monophosphate cycle and which have coenzymes which are linked to the maximum production of ATP (for example, NAD linked dehydrogenases), should be searched for economical production of SCP. Batch growth rate and yield data are limited in utilization and interpretation, and care should be exercised in their use. The subject of this case study, Methylomonas EP-1, gives an optimal cell mass yield of 65% and a stable chemostat operation at space velocities as high as 0.58 hr-1.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 58
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978) 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 750-752 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 61
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 537-540 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 62
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 552-554 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 559-560 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 577-587 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A framework is developed which provides predictions of multicomponent ion exchange equilibria from binary data.Experimental data are reported for the ion exchange equilibria of the binary systems SO42--Cl-, SO42--NO3-, and Cl--NO3- on a strong base anion exchange resin. These systems exhibit nonideal characteristics in both phases, and the experimental characterization has been based on the reaction equilibrium constants and correlations for the activity coefficients in both phases. The exchanger phase activity coefficients are obtained from the well known Wilson (1964) modelThe predictions of the ternary system SO42--NO3--Cl- based solely on the binary data are consistent with the experimental data for this system.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 65
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 619-626 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The importance of the starting point, the size of initial search region, and the search region reduction rate is examined with respect to the reliability of different direct search optimization procedures in being able to furnish the global optimum for nonunimodal systems. Although, in general, the reliability of an optimization procedure is problem dependent, it is nevertheless clear that reliability cannot be increased simply by selecting larger search regions or by reducing the rate of contraction of the search region. A more efficient means of increasing reliability is to embody a pseudo one-dimensional search in the optimization procedure to enable the search to leave a local optimum and proceed to a better optimum.
    Zusätzliches Material: 16 Tab.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 654-664 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A simple and practical method is presented for the control of first-order flow processes with time varying gain and a pure delay in the measurement of the control variable. It involves on-line identification of the process gain and a subsequent adjustment of the controller parameter. The method is well suited for applications in the chemical process industries where high frequency fluctuations in the process gain are not generally expected. It is tested on a computer simulated process as well as experimentally by application to a continuous stirred-tank neutralization process involving pH control, where buffer concentration in the feed varies with time. There is a potential for the application of this method to an industrial process such as wastewater treatment.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 966-976 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A molecular-thermodynamic correlation is established for calculating vapor-liquid equilibria in aqueous solutions containing one or more volatile electrolytes: ammonia, carbon dioxide, hydrogen sulfide, sulfur dioxide, and hydrogen cyanide. The correlation is similar to that presented in 1975, but the domain of application has been increased. The present correlation holds from about 0° to 170°C and for ionic strengths of about 6 molal; for the weak electrolytes considered here, this corresponds to total concentrations between 10 and 20 molal. To represent activities at these high concentrations, activity coefficients are expressed as a function of molality by Pitzer's equation. Required parameters are estimated from data reduction or from correlations.Special attention is given to the ternary systems ammonia-carbon dioxide-water and ammonia-hydrogen sulfide-water. Calculated equilibria are in satisfactory agreement with the severely limited experimental data now available.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 68
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 1046-1054 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The influence of combined forced and free convection on the performance of a reverse osmosis system in a horizontal circular pipe is examined. The free convective motion, which is superimposed upon the main axial flow, is caused by buoyancy forces arising from the buildup of a dense solute boundary layer near the membrane surface. The three-dimensional convective diffusion problem is solved by dividing it into a perturbation part accounting for the buoyancy effects present for Ra ≠ 0 and a nonperturbation part for the intrinsic convective flow pattern present even when Ra = 0.An approximate solution to the nonperturbation equations is obtained from the literature, and the perturbation equations are solved using a stream function-vorticity scheme valid for high Schmidt numbers. The effects of rejection parameter, Rayleigh number, and pressure parameter on the Sherwood number and concentration polarization are studied. Correlations are developed for the asymptotic Sherwood number and the effective axial length at which free convection becomes significant. The numerical results are in reasonable agreement with limiting analytical solutions and with the experimental asymptotic Sherwood numbers measured by Derzansky and Gill (1974) and Hsieh et al. (1976).
