Incorporation of zolpidem and methoxyphenamine into white hair strands after single administrations: Influence of hair pigmentation on drug incorporation

Variability associated with interpreting drugs within forensic hair analysis: A three‐stage interpretation

“…The study had also identified that the zolpidem, which had been incorporated into the hair bulb was less likely than methoxyphenamine to be further incorporated into the hair shaft during the hair growth phase, suggesting that this is likely attributed to the higher lipophilicity of zolpidem. This is also in agreement with other observed and expected drug lipophilicity behaviour (Kintz, ; Nakahara et al, ; Shima et al, ).…”

“…Matrix‐assisted laser desorption ionization‐time of flight‐imaging mass spectrometry (MALDI‐TOF‐IMS) of 30 mm longitudinally cut hair segments by Kamata et al () revealed that methoxyphenamine administered to volunteers (50 mg) had entered the hair by two routes, i.e., (a) hair bulb, and (b) keratinized upper dermis. Furthermore, Shima et al () observed that after a single dose of 50 mg methoxyphenamine and 10 mg zolpidem the incorporation of drugs through these two routes was dependent on both the lipophilicity of the drug, and the presence of hair pigmentation. Observations in this study showed that pigmented hair had incorporated both of these drugs through both the hair bulb and the keratinized upper dermis, while nonpigmented white hair had incorporated predominantly through the hair bulb.…”

Development of an improved method to estimate the days of continuous drug ingestion, based on the micro‐segmental hair analysis

“…A peak on a distribution curve tends to broaden at the root side because a drug in the blood is gradually taken into the hair tissues with hair growth. Additionally, in our previous studies using micro‐segmental analysis 10–13 and the studies by Shima et al using 1‐mm segmentation, 24–26 it has been found that distribution curves of most drugs ingested as a single dose have a major peak derived from the bloodstream and a minor peak derived from sweat/sebum at a 3‐ to 5‐mm tip side of the major peak. As a result, the S R2 and S T2 were the nearest to the hair positions corresponding to the final and first ingestions, respectively (Figure 4A), whereas the position of S M n , the midpoint of S R n and S T n , hardly depends on n used to measure the peak parameters because the positions of S R n and S T n shift to the root and tip sides, respectively, as n increases.…”

Clinical Value of Emerging Bioanalytical Methods for Drug Measurements: A Scoping Review of Their Applicability for Medication Adherence and Therapeutic Drug Monitoring

“…As scalp hair grows on average 1 cm per month, the timeframe to be studied is dependent on hair length, and, indeed, its presence on the subject. Factors that can influence drug incorporation may be the patient's age and hair colour, but also drug factors such as it being ionization constant and lipophilicity [110][111][112]. Further complicating matters are that hair exposure to UV light, chlorine, shampoos and other treatments may lower the hair drug concentration due to drug degradation or extraction [113].…”