Segmental Hair Analysis after a Single Dose of Zolpidem: Comparison with a Previous Study

Abstract

Hair is a useful aid and sometimes even the only matrix in the analytical strategy in drug-facilitated crime (DFC) investigations. In this novel study, segmental hair analysis was performed after a single 10 mg dose of zolpidem was given to 20 Chinese volunteers. Hair was collected 1 month after administration and was analyzed using ultra-high-pressure liquid chromatography/electrospray ionization tandem mass spectrometry. Zolpidem concentrations were found to be in the range of 135.0-554.6 pg/mg in the proximal 0-2 cm segments. These results were markedly different from those reported by Villain et al., who used volunteers administered equal doses of zolpidem. The analytical method used, as well as the volunteers' hair color, inter-individual variations such as metabolic capacity, hair growth rate, drug incorporation rates, physical state of the hair, age, gender, body weight, etc. and diffusion from sweat or other secretions are all factors that should be considered when interpreting the DFC results.

Systematic investigation of the incorporation mechanisms of zolpidem in fingernails

“…Assuming a hair growth rate of 1 cm per month, segment B should represent a timeframe of three weeks and the anticipated time of intake . Consistent with literature, zolpidem could be detected in hair after single intake . Indeed, highest concentrations were found in the expected hair segment B (c peak values for hair).…”

“…The detection of zolpidem in both vicinal segments can be explained by different growing stages (segment A) and sweat‐ or sebum‐mediated drug transport (segment C), respectively. Our results are in concordance with those obtained by Cui et al ., although concentrations detected were in a 500 times higher range . This may be at most due to the alkaline extraction method used by the authors.…”

“…[2] Consistent with literature, zolpidem could be detected in hair after single intake. [39,40] Indeed, highest concentrations were found in the expected hair segment B (c peak values for hair). Concentrations ranged from 1.1 to 10.8 pg/mg hair (median = 3.8 pg/mg hair) and were comparable with those found by Villain et al [40] However, in our study, zolpidem was also found in the vicinal segments A, representing the time after, and C, representing the time before the intake.…”

New Challenges and Perspectives in Hair Analysis

“…Taking into account only the major issues of these investigations, it is important to note that hair analysis is particularly problematic because (i) the incapacitating drug has allegedly been taken only once, leading to extremely low hair concentration and high analytical sensitivity requirements, (ii) the drug to be detected is potentially comprised within a list of tens of psychoactive substances and is generally not known in advance by the analyst [51À54], and (iii) the circumstantial evidence is frequently disjointed, due to the amnesic effects of the drug. Indeed, under apparently comparable conditions, much lower concentrations were found in real forensic cases [56,63] than in single controlled administrations [42,43]. While general recommendations for segmental analysis suggest the use of 10À30 mm segments [59,60] in order to cope with peak broadening phenomena (diffusion, differential hair growth, etc.)…”

Time‐course measurements of drug concentrations in hair and toenails after single administrations of pharmaceutical products

“…On the other hand, hair and nails are often used to prove chronic intake of drugs over several months. Although the effectiveness of segmental hair analysis for the detection of some drugs has been reported, [5][6][7] the detailed mechanism of drug uptake in hair remains unknown. [1] Therefore, hair and nails can be used as alternative specimens to prove drug intake long after drugs are eliminated from urine and blood.…”