Pyrolysis of UR-144, a synthetic cannabinoid, augments an affinity to human CB1 receptor and cannabimimetic effects in mice.

Drug abusers most often smoke 'herbal incense' as a cigarette or inhale it using a smoking tool. Smoking may cause pyrolysis of the drug and produce decomposed products of which biological effect has never been investigated. The synthetic cannabinoid UR-144 is known to undergo thermal degradation, giving a ring-opened isomer, so-called UR-144 degradant. The present study demonstrates by using UR-144 as a model drug that the smoke of burned UR-144 contains the UR-144 degradant. The UR-144 degradant showed approximately four fold higher agonist activity to human CB1 receptor and augmented hypothermic and akinetic actions in mice compared to UR-144. These results indicate that smoking behavior may increase psychological actions of the certain synthetic cannabinoids.