Development of Acid-Neutralization and In Vitro Dissolution to Evaluate the Overall Quality of Compound Aluminum Hydroxide Tablets

Background: Compound Aluminum Hydroxide Tablets (CAHTs) are widely used in the Chinese domestic market, and strict quality control is required to ensure their clinical efficacy. Purpose: In this study, we established a comprehensive strategy of acid-neutralization, in vitro dissolution and an assay of magnesium trisilicate to evaluate the overall quality and monitor the consistency of CAHTs. Methods: The acid-neutralization profiles of 38 batches of CAHTs were generated using the dissolution and release method III (the cup method, the Chinese pharmacopeia) combined with potentiometric titration. To directly reflect the disintegration and release process of the preparation, we optimized the sample pretreatment method by omitting the grinding step to determine the profiles of complete tablets. In addition, in vitro dissolution was conducted in the hydrochloric acid medium at pH 1.0 by using the assay of magnesium trisilicate through a validated approach of Flame Atomic Absorption Spectrophotometry (FAAS) to evaluate the similarity of the dissolution profiles. Results: Acid-neutralization tests showed that the quality of the samples from manufacturers B and F was poor. In vitro dissolution experiments showed that the samples from manufacturer A had the highest similarity with the reference preparation, which indicated their good quality consistency. Besides, the optimized acid-neutralization method had the advantage of simple operation and enabled direct characterization of pharmacodynamics in the quality consistency evaluation of antacids. Conclusion: A successful synthetic evaluation strategy was established to assess the overall quality of CAHTs, which demonstrated that the improvement in the quality of this formulation is imperative.