Methods for the assessment of antacids. In-vitro and in-vivo investigations with gastric aspiration.

In-vitro investigations offer a simple and reproducible method to estimate antacid potency and reactivity. The acid-neutralizing capacity, the onset and duration of action and the buffering capacity of an antacid can be determined by these tests. In vivo- tests can, to some extent, approximate in-vivo conditions and the in-vivo potency of an antacid can be predicted with reasonable accuracy by means of in-vitro tests. In vitro tests are needed to control and standardize various antacid preparations which vary in composition and content. In-vivo tests are needed to assess antacid potency in various physiological conditions and to study the principles of an optimal antacid therapy. The most conventional of these methods has been the aspiration technique. pH-recording by means of repeated gastric aspirates is more laborious than in other methods but will give reliable results when a proper and careful aspiration technique is used.