A highly potent and selective inhibitor of the type 5 17-β-hydroxysteroid dehydrogenase AKR1C3 (IC₅₀ = 88 nM). Displays >100-fold selectivity against AKR1C1, AKR1C2 and AKR1C4. Does not display any COX (cyclooxygenase) inhibition at 10 µM in whole blood assay.