Ro18-5362 is the less active prodrug of Ro 18-5364. Even at concentrations as high as 0.1 mM Ro 18-5362 fails to affect significantly (H++K+)-ATPase activity and associated proton translocation.
Marked differences are seen between Ro 18-5364 (sulfoxide) and Ro18-5362 (sulfide) with regard to inhibitory activity. Even at concentrations as high as 0.1 mM Ro18-5362 fails to affect significantly (H++K+)-ATPase activity and associated proton translocation[1]. The sulfoxide Ro 18-5364, a potential metabolite of the IND Ro18-5362, is a powerful inhibitor of gastric mucosal (H++K+)-ATPase, decreasing enzymatic activity with an apparent Ki of 0.1 μM[2].
[1]. Sigrist-Nelson K, et al. Ro 18-5364, a potent new inhibitor of the gastric (H+ + K+)-ATPase. Eur J Biochem. 1987 Jul 15;166(2):453-9. [2]. Sigrist-Nelson K, et al. Gastric (H+ + K+)-ATPase: modulation of the inhibitory properties of the novel potent antisecretagogue Ro 18-5364 by sulfhydryl reagents and nucleotides. FEBS Lett. 1986 Mar 3;197(1-2):187-91.