Determination of Phenyltetrahydroimidazothiazole Enantiomers (Levamisole/Dexamisole) in Illicit Cocaine Seizures and in the Urine of Cocaine Abusers via Chiral Capillary Gas Chromatography–Flame-Ionization Detection: Clinical and Forensic Perspectives

Author： Casale John F. Colley Valerie L. LeGatt Donald F.

Publisher： Oxford University Press

ISSN： 0146-4760

Source： Journal of Analytical Toxicology, Vol.36, Iss.2, 2012-03, pp. : 130-135

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Illicit cocaine laboratories in South America have been adding phenyltetrahydroimidazothiazole enantiomers (levamisole and/or tetramisole) to refined illicit cocaine for over 8 years. A chiral capillary gas chromatographic methodology is presented for phenyltetrahydroimidazothiazole enantiomer determination in illicit cocaine samples and in the urine of cocaine abusers. Illicit cocaine samples (N = 752) and urine specimens from cocaine abusers (N = 50) that contained phenyltetrahydroimidazothiazole were analyzed for enantiomeric composition. Legitimate commercial preparations of phenyltetrahydroimidazothiazole are either 100% levamisole or a 50:50 mixture of levamisole and dexamisole (tetramisole). Specimens that contain phenyltetrahydroimidazothiazole mixtures that are other than 50:50 preparations will be enhanced in one isomer over the other, and they are referred to as either “levamisole-enhanced” or “dexamisole-enhanced”. Cocaine samples were found to contain levamisole (N = 495, 66%), tetramisole (N = 143, 19%), and levamisole-enhanced enrichment (N = 114, 15%); urine specimens contained levamisole (N = 23, 46%), levamisole-enhanced enrichment (N = 10, 20%), and dexamisole-enhanced enrichment (N = 13, 26%). The toxicological and forensic aspects of these findings are discussed.