Quality Assessment of Twenty Brands of Sulfadoxine-Pyrimethamine tablets marketed in Mainland

Abstract

Globally, malaria remains the most important health care problem and is estimated to be responsible directly for about 3000 deaths a day worldwide. Sulphadoxine-Pyrimethamine (SP) is a combination therapy for serious malaria infections especially in areas where other medicines may not work. Due to the inhibition effects of the combination drugs at 2 different steps in the biosynthesis of tetrahydrofolate, the administration of SP results in a synergistic action against susceptible plasmodia. The low quality of many antimalarial formulations may be responsible for the resistance posed by Plasmodium strains against the drug. This study was focused at investigation of physicochemical parameters of 20 brands of SP tablets sampled from reputable pharmacy stores within the mainland area of Lagos, Nigeria. Physicochemical tests were conducted according to standard procedures specified in pharmacopoeia monographs, while dissolution and chemical assay were carried out using dissolution apparatus USP 2 and samples were analysed with UV-spectrophotometer and HPLC respectively. Results show no major discrepancies observed for uniformity of shape, size, color and all the brands assayed passed the visual inspection tests for authenticity of packaging materials. Hardness ranged from 5.76-8.74 kg/cm2, friability from 0.18-1.60 %, while the mean disintegration times ranged from 4.3-17.7 minutes and 95% of the brands conformed to official specified values for the physicochemical parameters. In this study, all the brands assayed conform to official USP 2013 purity range of 90-110% and passed the chemical assay for pyrimethamine, while 70% of the brands passed the chemical assay for sulphadoxine content. In this study, sulphadoxine generally gave a better release than pyrimethamine under the dissolution conditions, while 20% of brands assayed with mean release ranging from 50.9-58.7% at 30 minutes failed the dissolution tests for both APIs, 80% of the brands, having released ≥ 60% of the labeled amount of drug at 30 minutes, complied with the standard dissolution rates for active pharmaceutical ingredients. The result of this study indicates that the registration process and post-market surveillance in the country is having a significant impact as none of the brand assayed could be considered of very poor quality.Keywords: Pyrimethamine, sulphadoxine, physicochemical, dissolution, spectrophotometer