Determination of artemether and lumefantrine in anti-malarial fixed-dose combination tablets by microemulsion electrokinetic chromatography with short-end injection procedure

BACKGROUND: Artemether-lumefantrine (AL) combination therapy is now the most used anti-malarial treatment in the world. Quality control of AL formulations is still a major challenge in developing countries. Until now, only liquid chromatographic methods have been reported in the literature for their analysis. Capillary electrophoretic methods, which present various advantages (low price of capillary, low volumes of electrolyte consumption), may be an alternative to liquid chromatography methods. In this paper, a reliable method was developed and validated for the determination of AL in commercial fixed-dose combination tablets commercialized in Côte d’Ivoire. METHODS: Artemether and lumefantrine were determined by microemulsion electrokinetic chromatography using short-end injection procedure. The two analytes were extracted from tablets by acidified methanol. Pyrimethamine was used as internal standard. Separation was carried out in an uncoated fused silica capillary, 30 cm long × 50 μm internal diameter, using an effective length of 10 cm and a microemulsion composed of octane, butanol, sodium dodecyl sulfate and borate buffer as background electrolyte, a - 500 V.cm(-1) electric field and a detection wavelength of 214 nm. RESULTS: Artemether, lumefantrine and pyrimethamine were separated in 6 min. The method was reliable with respect to selectivity towards formulation excipients, linearity of the response function (r(2) > 0.998), recovery studies from synthetic tablets (in the range 99–101%), repeatability (relative standard deviation 1–3%, n = 7 analytical procedures). Application to four commercial formulations containing 20/120 mg of AL per tablet gave a content in good agreement with the declared content. However, the electropherogram of one tablet formulation showed the presence of an ingredient which was not declared. CONCLUSION: The developed MEEKC method can be proposed as an alternative method to liquid chromatography for the determination of artemether and lumefantrine in fixed-dose combination tablet formulations.