Validation and Application of Quality Assurance Methods Developed for Artemisinin-Based Antimalarial Drugs to Assess the Quality of a Selection of Such Drugs Distributed in Accra, Ghana

A recently developed rapid semi-quantitative Thin Layer Chromatographic (TLC) assay method was applied in the determination of the existence of substandard or counterfeit artemisinin-based anti-malarial drugs in the Ghanaian market and also tested for its suitability for rapid assessment of drug quality prior to more rigorous analysis of any suspected counterfeit or substandard drugs. Three methods were employed – Basic Tests, Semi-quantitative TLC assay and High Performance Liquid Chromatographic (HPLC) assay. The basic tests showed that each drug contained the requisite active pharmaceutical ingredient (API). Out of the 49 samples (24 single dose and 25 fixed dose combination formulations) assayed by TLC, only 14 (28.6%) were found to comply with pharmacopoeial specifications. Out of the 24 single dose formulations, 9 of which had been found by the TLC assay likely to be within pharmacopoeial limits, only 4 were eventually found to be fully compliant by HPLC analyses. Two others were marginal. On the basis of the TLC assay, only 5 out of the 25 fixed dose combination formulations that are yet to be accurately assayed by HPLC, appear likely to meet pharmacopoeial specifications. The results of the semi-quantitative TLC technique compare favorably with those of the HPLC and hence the method can be used for rapid assessment of the quality of anti-malarial drugs. The results also indicate that the problem of distribution of substandard and possibly counterfeit artemisinin-based anti-malarial drugs exists in Ghana.