Using ofloxacin as a time marker in hair analysis for monitoring the dosage history of haloperidol

Possible biomarkers modulating haloperidol efficacy and/or tolerability

Haloperidol (HP) is widely used in the treatment of several forms of psychosis. Despite of its efficacy, HP use is a cause of concern for the elevated risk of adverse drug reactions. adverse drug reactions risk and HP efficacy greatly vary across subjects, indicating the involvement of several factors in HP mechanism of action. The use of biomarkers that could monitor or even predict HP treatment impact would be of extreme importance. We reviewed the elements that could potentially be used as peripheral biomarkers of HP effectiveness. Although a validated biomarker still does not exist, we underlined the several potential findings (e.g., about cytokines, HP metabolites and genotypic biomarkers) which could pave the way for future research on HP biomarkers.

Examination of a long-term clozapine administration by high resolution segmental hair analysis

The long-term administration of clozapine could be verified by fine segmentation and analysis of single hairs of one person to examine the history of a multiple poisoning case. Segments of 1-2.5mm length were extracted by ultrasonification in 30 microl of the mobile phase (mixture of methanol+water, 50+50). By application of isocratic liquid chromatography and using narrow bore columns (Synergy Polar-RP, Phenomenex), an acceleration and miniaturization of the HPLC-MS-MS assay could be achieved. Total amounts of clozapine down to 30 fg (on column) and its desmethyl metabolite could be analysed in multiple reaction monitoring mode. According to typical sample amounts of approximately 16 microg, relevant hair concentrations higher than 1 pg/mg were detected. Significant and reproducible concentration profiles along the hair fibres revealed characteristic administration cycles. The administration time course - in particular the time of its termination - could be verified with a precision of a few days. The accuracy and reproducibility of the concentration profile was proven based on multiple investigations of single hairs. An individual hair growth rate of 0.55 mm/day was determined with a relative standard deviation of 8% by comparison of concentration profiles in hairs collected after a time span of 165 days.

Comparative dispositions of ofloxacin in human head, axillary, and pubic hairs

The distribution of ofloxacin (OFLX) along the shaft of each of three hair types, i.e., head, axillary and pubic, was investigated and compared among five healthy male volunteers 1 to 4 months after ingestion of OFLX for 1 or 2 days (total dose, 200 or 600 mg). Five strands of each hair type were sectioned together into successive 0.5-cm lengths starting from the dermal end, over a length of < or = 6 cm, and the OFLX concentration in each hair section was measured by high-pressure liquid chromatography with fluorescence detection. The distribution of OFLX along the head hair shaft was narrow, having a single peak even 3 to 4 months after administration, suggesting a rather uniform growth rate among hair strands. On the other hand, the OFLX distribution along axillary or pubic hair shafts tended to be broad, even having two apparent peaks, and the growth rate did not seem uniform. Since axillary hair seemed to stop growing after having gained a length of < or = 4 to 5 cm, it was suggested to enter a resting stage after the growth of < or = 3 cm over the 2 to 4 months after OFLX incorporation. These findings indicate that head hair is the most suitable for analysis of individual drug use and the larger growth rate and cycle stage variabilities of strands of the other types of hair should be taken into account.

Medication compliance as a feature in drug development

Well-designed clinical trials maximize the information that can be obtained regarding the clinical pharmacology of a drug and, in turn, can streamline and enhance the drug development process. Until recently, little emphasis has been placed on integrating the role of variability in individual patterns of drug-taking into the drug development process. With the use of electronic monitoring, the temporal relationship between an individual's pattern of dosing and the prescribed regimen may be examined, and individual drug exposure may be estimated based on the actual history of dosing. As a result, accurate estimation of exposure-response relationships (or surrogate markers of response) can be obtained. Considerations in the design of clinical trials must therefore be expanded to include appropriate methods to measure compliance, sufficient frequency of monitoring to allow the time course of response to be mapped, and the use of statistically valid methods of data analysis.

The axial distribution of nicotine content along hair shaft as an indicator of changes in smoking behaviour: evaluation in a smoking-cessation programme with or without the aid of nicotine chewing gum

1. Hair samples were obtained from subjects at the end of a 6 month smoking-cessation programme carried out with (n = 16) or without (n = 10) the aid of nicotine chewing gum. The axial distribution of nicotine along the hair shaft was determined and compared both with the self-report of smoking behavior and with the concentration of carbon monoxide (CO) in expired air measured at 1 month intervals. 2. A gradual decrease in nicotine content along the hair shaft corresponded to the decrease in self-reported number of cigarettes smoked daily in both the nicotine chewing-gum treated and untreated subjects and with the clinical assessment of abstinence. 3. There was reasonable agreement between the CO content of expired air, the self-reported number of cigarettes smoked daily and the axial distribution of nicotine in 22 of 26 subjects. In the other four subjects there was an apparent disagreement between the CO content of expired air and the other parameters. 4. This study showed that, as a routine marker of smoking status, hair analysis may be preferable to repeated CO measurements since only a single sample at the end of an abstinence programme might be sufficient. However, one problem is that nicotine may dissociate slowly from melanin to limit the ability to mark a sudden cessation of smoking. Also, some nicotine in hair might be attributable to nicotine adsorbed to the outside of hair.