The Quality and in Vitro Efficacy of Amoxicillin/Clavulanic Acid Formulations in the Central Region of Ghana

Aim: To assess the quality and in vitro efficacy of five brands of amoxicillin/clavulanic acid tablet, suspension and injectable preparations selected from pharmacies in the Central Region of Ghana. Method: Using a Stratified Representation Sampling method, forty preparations (tablets, suspensions and injectable powders) containing amoxicillin and clavulanic acid were sampled from nine different locations within the Central Region of Ghana. To determine drug quality, several procedures, namely, content assay, disintegration and dissolution testing were employed. In vitro drug efficacy was determined by comparing the Minimum Inhibitory Concentrations (MIC’s) obtained with published values. Results: All tablets passed the disintegration test, with disintegration time ranging between six (6) and fifteen (15) minutes. Analyses of all the tablets for drug content showed 100% failure (14 out of 14) for amoxicillin and 14% failure (2 out of 14) for clavulanic acid. Injectable formulations showed similar results. All four (4) samples analyzed for content failed the amoxicillin content assay (0 out of 4) but all passed clavulanic acid assay (4 out of 4). For tablet dissolution tests, there was a 93% (13 out of 14) pass rate for both amoxicillin and clavulanic acid. Content analysis of all suspension formulations involved twenty-two (22) samples from five (5) brands. Only 41% (9 out of 22) passed for both amoxicillin and clavulanic acid. All the other samples failed for either amoxicillin, clavulanic acid or both. Results obtained from drug quality tests were confirmed by in vitro efficacy tests against selected microorganisms. Conclusion: The samples were therefore not of good quality, since content assay is the most crucial test. It is hypothesized that