Quantitative assay of ten brands of methyldopa tablets marketed in Lagos, Nigeria

Abstract

Hypertension is the most prevailing cardiovascular disease in the world as well as in pregnant women. It is also the commonest cardiovascular disease among Africans. The management of this disease includes the use of drugs that are safe and effective because of the peculiarities of the disease. The objective of this research was to carry out the quality assessment of methyldopa tablets, an antihypertensive drug marketed in Lagos, Nigeria. Ten different brands of methyldopa tablets were evaluated for weight variation, thickness, diameter, friability, hardness, disintegration and content of active ingredient according to the British Pharmacopoeia (2014) and United States Pharmacopoeia (2014) methods. The results obtained showed that all the brands (100%) tested fell within standard limits for the diameter, friability, and disintegration. Ninety (90) percent passed the weight variation test, thickness test and hardness test, while only 40% conformed to the standard limit for quantitative assay of active constituent. The results indicated that only 40% of the brands tested (including the innovator brand) passed all the tests carried out on them. This study has thus been able to show that some generic brands of methyldopa tablets available in the Nigerian market possess qualities below official recommendations, hence there is the need for constant monitoring of different brands of medications in the market to ensure their quality and safety.

Keywords: Physical tests, assay, hypertension, methyldopa, quality, tablets