Sorbitol-accumulating pyrimidine derivatives.

The novel compounds SDI 157 (2-methyl-4(4-N,N-dimethylaminosulfonyl-1-piperazino)pyrimid ine, CAS 131816-54-1) and SDI 158 (2-hydroxymethyl-4-(4-N,N-dimethylaminosulfonyl-1- piperazino) pyrimidine, CAS 140687-51-0) have been found to be inhibitors of sorbitol dehydrogenase. In normal and diabetic animals both compounds induced a dose-dependent increase of tissue sorbitol, especially in the peripheral nerve, without alteration of the blood glucose. In contrast to SDI 158, SDI 157 does not act in vitro. However, in the isolated perfused rat liver SDI 157 induced a high sorbitol release and plasma samples of animals treated with SDI 157 induced a sorbitol accumulation in vitro in erythrocytes like SDI 158. SDI 157 seems to be a prodrug. In accordance with the polyol theory, the chronic administration of SDI 157 to diabetic rats accelerated the cataract development and depleted the lens of total and oxidized glutathione. Surprisingly, however, it accelerated the motor nerve conduction velocity in normal and diabetic rats, normalized the glomerular filtration rate in diabetic rats and did not induce retinal capillary lesions in normal rats or aggravate those in diabetic rats. At single oral doses up to 100 mg/kg, SDI 157, was well tolerated by diabetic and normal rats. Except for a reduction of drinking water consumption, the chronic administration of SDI 157 in drinking water at doses up to 100 mg/kg per day had no side effects in normal, diabetic and galactoselfructose-rich diet rats.

2-[(2-pyridylmethyl)sulfinyl]-1H-thieno[3,4-d]imidazoles. A novel class of gastric H+/K(+)-ATPase inhibitors.

2-[(2-Pyridylmethyl)sulfinyl]thienoimidazoles were synthesized and investigated as potential inhibitors of gastric H+/K(+)-ATPase. The [3,4-d] isomers of the two possible thienoimidazole series were found to be potent inhibitors of gastric acid secretion in vitro and in vivo. Structure-activity relationships indicate that especially lipophilic alkoxy, benzyloxy, and phenoxy substituents with additional electron-demanding properties in the 4-position of the pyridine moiety combined with an unsubstituted thieno[3,4-d]imidazole lead to highly active compounds with a favorable chemical stability. Various substitution patterns in the thieno[3,4-d]imidazole moiety result in lower biological activity. The heptafluorobutyloxy derivative saviprazole (HOE 731, 5d) was selected for further development and is currently undergoing clinical evaluation. Comprehensive pharmacological studies indicate a pharmacodynamic profile different to omeprazole, the first H+/K(+)-ATPase blocker introduced on the market.

A substituted thieno[3.4-d]imidazole versus substituted benzimidazoles as H+, K+-ATPase inhibitors.

S 3337, 2-(2-ethylaminobenzylsulfinyl)-5,6-dimethoxybenzimidazole, and S 1924, 2-(5-methyl-2-picolylsulfinyl)-1H-thieno[3.4-d]imidazole, are members of new classes of H+, K+-ATPase inhibitors. Their effects on H+, K+-ATPase and 14C-aminopyrine uptake in gastric glands were studied as well as in vivo in pylorus-ligated rats, stomach-lumen-perfused rats and Heidenhain pouch dogs. Their inhibitory effects were compared with the effect of omeprazole. In pylorus-ligated rats the two compounds showed a similar effectiveness as omeprazole. In stomach-lumen-perfused rats and in particular in Heidenhain pouch dogs, S 3337 was clearly less effective than omeprazole, while S 1924 was similarly effective in all in vivo models and in the H+, K+-ATPase assay as omeprazole. The difference in potency between S 1924 and omeprazole on 14C-aminopyrine uptake in gastric glands can be explained by the lower pKa value of S 1924 (3.4) than that of omeprazole (4.0). Additionally, this study shows that there was no correlation between the effects in rats, particularly in pylorus-ligated rats, and in dogs for the H+, K+-ATPase inhibitors tested. It is concluded from this study that substituted thieno[3.4-d]imidazoles represent a new class of potent gastric acid inhibitors.