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Erschienen in: Forensic Toxicology 2/2023

15.04.2023 | Original Article

Evaluation of applicability of micro-segmental analysis to hair treated with heat and haircare products

verfasst von: Kenji Kuwayama, Hajime Miyaguchi, Tatsuyuki Kanamori, Kenji Tsujikawa, Tadashi Yamamuro, Hiroki Segawa, Yuki Okada, Yuko T. Iwata

Erschienen in: Forensic Toxicology | Ausgabe 2/2023

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Micro-segmental analysis (MSA), which enables the measurement of detailed drug distributions in hair by segmenting a single hair strand at 0.4 mm intervals, is indispensable for estimating the day of drug ingestion. However, haircare with dryers and various products can influence drug concentrations in hair. Therefore, the applicability of MSA to hair that was treated with heat or various haircare products was evaluated.


Reference hair strands containing drugs consistently along the hair shafts were collected from patients who ingested four hay-fever medicines (fexofenadine, epinastine, cetirizine, and loratadine) daily for 4 months. The hair strands were divided into eight 4 mm regions from the proximal end, and each region was placed on an electric hot plate at 100–200 °C or soaked in haircare products, such as shampoo and bleaching agent. The hair regions were subjected to MSA. Moreover, after a patient was administered midazolam at a single dose and the hair was bleached, the day of midazolam administration was estimated using MSA.


Repetitive heating for 1 min and daily haircare products, such as shampoo, hardly affected the drugs in hair, whereas bleaching products containing H2O2 decreased the amounts of hay-fever medicines in the hair up to 58%. However, the amount of midazolam did not decrease in bleached hair and the day of midazolam administration was successfully estimated.


The analytes used in this study were minimally affected by ordinary haircare and could be detected even in bleached hair. Therefore, MSA can be applicable regardless of haircare history.
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Evaluation of applicability of micro-segmental analysis to hair treated with heat and haircare products
verfasst von
Kenji Kuwayama
Hajime Miyaguchi
Tatsuyuki Kanamori
Kenji Tsujikawa
Tadashi Yamamuro
Hiroki Segawa
Yuki Okada
Yuko T. Iwata
Springer Nature Singapore
Erschienen in
Forensic Toxicology / Ausgabe 2/2023
Print ISSN: 1860-8965
Elektronische ISSN: 1860-8973

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