Endoscopic evaluations of potentially ulcerogenic drugs. A new in vivo porcine test model.

A new test model in living pigs is presented. The model is easy to manage and, in contrast with other test models, it is unnecessary to euthanize the animals. The animals keep their value and can be slaughtered later. We advise the use of only one period of 'pill-feeding', because more periods will stress the animals and probably inhibit normal weight gain. We suggest this model as the method of choice in the evaluation of local ulcerogenic effects of drug substances in oral pharmaceutical formulations. An endoscopic evaluation in vivo of the ulcerogenic effect of potassium chloride in different microencapsulated preparations, wax-matrix formulations, a liquid preparation, and a noncoated reference formulation showed one of the microencapsulated preparations to induce a significantly lesser degree of gastric mucosal damage than did all the other preparations. The gastric injury following a slow-release iron preparation and alprenolol (Aptine) was similar to that following the slow-release and the wax-matrix preparations of potassium chloride. Potassium chloride mixture caused gastric mucosal damage to the same extent as the other commonly used preparations of potassium chloride. Potassium chloride supplement causes gastric mucosal damage, but the results from the present in vivo porcine test model suggest that the severity of the injury seems to be a matter of appropriate drug formulation.