What is "pipisb"

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