EXPERIMENTAL DESIGN APPROACH TO OPTIMIZATION OF THE NEW COMMERCIAL RP-HPLC DISCRIMINATION CONDITIONS FOR THE ESTIMATION OF PARACETAMOL AND ZALTAPROFEN IN PHARMACEUTICAL FORMULATION

A simple, rapid, RP-HPLC method developed for the simultaneous estimation of paracetamol and zaltaprofen in commercial pharmaceutical formulation by applying Derringer’s desirability function. The dependent variables such as Capacity factor of first peak, α value and retention time of tR₃ as the responses with three important independent factors of organic phase composition, pH of mobile phase and flow rate, were used to design mathematical models. The experimental responses were fitted into a second order polynomial and the three responses were simultaneously optimized. The optimum assay conditions were: Methanol-Water (pH 3.5 adjusted with 10 % O-phosphoric acid) (60:40 % v/v)as the mobile phase and at a flow rate of 0.98 ml/min. while using this optimum condition, baseline separation with a minimum resolution of 2.0 and a run time of less than 10 min were achieved. This method showed good agreement between the experimental data and predictive value throughout the studied parameter space. The optimized assay condition was validated according to ICH guidelines to confirm specificity, linearity, accuracy and precision.