Pharmaceutical Sciences Asia Pharm Sci Asia 2023; 50(1), 24-33 DOI:10.29090/psa.2023.01.22.292 24 Development and validation of a GC-MS method for determination of amphetamine-type stimulants and ketamine in human hair Tran Viet Hung 1 , Ha Minh Hien 1 , Pham Quoc Chinh 2 , Pham Thi Thu Ha 2 , Nguyen Duc Nhu 2 , Nguyen Duc Tuan 3* 1 Institute of Drug Quality Control Ho Chi Minh City, Ho Chi Minh City, Vietnam 2 National Institute of Forensic Medicine, Hanoi City, Vietnam 3 Faculty of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam 1. INTRODUCTION The amphetamine-type stimulants (ATSs) such as amphetamine (AM), methamphetamine (MA), 3,4-methy- lenedioxyamphetamine (MDA), 3,4-methylenedioxyme- thamphetamine (MDMA), 3,4-methylendioxyethylamphe- tamine (MDEA), para-methoxyamphetamine (PMA), 4- bromo-2,5-dimethoxyamphetamine (DOB), and ketamine (KET), norketamine (NKT) are medicines that stimulate the central nervous system causing in hallucination 1,2 . These narcotics were handled in accordance with the regulation on the list of narcotic substances and precursors in Vietnam. In recent years, ecstasy-type (MDMA) and metham- phetamine (MA) have been widely used as a recreational drug among the youth 3 . The abuse of MA and MDMA has significantly increased since 1995s and becomes a serious matter in the society. Teenagers are the main ATSs users and their age was more and more declined 4 . Since 2000s KET has been abused and used more and more together with ATSs 5 . Drug testing provides objective evidence on the illegal use of drug by proper detection of the presence of drug and its metabolites in the body. Thus, it is necessary that a method for simultaneous, rapid, and reliable *Corresponding author: *Nguyen Duc Tuan Email: ductuan@ump.edu.vn Pharmaceutical Sciences Asia © 2023 by Faculty of Pharmacy, Mahidol University, Thailand is licensed under CC BY-NC-ND 4.0. To view a copy of this license, visit https:// www.creativecommons.org/licenses/by-nc-nd/4.0/ ABSTRACT A solid-phase extraction (SPE) followed by gas chromatography-mass spectrometry (GC-MS) method was developed and validated for determination of seven amphetamine-type stimulants (ATSs) including amphetamine (AM), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylendioxyethylamphetamine (MDEA), para-methoxyamphetamine (PMA), 4-bromo-2,5- dimethoxyamphetamine (DOB), and ketamine (KET), norketamine (NKT) in human hair. Ten milligrams of human hair was washed by water and methanol followed by soaking in a solution of 1% hydrochloric acid in methanol for 18 hours. The analytes from the methanolic extract were isolated by a SPE procedure before being derivatized using heptafluorobutyric anhydride (HFBA) at 80°C for 40 minutes. The selected ion monitoring (SIM) method was used for the quantification of the derivatized compounds. The linear range was from 0.5-40 ng/mg for all of the analytes with the coefficient of determination (R 2 )>0.9971. The intra-day and inter-day accuracies were in the range of 93.63-112.40% and 94.70-110.20%, respectively. The intra-day and inter-day precision (RSD%) were in the range of 8.72 and 9.73, respectively. Limit of detection (LOD) and limit of quantitation (LOQ) for each analyte were less than 0.10 and 0.32 ng/mg, respectively. The recoveries were in the range of 75.18-89.30%. The GC-MS was used for the hair analysis on 51 subjects suspected to be ATSs and ketamine user. The average content of all the analytes was in the range of 1.14-12.70 ng/mg. On the basis of these results, the method was proved to be effective for identification and quantitation of above mentioned nine narcotics. Keywords: Amphetamine-type stimulants, Ketamine, GC-MS, Hair Research Article