Characterization of Some Impurities in Two Brands of Artesunate Tablets

Abstract

antimalaria in malaria endemic areas of the world by World Health Organization (WHO) to ensure high cure rates of plasmodium falciparium malaria and to reduce the spread of drug resistance. During a quality assessment of Artesunate tablets found in Nigerian markets, Thin Layer Chromatography (TLC) revealed an unknown impurity spot which exceeded the identification thresholds of ICH guidelines. This work has detected and identified two degradation products and other impurities that may be present using analytical techniques that are readily available in this region. Two brands of Artesunate tablets alongside Artesunate and dihydroartemisinin authentic reference standard tablets were extracted with methanol and the extracts subjected to Gas Chromatographic-mass spectrometric (GC-MS) and confirmatory TLC Procedures. The GC-MS spectra of the samples when compared to that of the reference standard revealed high levels of succinic acid in both brands; this was confirmed by TLC which also revealed Dihydroartemisinin (DHA) to be the other degradation product. Quantitative analysis revealed the level of succinic acid in the degraded samples to be 28.7%w/w and 26.42%w/w. The results suggest an acid-catalyzed hydrolytic degradation of artesunate which resulted in a chain reaction in the presence of residual moisture in the tablets. The incomplete conversion of dihydroartemisinin to artesunate during the synthesis of the starting raw material is also a possible source of these impurities