Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Radionuclide therapy  (2)
  • Topotecan  (2)
  • Benzodiazepines  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Pharmacokinetics and pharmacodynamics of topotecan administered daily for 5 days every 3 weeks (1995)
    Springer
    Cancer chemotherapy and pharmacology 35 (1995), S. 237-245 
    Details
    ISSN: 1432-0843
    Keywords: Pharmacodynamics ; Pharmacokinetics ; Topotecan ; Topoisomerase I inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Topotecan is a novel semisynthetic derivative of the anticancer agent camptothecin and inhibits the intranuclear enzyme topoisomerase I. The lactone structure of topotecan, which is in equilibrium with the inactive ringopened hydroxy acid, is essential for this activity. The open form predominates at physiological pH. We performed a pharmacokinetic, study as part of a phase I study in patients with various types of solid tumors, where topotecan was administered in a 30-min infusion daily on 5 consecutive days every 3 weeks. The plasma kinetics of topotecan could be described best using an open two-compartment model with t1/2(α) and t1/2(β) of 8.1 (range 0.3 to 40.7) min and 132 (range 49 to 286) min, respectively. The plasma concentration-time profiles of the metabolite, however, could be described using a one-compartment model with t1/2(formation) of 29.0 (range 5.6–99.5) min and t1/2 (elimination of 123.2 (range 32–265) min, respectively. The lactone was the predominate form during the first hour from the start of infusion, but was rapidly converted into its ring-opened structure. The elimination rate of topotecan was independent of the dose. There were linear relationships between the dose (mg m−2 day−1), the area under the plasma concentration versus time curve (AUC) of topotecan and its metabolite, the total AUC, peak plasma lactone concentrations, and the time period that the topotecan concentrations remained above 10 nM. Different models were used to correlate pharmacokinetic and pharmacodynamic parameters. The percentage decrease in absolute neutrophil count (ANC) was related to these parameters and plots were well fitted by linear and sigmoidal Emax models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686554
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Pharmacokinetics and pharmacodynamics of topotecan given on a daily-times-five schedule in phase II clinical trials using a limited-sampling procedure (1996)
    Springer
    Cancer chemotherapy and pharmacology 38 (1996), S. 254-260 
    Details
    ISSN: 1432-0843
    Keywords: Key words Limited-sampling model ; Pharmacodynamics ; Pharmacokinetics ; Phase II ; Topotecan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Topotecan is a novel semisynthetic derivative of the anticancer agent camptothecin and inhibits the intranuclear enzyme topoisomerase I. The lactone structure of topotecan, which is in equilibrium with the inactive ring-opened hydroxy acid, is essential for this activity. We performed a pharmacokinetics study as part of phase II clinical trials in patients with various types of solid tumors, giving topotecan at 1.5 mg/m2 per day by 30-min infusion for 5 consecutive days, with courses being repeated every 3 weeks. Previously validated limited-sampling models, using concentration measurements in samples obtained 2 h after infusion, were used to calculate the area under the plasma concentration-time curves (AUCs) for both chemical forms. Samples were obtained from a total of 36 patients over 136 treatment days. The mean AUC of the closed-ring form (AUCclosed) was 8.74 (range 2.3–16.3)  μM min per day, and the mean AUC of the ring-opened form (AUCopen) was 11.5 (range 3.2–46.0)  μM min per day (interpatient variability 34–61%). In each patient the AUC values achieved on the 1st day of administration were similar to and, thus, predictive for those achieved during the following days, with a day-to-day variation of 7.39% being recorded for the AUCclosed and that of 12.6%, for the AUCopen. There was no drug accumulation during the 5 consecutive treatment days of each cycle. However, despite the large interpatient pharmacokinetic variability, the importance of regular drug monitoring on this schedule can be questioned, as the pharmacodynamic variability was relatively small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002800050479
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Discriminative stimulus properties of alprazolam (2000)
    Springer
    Psychopharmacology 148 (2000), S. 146-152 
    Details
    ISSN: 1432-2072
