Azamulin is a derivative of the antibiotic pleuromutilin. It is a highly selective inhibitor of the CYP3A family (IC50 = 0.03-0.24 μM as reported in Stresser et al., DMD, January 2004 vol. 32 no. 1 p105-112). Azamulin is a 15 and 13 fold more potent inhibitor of CYP3A4 compared to CYP3A5 or CYP3A7 respectively making it very useful for CYP3A4 activity assays and can be used as a benchmark in CYP3A4 inhibitor screening assays. It is at least 100 fold selective over other CYP isoforms (except CYP2J2 ~ 50-fold). MW: 478.65. Purity ≥98% by HPLC