Development and Validation of a Stability-Indicating HPLC Method for Simultaneous Determination of Artemether and Lumefantrine in Tablet Formulations

Artemether-lumefantrine is the most widely recommended first-line treatment for uncomplicated falciparum malaria in Nigeria, and ensuring the quality of this combination product is central to national malaria elimination efforts. The co-determination of both active ingredients using a validated stability-indicating method is essential for accurate quality control across the medicine supply chain. This study developed and validated a reverse-phase HPLC method for the simultaneous quantification of artemether and lumefantrine in tablet dosage forms, with specific capability to resolve degradation products under accelerated stress conditions. Chromatographic separation was achieved on a C18 column using a gradient mobile phase of acetonitrile and ammonium acetate buffer. Method validation followed ICH Q2(R1) guidelines, evaluating specificity, linearity, accuracy, precision, limits of detection and quantification, and robustness. Forced degradation studies were conducted under acid, alkali, oxidative, photolytic, and thermal stress conditions. The method demonstrated linearity over 40 to 160% of nominal concentration for both analytes with correlation coefficients above 0.999. Intra-day and inter-day precision were within 2% RSD. Degradation products generated under stress conditions were resolved from the main peaks, confirming stability-indicating capability. The validated method was applied to twenty artemether-lumefantrine brands collected from health facilities in Ogun State, revealing two brands with potency below compendial specification. Keywords: HPLC validation, artemether, lumefantrine, stability-indicating method, method development.