New ranitidine analogues containing the 2-aminobenzimidazole moiety: in vivo and in vitro histamine H2-receptor blocking activity.
The paper reports the pharmacological profile of a new series of ranitidine analogues in which the diaminonitroethene group is replaced by the 2-amino-5(6)-substituted and unsubstituted benzimidazole moieties. These derivatives show a histamine H2-receptor blocking activity comparable to that of the model both in vitro (KB on atria 0.16-1.15 microM) and in vivo (ID50 on the perfused stomach of the anaesthetized rat from 0.34 to 4.10 mumol kg-1 i.v.). The results are consistent with the hypothesis that, at least in the ranitidine analogues, the "urea equivalent" moiety may be replaced by a polar group partially ionized at physiological pH without loss of H2-blocking activity.
D000818:Animals; D005744:Gastric Acid / Q000378:metabolism; D006168:Guinea Pigs; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects; D011896:Rana temporaria; D011899:Ranitidine / Q000031:analogs & derivatives*; D051381:Rats; D013329:Structure-Activity Relationship
D006635:Histamine H2 Antagonists; D011899:Ranitidine