ABSTRACT
Background: Antacids are weak bases which neutralize excess gastric acid and are commonly used by patients to obtain fast symptomatic relief from dyspepsia, heartburn, peptic ulcer, etc. The ability of an antacid to neutralize acid, is expressed as its acid neutralizing capacity (ANC) and this can vary from one brand to another. Acid reflux disorders are common conditions, which have resulted in the rise of antacid therapy and marketing of various brands of antacids based on the principles of neutralization of excess gastric acid. This study was carried out to determine the acid neutralizing capacity of twenty (20) randomly selected brands of antacid suspensions from various pharmacies in Benin metropolis and to determine the rationale for their interchangeability base on their ANC.
Method: The United States Pharmacopeia (USP) method of analysis of antacids was adopted, using acid-base titration (back/ indirect titration). The samples were coded A-T to avoid any bias in the study. All the sampled brands had at least 1 year to expiry as indicated on their label.
Results: All the antacids have shown the pH of between 8.76 and 7.30, indicating that the pH of all the antacids can be maintained, well above 3.5 which is the threshold for acidity of the stomach. Among all the antacids, the pH was found to be highest with sample M (8.76±0.04) and lowest with sample D (7.30±0.05). Also, the antacids have shown a flow time (in minutes), of between 70.11 and 0.27. The flow time was found to be highest with sample N (70.11±0.35) and lowest with sample A (0.27±0.01). The relative density measured, was highest with sample N (1.28) and lowest with sample B (1.03). Brand E had the highest ANC of 27.15 mEq/dose whiles brand C had the lowest ANC of 11.60 mEq/dose.
Conclusion: The acid neutralizingcapacity of all the selected antacid brands (available in pharmacies in Benin City) analysed, were within the US FDA requirement for the ANC of an effective antacid (≥5 mEq per dose). Brand E had the highest ANC, whiles Brand C had the lowest ANC. Rapid and effective acid neutralizing capacity of antacids are achieved with liquid antacids containing at least two of the following active pharmaceutical ingredients, which includes: Aluminium Hydroxide (Al(OH)3), Magnesium compounds (Magnesium Hydroxide (Mg(OH)2), Magnesium Trisilicate (Mg2Si3O8) and Magnesium Carbonate (MgCO3)), Malgadrate (AlHMgO5S+2) and Calcium Carbonate (CaCO3). Hence for acute symptomatic relief from acid reflux disorders, antacids containing the aforementioned active ingredients are essential.
