ABSTRACT

The increasing number of reports of sub-therapeutic responses elicited by many essential medicines, even at their therapeutic doses, including those which are considered as first-choice medications in the treatment and management of various disease conditions, have raised questions about the quality of these medicines available to both healthcare professionals and patients. In this study, methyldopa, which is one of the most widely used drug in the treatment of chronic hypertension in pregnant women, was subjected to quality assessment using quality parameters for tablets, such as weight variation, active content/drug assay, disintegration time, tablet hardness and friability. Six (6) different brands of methyldopa 250 mg tablets (A, B, C, D, E and F) commercially available in Benin-City, Edo State, Nigeria, were evaluated for this study and the result obtained for each test was compared to pharmacopoeial specifications. While brands A, D, E and F satisfactorily passed all the quality assessment tests, brands B and C failed at least one quality test. The active drug content/drug assay results for brand B (86.87 %w/w) and brand C (79.2% w/w) showed that they fell out the USP specification for methyldopa (90.0-110.0 % of the labeled content) using the USP non-aqueous titration method. Although some patient-specific factors may also contribute to this health issue, however, conducting post-marketing assessment of the quality of these medicines to ascertain whether they meet pharmacopoeial standards or not, represents a huge step in determining the extent to which the quality of essential medicines is implicated in contributing to health challenges in the country, and in the world at large.