S-ethyl N-[4-(trifluoromethyl)phenyl]isothiourea

S-ethyl N-[4-(trifluoromethyl)phenyl]isothiourea (often abbreviated as EPIT or TFMPITU) is a small molecule that acts as a highly selective and competitive inhibitor of neuronal nitric oxide synthase (nNOS). It demonstrates strong selectivity for nNOS over other nitric oxide synthase isoforms, with a Ki of 0.32 μM for human nNOS and much weaker inhibition of inducible NOS (iNOS; Ki = 37 μM) and endothelial NOS (eNOS; Ki = 9.4 μM), corresponding to 115-fold and 29-fold selectivity for nNOS compared to iNOS and eNOS, respectively[1][3][4]. The compound has been used primarily in research settings to study the role of nNOS in physiological processes such as neurotransmission, blood pressure regulation, platelet aggregation, and immune responses. In animal studies, it has shown good blood-brain barrier penetration when administered intravenously[1][4]. There are no approved clinical indications or marketed formulations.

Other names

S-Ethyl-N-[4-(Trifluoromethyl)Phenyl]IsothioureaS-Ethyl N-(4-(trifluoromethyl)phenyl)isothioureaCarbamimidothioic acid, (4-(trifluoromethyl)phenyl)-, ethyl esterEthyl N′-[4-(trifluoromethyl)phenyl]carbamimidothioate