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 69
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 1080-1087 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A method for the interpretation of data which results from a signal altered by a process of known weighting function was developed. The method is based on the numerical evaluation and inversion of the Laplace transform. For two different weighting functions, it is shown how narrow a signal can be interpreted accurately. The method is then applied to coal volatilization data.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 1108-1112 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Analytical solutions are presented for laminar plane Couette flow of a power law non-Newtonian fluid. Effects of an additional negative pressure gradient were included in solving for the velocity distribution. The contributions due to the entrance heating region and the viscous dissipation effects were included in arriving at the temperature distribution and also the variation of the local Nusselt number at the stationary plate.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 1125-1127 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 1138-1141 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 73
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 1021-1028 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A new strategy is proposed for the optimum design of chemical plants whose uncertain parameters are expressed as bounded variables. The design is such that the plant specifications will be met for any feasible values of the parameters while optimizing a weighted cost function which reflects the costs over the expected range of operation. The strategy is formulated as a nonlinear programme, and an efficient method of solution is derived for constraints which are monotonic with the parameters, a case which arises frequently in practice. The designs of a pipeline with a pump, of a reactor-separator system, and of a heat exchanger network, all with uncertain technical parameters, illustrate the effectiveness of the strategy for rational overdesign of a chemical plant.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 1055-1063 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A systematic study is presented of the objective functions applicable to the reduction of vapor-liquid equilibrium data by regression procedures based on the principle of maximum likelihood. Numerical results are based on a set of artificial x-y-P data constructed so as to conform to the assumptions that underlie proper application of this principle.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 75
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 1076-1080 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A comparison of experimental and theoretical surface tensions leads to a correlation between homogeneous fluid parameters and the inhomogeneous influence parameter c. From this correlation, it is possible to predict, to within excellent agreement with experiment, the surface tensions of normal alkanes and alcohols from bulk data only.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 466-473 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Mixing rates of particles and gases in confined, coaxial jets are reported for tests with conditions simulating those of pulverized coal gasification and combustion processes. Gas velocity, particle mass flux, and gas composition were measured at various radial and axial locations downstream of the primary jet exit plane. Effects of inlet velocity, density, injection angle, particle loading level, and particle size on the rates of mixing were determined. Increasing injection angle and secondary velocity significantly increased gas and particle mixing rates, while effects of other variables were much less significant. Dispersion of particles lagged that of the gas in all cases investigated.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 500-509 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Methods are presented for the construction of optimal and suboptimal estimators for inferential control systems. Optimal estimators are constructed with the aid of Kalman filtering techniques applied to linear systems driven by integrated white noise disturbances. The description of the disturbances as integrated white noise leads to optimal dynamic estimators which reduce to optimal static estimators for sustained disturbances. Suboptimal estimators are constructed by prespecifying the structure of the estimator and choosing estimator parameters so as to minimize the mean square error in estimation.Optimal and suboptimal estimators are compared by using them in an inferential control system which attempts to control the product composition of a simulated multicomponent distillation column. There is little difference in performance between optimal and suboptimal estimators which use temperature and flow measurements to estimate product composition. However, the inferential control system using a simple suboptimal estimator is significantly superior to the policy of maintaining a selected tray temperature constant through a standard feedback control system. The inferential control system is also superior to composition feedback control systems where the measurement delay is greater than 5 min.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 524-530 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Experimental values of the surface velocities vs of water jets have been obtained by high speed flash cine photography of talc particles on the surfaces of both laminar and turbulent jets. Values of the surface ages as defined variously by Defay and Hommelen (1958), Hansen (1964), and Harper (1973) have been obtained from our data for both pure water and for dilute solutions of surface active agents.We find, by comparison with published entry length corrections for gas absorption, that x/vs gives the most reasonable age of the surface at any distance x along a jet of pure water.If a surface active agent is present in the water, the amount of adsorption of a few millimeters downstream from the nozzle is of the order ten times greater than calculated for laminar jets and five to six times greater than calculated for turbulent jets at Ren = 18 800. This we ascribe to liquid circulation in the jet adjacent to the nozzle, caused by the Marangoni surface flow, which also reduces vs significantly.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 79
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 548-552 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 80
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 344-347 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 357-360 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 367-367 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 369-400 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: This review evaluates the present state of the art on backmixing in gas-liquid and gas-liquid-solid reactors. A brief outline of numerous techniques for measuring residence time distribution (RTD) of various phases in a multiphase reactor is presented. This is followed by a brief description of differential and stagewise models for characterizing backmixing from RTD measurements. Both simple (that is, single-parameter axial dispersion model) and more complex (that is, two-, three-, or four-parameter models) models are evaluated. Backmixing characteristics of various gas-liquid columns such as trickle beds, spray columns, mechanically agitated columns, plate columns, fluidized bed columns, etc., are subsequently evaluated. The performance of a bubble column under various reaction conditions is analyzed. Criteria for the elimination of backmixing in packed-bed reactors are presented, and the effect of backmixing on the multiple steady states in a gas-liquid reactor is briefly reviewed. Finally, the scale-up problems associated with gas-liquid reactors with various degrees of backmixing and the recommendations for the future work in RTD and macromixing models are outlined.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 84
