Detection of phentermine in hair samples from drug suspects

Phentermine (PT) has been widely used as an anti-obesity drug. This drug has to be used with caution due to its close resemblance with amphetamines in its structure and toxicity profile. Recently, PT is in distribution by illegal modes and is found to be available through sources such as the internet, thus their misuse and/or abuse is threatening to be a serious social issue. In the present study, 32 cases of drug suspects were observed for PT abuse, detected using hair samples for drug analysis. PT and other amphetamines, such as methamphetamine (MA), amphetamine (AP), 3,4-methylenedioxyamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA), were extracted using 1% HCl in methanol for 20 h at 38°C. The extracts were derivatized with trifluoroacetic anhydride (TFAA) and analyzed using gas chromatography/mass spectrometry (GC/MS). Among the 32 cases of PT abuse, MA and its main metabolite, AP were identified in seven cases and MDMA and its main metabolite, MDA were detected in two other cases.