Preliminary in-vitro evaluation of marketed formulations for antacid activity

Background: Hydrochloric acid (pH 1.5-3.5) being the major component of gastric acid is produced by parietal cells of stomach. Its secretion is a complex and relatively energetically expensive process. The preservation of acidity of stomach is evidently important because of its implications in peptic and duodenal ulceration.Methods: In the present study, we attempted to compare the activity of 13 (F1-F13) antacid formulations (5-liquid, 4- quick releases and 4- tablets) by using acid-base neutralization studies. Preliminary antacid test (PAT) was performed to define whether the given formulation falls under the category of antacid wherein the pH of the antacid-acid (HCl) solution should be higher than pH of 3.5. The chosen antacids were further subjected to acid neutralizing capacity (ANC) (reaction between the sample of antacid and amount of acid neutralized by the formulation) and acid neutralizing potential (ANP) which explains the time duration during which a given sample of antacid can maintain pH above 3.5).Results: Out of the 13 samples tested, two formulations of pastels (F6, F12) were rejected as per the standard protocol of classifying formulations as antacids after screening for PAT. Sample F5 was found to have the highest ANC. F7 also showed highest ANC among the tablets tested. Also, F13 showed better ANC and ANP as in comparison to other quick releases.Conclusions: Digene products (F5, F7, and F13) showed better antacid properties. This data would provide insights into development of drug, comparison between antacids depending on their chemical formulation and determination of dosage to avoid plausible side effects.