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 427-439 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: An experimental study has been done on the flow of viscoelastic liquids squeezed between two flat parallel plates. In fast squeezes under a constant load, the plates did not come together as rapidly as predicted by inelastic fluid theory. Our experimental data suggest that this device is not generally useful as a viscometer.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 733-735 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 86
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 439-450 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Radial liquid distribution was measured for concurrent downflow of air and water through beds packed with catalyst particles. The experimental results can be predicted by a theory involving two parameters, a spreading factor S and wall factor f. Criteria are presented for predicting operating conditions (particle size and shape and tube diameter) for which the equilibrium distribution will be uniform and packed-bed depth required to attain equilibrium liquid distribution.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 473-485 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The use of tracer dispersion measurements in conjunction with associated pressure drop data, as an indirect diagnostic technique for the determination of particle deposit morphology in deep-bed filters, was investigated. The dispersion measurements consisted of the injection of an electrolyte tracer pulse at the inlet and the monitoring of the tracer peak as it traveled down the bed, while the pressure drop data consisted of the axial pressure gradient histories as deposition took place. These data are interpreted using dispersion and pressure drop theories established on the basis of assumed models of deposit morphology. The validity of this technique was confirmed experimentally.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 509-519 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The turbulent diffusion mechanism of particles in a round air jet are studied both theoretically and experimentally, with particular attention to the relative velocity between particles and fluid, overshooting effect of particles, and the distributions of fluid properties in space. The results indicate that the particle diffusivity decreases with the increase of the particle inertia. In general, the turbulent diffusivity of particles in an air jet is smaller than that of fluid scalar quantities. The particle inertia and the fluid large eddies, which are expressed by the Stokes number and the integral scale, respectively, play an important role in the transport mechanism of particles.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 830-839 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: As an alternative to tearing, symbolic permutation may be used to facilitate data processing rather than dimensional reduction in equation solving, permitting a reduction in computing effort without introducing any deleterious effects on the numerical convergence. Data structures and processing techniques suitable for this purpose have been successfully devised and tested. A program incorporating these techniques has been implemented on a CDC 6400 computer and used to solve irreducible systems of up to 551 linear and nonlinear equations.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 90
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 880-885 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A fourth parameter to be used in conjunction with Pitzer's acentric factor is proposed to correlate the thermophysical properties of anormal fluids. It is based on the saturated liquid density at a reduced temperature of 0.7. A correlation for saturated liquid densities of anormal fluids is presented to cover a reduced temperature range from 0.42 to 1.0. For four hundred and fifty-six data points, covering twenty-one compounds, calculated average and average absolute deviation in predicted saturated liquid densities are -0.05 and 1.11%, respectively.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 912-920 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: This paper deals with a particular type of limit cycle in chemical reaction systems, the so-called relaxation oscillation. This phenomenon can be caused by thermal or kinetically induced instabilities in a loop reactor or a CSTR, but can also occur in a catalytic fixed-bed reactor for an endothermic reaction with self-inhibiting or self-accelerating steps.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 940-941 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978) 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 686-693 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Feedback control of an open loop, unstable, continuous flow, stirred-tank biological reactor was investigated theoretically using several microbial growth models. The closed loop system can be made globally stable, but constraints on the manipulated variable can lead to as many as five steady states, which are either saddle points or locally stable nodes.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 705-709 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Complete interfacial profiles are generated for the gravity flow of a thin film into a stagnant pool. The profiles show standing waves and a rapid thinning of the film just above the static meniscus over the pool. Such effects are encountered, for example, at the bottom of wetted wall columns.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 96
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 728-731 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 738-741 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 748-748 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 803-810 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: An analysis is made on the influence of heat transfer and interfacial shear on the hydrodynamic stability of thin liquid films flowing down an inclined plane. The linear stability of the flow is determined by a successive perturbation solution of the governing Orr-Sommerfeld equation modified to include the effects of temperature on viscosity. Stability criteria are presented which show that a cooled wall is destabilizing, while a heated wall is stabilizing. The surface perturbation stresses of the concurrent gas shear are also shown to be destabilizing factors. Neutral stability curves are presented and compared with the isothermal case.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 839-848 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: SPARSCODE was evaluated based on the simulation of natural gas liquefaction using multicomponent refrigerants. Results obtained on four cases containing 179 to 573 equations show a computing time reduction by a factor of 40 to 250 in equation solving and an overall reduction by a factor of 4 to 30 for the simulation.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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