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  • 1
    Electronic Resource
    Electronic Resource
    Chlorpromazine in human scalp hair as an index of dosage history: comparison with simultaneously measured haloperidol (1993)
    Springer
    European journal of clinical pharmacology 44 (1993), S. 439-444 
    Details
    ISSN: 1432-1041
    Keywords: Chlorpromazine ; Haloperidol ; scalp hair ; melanin ; dosage history
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The concentration of chlorpromazine (CPZ) in hair was measured to demonstrate its value as an index of individual dosage history and compliance. An animal study using pigmented rats was conducted to confirm the dose-dependent accumulation of CPZ in hair. The concentration of CPZ in hair, newly regrown on a denuded area of the back after the administration of CPZ for 3 weeks, was 4.6, 8.5 and 16.6 ng·mg−1 hair after daily doses of 1.25, 2.5 and 5 mg·kg−1·day−1, respectively, significantly correlated with the daily dose. The concentration of CPZ in black hairs collected from 23 Japanese patients, who had been taking CPZ in fixed daily doses (30–300 mg/day), ranged from 1.6 to 27.5 ng·mg−1, and was significantly correlated both with the daily dose and with the trough plasma concentration at steady state. Several strands of hair collected from each of 5 patients, whose doses of CPZ had been changed within several months before sampling, were cut into 1-cm pieces successively from the scalp end and the concentration of CPZ in each piece was measured. With the assumption of a hair growth rate of 1 cm per month, the individual history of CPZ doses in all patients could be deduced from the distribution of CPZ along the hair shaft. In 5 patients with grizzled hair the concentration of CPZ in white hairs was much lower (〈10%) than in black hairs, suggesting that the strong affinity of CPZ for hair melanin may explain the accumulation of CPZ in black hair. The concentration of co-administered haloperidol (HP) in plasma and hair was also measured in 11 out of 23 patients. The CPZ concentration in hair was much lower than that of HP (about 0.3 to 7.8%), whether the comparison was made on the basis of daily dose or plasma concentration. This finding is discussed in relation to the affinity of the compounds for their melanin and photochemical stability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315540
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Using ofloxacin as a time marker in hair analysis for monitoring the dosage history of haloperidol (1994)
    Springer
    European journal of clinical pharmacology 47 (1994), S. 195-202 
    Details
    ISSN: 1432-1041
    Keywords: Ofloxacin ; Haloperidol ; Scalp hair ; time marker ; dosage history ; HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Hair samples were obtained 1–5 months after ingestion of the antimicrobial ofloxacin, which had been given for 1 or 3 days at the commencement of haloperidol administration, or when its dosage was reduced. The axial distribution of ofloxacin, haloperidol and its active metabolite, reduced haloperidol, was analysed in segments from single strands of hair. Ofloxacin was detected where the content of haloperidol and reduced haloperidol along the hair shaft showed a sharp change, corresponding to the change in dose. When we matched the time scale of the dosage history to the growth rate, which was estimated using ofloxacin as the time marker, the distribution of the haloperidol and reduced haloperidol precisely coincided with the rise and fall in the dose of haloperidol. These findings demonstrate that ofloxacin can serve as a time marker when drug distribution along the hair shaft is used to obtain the drug exposure history of an individual.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194972
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Human scalp hair as evidence of individual dosage history of haloperidol: a possible linkage of haloperidol excretion into hair with hair pigment (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 120-125 
    Details
    ISSN: 1432-069X
    Keywords: Scalp hair ; Haloperidol ; Segmental analysis ; Dosage history ; Melanin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report a method for determining haloperidol concentration in human scalp hair and discuss a possible linkage of haloperidol excretion into hair with the hair pigment melanin. First, an animal study was conducted to support the idea that hair contains amounts of haloperidol corresponding to the doses given and pigmented hair contains much more drug than does unpigmented hair. The haloperidol concentration was measured using a radioimmunoassay technique after hairs were dissolved in 2.5 N NaOH solution and the drug extracted. Pigmented and albino rats, whose hair from an area on the back had been removed beforehand by plucking, were administered either 1,3, or 10 mg of haloperidol (i.p.) per kg body weight every day for 3 weeks. At the end of the administration period hair which had newly grown on the denuded area was plucked and collected. In each of the two groups classified by hair color the drug levels in the hair correlated with the doses given; however, the concentrations in the hair from the albino rats were much lower than those in the hair from the pigmented rats (which was less than 8.5%). Second, black and white hair was collected from each of seven human subjects with grizzled hair, who were receiving or had been administered haloperidol at fixed daily doses for more than 1 month, and the concentration of haloperidol in each type of hair was measured. In the same subject the concentration in the white hair was found to be much lower than that in the black (less than 10%). In three subjects the dosage had been changed before the hair samplings, and segmental analysis of the distribution of haloperidol in the black hair revealed that the dosage history was imprinted along the length, assuming a hair growth rate of 1 cm/ month; the distribution of drug along the white hair less obviously corresponded to the dosage. Third, another keratinized tissue, nail, was collected together with hair samples from 20 patients and the haloperidol level in the nail was measured and compared with that in the hair. The concentration of haloperidol in nail is only about 3.4% of that in hair. Taken together these results suggest that the mechanism for excreting haloperidol into hair is closely linked with that for the hair pigment melanin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00493470
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    Paper (German National Licenses)
    Fulltext
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