SR144528 is a drug that acts as a potent and highly selective CB<sub>2</sub> receptor inverse agonist, with a K<sub>i</sub> of 0.6 nM at CB<sub>2</sub> and 400 nM at the related CB<sub>1</sub> receptor. It is used in scientific research for investigating the function of the CB<sub>2</sub> receptor, as well as for studying the effects of CB<sub>1</sub> receptors in isolation, as few CB<sub>1</sub> agonists that do not also show significant activity as CB<sub>2</sub> agonists are available. It has also been found to be an inhibitor of sterol O-acyltransferase, an effect that appears to be independent from its action on CB<sub>2</sub> receptors.