Evaluation of Antacids in Man Using the Heidelberg Capsule

Abstract

Thirteen commercially available antacids in tablet form were tested in healthy young volunteers using a transistorized miniature telemetric device (Heidelberg Capsule). After the radio transmitter capsule was swallowed, an alkali response test was performed, and two tablets of the antacid to be tested then administered. The recorded pH versus time curves were evaluated for onset of action defined as increase of pH to a value above 3, the maximum pH obtained, and the area under the pH versus time curve after the alkali response test and after administration of the antacid. For the latter one two areas were determined, the one above the base line and that above pH 5.5. It has been determined that to be effective in ulcer patients an antacid should bring the gastric pH to a value of 5.5 or above at which point the proteolytic enzymes are inactive. Only 9 of the 13 preparations resulted in pH above 5.5. Dividing the areas under the curve above the base line after administration of the antacid by the area under the curve obtained after the alkali test the extent of antacid capacity (E.A.C.) or “potency” of the preparation is obtained. Only four of 13 antacids resulted in an E.A.C. of more than twice that found during the alkali test.