FRG8701 is a new Histamine H2-receptor antagonist with an IC50 of ranging from 0.25 to 0.43 μM.

H2 receptor:0.25 to 0.43 μM

The inhibitory potency of FRG8701 is almost the same as that of famotidine and approximately 33 times greater than that of cimetidine.Positive chronotropic response to histamine at 10-5 M is dose dependently inhibited by FRG8701 (FRG-8701) famotidine or cimetidine;?and the IC50 values of FRG8701, famotidine and cimetidine are 3.3, 3.0 and 108.6 (×10-7M), respectively.

Other necrotizing agents-induced gastric lesions are also inhibited by treatment of FRG8701. The oral ED50 values against the lesions range from 1.1 to 9.4 mg/kg. FRG8701, given orally, dose-dependently prevents the development of gastric lesions induced by stress and indomethacin. Duodenal ulcer induced by mepirizole is also inhibited with FRG8701. The ED50 values of FRG8701 for each ulcer model range from 1.7 to 6.9 mg/kg.In the pylorus-ligated (4 hr) rats, each drug, given intraduodenally, dose-dependently inhibits the total acid output.?FRG8701 at 10 or 30 mg/kg, given orally or intraperitoneally, significantly prevent the formation of the gastric mucosal lesions induced by 0.4 N HCI+50% ethanol (HCI?ethanol).