Development and Validation of an HPLC Method for Simultaneous Determination of Antimalarial Drugs in Pharmaceutical Formulations

Ensuring the quality and potency of antimalarial pharmaceutical formulations is critical for effective malaria treatment in Nigeria, where substandard and counterfeit medicines represent a documented public health threat. This study developed and validated a rapid, selective, and sensitive reversed-phase high-performance liquid chromatography method for the simultaneous determination of artemether and lumefantrine, the most widely used artemisinin-based combination therapy in Nigeria, in tablet formulations. Method development involved systematic optimisation of the stationary phase, mobile phase composition, pH, flow rate, column temperature, and detection wavelength. The optimised method used a C18 column with a mobile phase of acetonitrile and 0.1 percent orthophosphoric acid in water at a ratio of 65:35, a flow rate of 1.2 mL/min, and UV detection at 210 nm. The method was validated according to ICH Q2(R1) guidelines for specificity, linearity, accuracy, precision, limit of detection, limit of quantification, and robustness. Linearity was demonstrated over the range of 1 to 200 micrograms per millilitre for both compounds, with correlation coefficients exceeding 0.999. Intraday and interday precision values were below 2 percent relative standard deviation. Recovery studies confirmed accuracy between 98.6 and 101.4 percent. The validated method was applied to twenty commercial artemether-lumefantrine formulations collected from pharmacies in Lagos and Abuja, identifying two samples with artemether content below 90 percent of the declared label claim. The method provides a reliable quality control tool for routine monitoring of antimalarial combination products in Nigeria.

Keywords: HPLC method validation, artemether, lumefantrine, antimalarial quality control, Nigeria