O-2545 is an analgesic cannabinoid derivative created by Organix Inc. for use in scientific research. Unlike most cannabinoids discovered to date, it is water-soluble, which gives it considerable advantages over many related cannabinoids. It has high affinity for both CB<sub>1</sub> and CB<sub>2</sub> receptors, with K<sub>i</sub> values of 1.5 nM at CB<sub>1</sub> and 0.32 nM at CB<sub>2</sub>.