    Keywords: Key words Alprazolam ; Drug discrimination ; Benzodiazepines ; Antidepressant ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rationale: The triazolobenzodiazepine alprazolam has a unique clinical profile compared to most other benzodiazepines (e.g. diazepam, chlordiazepoxide), in that it is used to treat panic disorder and is effective in depression, two disorders that are usually treated with anti-depressants. Previous drug discrimination studies suggested that alprazolam has stimulus properties in common with antidepressants. Objective: In the present study, the discriminative stimulus properties of alprazolam were investigated to test more conclusively the role of benzodiazepine receptors and whether alprazolam has stimulus properties in common with antidepressants. Methods: Male Wistar rats (n=12) were trained to discriminate between alprazolam (2.0 mg/kg, PO) and vehicle in an operant two-lever drug discrimination procedure under a tandem VI40”-FR10 schedule of reinforcement. Generalization and antagonism tests were carried out under 2 min extinction. Results: In generalization tests, a number of benzodiazepines (alprazolam, chlordiazepoxide, midazolam, lorazepam) and the barbiturate pentobarbital substituted completely, while zolpidem and abecarnil substituted partially for alprazolam. In contrast, no significant degree of generalization to the antidepressants imipramine and fluvoxamine and the putative antidepressants buspirone and flesinoxan was found. In antagonism studies alprazolam could be antagonized (almost) completely by flumazenil, partially by pentylenetetrazole, but not by methyl 6,7-dimethoxy-4-ethyl-β-carboline-3-carboxylate (DMCM), N-methyl-β-carboline-3-carboxamide (FG-7142) and picrotoxin. Conclusions: These results show that the discriminative stimulus properties of alprazolam are mediated by benzodiazepine receptors and that the finding that antidepressants share discriminative stimulus effects with alprazolam may have limited generality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050036
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Renal excretion of iodine-131 labelled meta-iodobenzylguanidine and metabolites after therapeutic doses in patients suffering from different neural crest-derived tumours (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 544-552 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Metabolism ; [131I]meta-iodobenzylguanidine ; Radionuclide therapy ; Renal excretion ; Urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Iodine-131 labelled meta-iodobenzylguanidine ([131I]MIBG) is used for diagnostic scintigraphy and radionuclide therapy of neural crest-derived tumours. After administration of therapeutic doses of [131I]MIBG (3.1–7.5 GBq) to 17 patients (n=32 courses), aged 2–73 years, 56%±10%, 73%±11%, 80%±10% and 83%±10% of the dose was cumulatively excreted as total radioactivity in urine at t=24 h, 48 h, 72 h and 96 h, respectively. Except for two adult patients, who showed excretion of 14%–18% of [131I]meta-iodohippuric acid ([131I]MIHA), the cumulatively excreted radioactivity consisted of 〉85% [131I]MIBG, with 6% of the dose excreted as free [131I]iodide, 4% as [131I]MIHA and 2.5% as an unknown iodine-131 labelled metabolite. Cumulative renal excretion rates of total radioactivity and of [131I]MIBG appeared to be higher in neuroblastoma and phaeochromocytoma patients than in carcinoid patients. Based on the excretion of small amounts of [131I]meta-iodobenzoic acid in two patients, a possible metabolic pathway for [131I]MIBG is suggested. The degree of metabolism was not related to the extent of liver uptake of radioactivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01267687
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Renal excretion of iodine-131 labelledmeta-iodobenzylguanidine and metabolites after therapeutic doses in patients suffering from different neural crest-derived tumours (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 544-552 
    Details
    ISSN: 1619-7089
    Keywords: Metabolism ; [131I]meta-iodobenzylguanidine ; Radionuclide therapy ; Renal excretion ; Urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Iodine-131 labelledmeta-iodobenzylguanidine ([131I]MIBG) is used for diagnostic scintigraphy and radionuclide therapy of neural crest-derived tumours. After administration of therapeutic doses of [131I]MIBG (3.1–7.5 GBq) to 17 patients (n=32 courses), aged 2–73 years, 56%±10%, 73%±11%, 80%±10% and 83%±10% of the dose was cumulatively excreted as total radioactivity in urine att=24 h, 48 h, 72 h and 96 h, respectively. Except for two adult patients, who showed excretion of 14%–18% of [131I]meta-iodohippuric acid ([131I]MIHA), the cumulatively excreted radioactivity consisted of 〉85% [131I]MIBG, with 6% of the dose excreted as free [131I]iodide, 4% as [131I]MINA and 2.5% as an unknown iodine-131 labelled metabolite. Cumulative renal excretion rates of total radioactivity and of [131I]MIBG appeared to be higher in neuroblastoma and phaeochromocytoma patients than in carcinoid patients. Based on the excretion of small amounts of [131I]meta-iodobenzoic acid in two patients, a possible metabolic pathway for [131I]MIBG is suggested. The degree of metabolism was not related to the extent of liver uptake of radioactivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01267687
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...