PipISB

PipISB is a drug used in scientific research which acts as a potent and selective inverse agonist of the cannabinoid receptor CB₁. It is highly selective for the CB₁ receptor over CB₂, with a K_d at CB₁ of 1.5nM vs over 7000nM at CB₂, has good blood-brain barrier penetration, and can be conveniently radiolabelled with either ¹¹C or ¹⁸F, making it useful for mapping the distribution of CB₁ receptors in the brain.