[Isomeric analysis of synthetic cannabinoids detected as designer drugs]

Recently, many psychotropic herbal products, named such as "Spice", were distributed worldwide via the Internet. In our previous study, several synthetic cannabinoids were identified as adulterants in herbal products being available in Japan due to their expected narcotic effects. Among those, two derivatives of Δ(9)-tetrahydrocannabinol (Δ(9)-THC), which is major psychotropic cannabinoid of marijuana, cannabicyclohexanol (CCH, 3-[2-hydroxy-4-(2-methylnonan-2-yl)phenyl]cyclohexan-1-ol) and CP-47,497 (3-[2-hydroxy-4-(2-methyloctan-2-yl)phenyl]cyclohexan-1-ol), have been controlled as designated substances (Shitei-Yakubutsu) under the Pharmaceutical Affairs Law since November 2009. CCH was detected together with its trans-form (1-epimer) in many herbal products, and CCH and CP-47,497 have two chiral centers in the structures. However, the pharmaceutical activities of the isomers of CCH have not been reported. This study presents chiral separations of CCH, its trans-form and CP-47,497 in the products using LC-circular dichroism (CD) and LC-MS analyses. The enantiomeric pairs of CCH, its trans-form and CP-47,497 were separated, respectively. Subsequently, the analyses of the herbal products showed that CCH and its trans-form existed as mixtures of enantiomers and the relative ratios of CCH and the trans-form enantiomers ranged from 42/58% to 53/47% and from 33/67% to 52/48%, respectively.