Famotidine-13C-d3 is intended for use as an internal standard for the quantification of famotidine by GC- or LC-MS. Famotidine is a histamine H2 receptor antagonist with a Ki value of 12 nM in fractionated guinea pig cerebral cortex membranes.1 It is selective for H2 over H1 and muscarinic receptors (Kis = 4 and 28 µM, respectively, in bovine cerebral cortex).2 Famotidine inhibits histamine-induced acid secretion in isolated canine parietal cells (IC50 = 0.6 µM).3 It also suppresses histamine-induced gastric acid secretion in dogs when administered orally and in anesthetized rats when administered intraduodenally (ID50s = 10 and 400 µg/kg, respectively).3 Formulations containing famotidine have been used in the treatment of ulcers, gastroesophageal reflux disease (GERD), and heartburn, as well as to decrease the risk of gastrointestinal toxicity associated with non-steroidal anti-inflammatory drugs (NSAIDs).
1.Gajtkowski, G.A., Norris, D.B., Rising, T.J., et al.Specific binding of 3H-tiotidine to histamine H2 receptors in guinea pig cerebral cortexNature304(5921)65-67(1983) 2.Kubo, N., Shirakawa, S., Kuno, T., et al.Antimuscarinic effects of antihistamines: Quantitative evaluation by receptor-binding assayJpn. J. Pharmacol.43(3)277-282(1987) 3.Nagaya, H., Inatomi, N., and Satoh, H.Differences in the antisecretory actions of the proton pump inhibitor AG-1749 (lansoprazole) and the histamine H2-receptor antagonist famotidine in rats and dogsJpn. J. Pharmacol.55(4)425-436(1991)