Development and Validation of a Stability‐Indicating HPLC‐UV Assay for Quantification of Tafenoquine Succinate in a Novel Paediatric Antimalarial Formulation

Tafenoquine, an 8-aminoquinoline antimalarial, represents a promising advancement in combating malaria, but its bitter taste and lack of paediatric formulations hinder effective treatment for children. In response, we have formulated a chocolate-based chewable tafenoquine tablet for paediatric use. A rapid, stability-indicating high-performance liquid chromatography method with ultraviolet detection was developed and validated for tafenoquine succinate quantification. Tablet samples were extracted with 85% methanol and analysed on a Waters XBridge C18 (150 × 4.6 mm, 5 μm) column using an isocratic mobile phase of 50 mM potassium dihydrogen orthophosphate buffer (pH 4.5) and acetonitrile (40:60, v/v). Detection was at 254 nm, with a retention time of 4.3 min. The method was linear over 0-313.6 μg/mL (R² ≥ 0.999) with limits of detection and quantification of 2.22 and 6.73 μg/mL, respectively. Precision (RSD 0.15%-1.35%) and accuracy (101.48%-101.90%) met International Council for Harmonisation Q2 (R2) criteria. Forced degradation showed tafenoquine's susceptibility to acidic (29.33%), basic (18.83%), photolytic (complete degradation by day 14), and oxidative (8.33%) stress, with complete chromatographic separation from degradation products. This robust, rapid and low-cost assay is suitable for routine content and stability testing, is adaptable to other tafenoquine formulations and can be further applied to clinical settings.