AM-938

AM-938 (part of the AM cannabinoid series) is an analgesic drug which is a cannabinoid receptor agonist. It is a derivative of HU-210 which has been substituted with a 6β-(3-hydroxyprop-1-ynyl) group. This adds a "southern" aliphatic hydroxyl group to the molecule as seen in the CP-series of nonclassical cannabinoid drugs, and so AM-938 represents a hybrid structure between the classical and nonclassical cannabinoid families, with the 6-hydroxyalkyl chain rigidified with a triple bond. This gives AM-938 a greater degree of selectivity, so while it is still a potent agonist at both CB₁ and CB₂, it is reasonably selective for CB₂, with a K_i of 0.3 nM at CB₂ and 1.2 nM at CB₁, a selectivity of around four-fold.