Stability-Indicating High-Performance Thin-Layer Chromatography Method Development and Validation for Topiroxostat in Bulk and Tablet Dosage Forms Using a Quality by Design Approach

A new, simple, rapid, accurate, and precise high-performance thin-layer chromatography (HPTLC) method has been developed for the estimation of topiroxostat in bulk and tablet dosage form. In this method, aluminum plates with precoated silica gel 60 F₂₅₄ were used as the stationary phase. The mobile phase consisted of ethyl acetate, toluene, methanol, and glacial acetic acid (5 : 4 : 1 : 0.1, v/v/v). The calibration plot showed good linearity in the range of 40–240 ng/spot with a coefficient of regression, r² of 0.994, with respect to peak area. Ishikawa (fishbone) diagram and failure mode effect analysis were used as risk assessment tools. The saturation time, band length, and volume of methanol were determined as critical method parameters and extensively optimized employing Box-Behnken design, with a focus on the retardation factor value as the critical analytical attribute. The method was validated according to the International Conference on Harmonization guideline Q2 (R1). The limits of detection and quantitation were 1.45 and 4.41, respectively. The percentage recovery was found to be 99.59%. The degradation study was carried out in acidic, basic, oxidative, neutral, dry heat, and photolytic conditions. Therefore, it was concluded that the developed HPTLC method can be applied for the identification and quantitative determination of topiroxostat in bulk and tablet dosage form.