Monitoring of herbal mixtures potentially containing synthetic cannabinoids as psychoactive compounds.

Herbal mixtures like 'Spice' with potentially bioactive ingredients were available in many European countries since 2004 and are still widely used as a substitute for cannabis, although merchandized as 'herbal incense'. After gaining a high degree of popularity in 2008, big quantities of these drugs were sold. In December 2008, synthetic cannabinoids were identified in the mixtures which were not declared as ingredients: the C(8) homolog of the non-classical cannabinoid CP-47,497 (CP-47,497-C8) and a cannabimimetic aminoalkylindole called JWH-018. In February 2009, a few weeks after the German legislation put these compounds and further pharmacologically active homologs of CP-47,497 under control, another cannabinoid appeared in 'incense' products: the aminoalkylindole JWH-073. In this paper, the results of monitoring of commercially available 'incense' products from June 2008 to September 2009 are presented. In this period of time, more than 140 samples of herbal mixtures were analyzed for bioactive ingredients and synthetic cannabimimetic substances in particular. The results show that the composition of many products changed repeatedly over time as a reaction to prohibition and prosecution of resellers. Therefore neither the reseller nor the consumer of these mixtures can predict the actual content of the 'incense' products. As long as there is no possibility of generic definitions in the controlled substances legislation, further designer cannabinoids will appear on the market as soon as the next legal step has been taken. This is affirmed by the recent identification of the aminoalkylindoles JWH-250 and JWH-398. As further cannabinoids can be expected to occur in the near future, a continuous monitoring of these herbal mixtures is required. The identification of the synthetic opioid O-desmethyltramadol in a herbal mixture declared to contain 'kratom' proves that the concept of selling apparently natural products spiked with potentially dangerous synthetic chemicals/pharmaceuticals is a continuing trend on the market of 'legal highs'.