Quality by Design Determination of Diclofenac Potassium and its Impurities by High-Performance Liquid Chromatography

Abstract

A liquid chromatography method is reported for the determination of diclofenac potassium and its impurities using Quality by Design criteria. Central composite design was used for the investigation of the influence of critical parameters on performance that included the methanol concentration in the mobile phase, the pH of the aqueous phase, and the potassium dihydrogen phosphate concentration in the aqueous phase. Mathematical models enabled theoretical examination of experimental space to achieve maximal separation in minimal analysis time. A Monte Carlo simulation was used to evaluate the risk of uncertainty in model predictions, to adjusting process parameters, and to identify design space. Fractional factorial design was employed for robustness testing and method was fully validated. Optimal conditions were a C18 150mmx4.6mm, 5 mu m particle size column; a methanol -68.3mmolL(-1) potassium dihydrogenphosphate (68.7:31.3, v/v) mobile phase at pH 3.0, a flow rate of 1mL min(-1), a column temperature of 25 degrees C, and ultraviolet detection at 254nm.