The high-Performance Analytical Liquid Chromatography (HPLC) method (AQbD) for routine analysis of Gemfibrozil in dosage form was developed in column C18 using an experimental design. The central composite design (CCD) was adopted in evaluating the responses and robustness of the method. In the project, the combined effect of buffer pH, % organic phase and flow rate, each at five levels, was selected for responses such as retention time and number of theoretical plates, then interpreted and optimized statistically with the help of the surface methodology of response and therefore of the analysis of the constructed models and of the outline graphs was obtained. Acetonitrile: phosphate buffer (pH-4) (59: 41% v / v) as eluent at a flow rate of 1.0ml/min was found to be the optimal condition for obtaining the desired answers.

The present study examines simultaneous multiple response optimization using desirability function for the development of an HPTLC method to detect esomeprazole magnesium trihydrate and levosulpiride in pharmaceutical dosage form. HPTLC separation was performed on aluminium plates pre-coated with silica gel 60 F254 as the stationary phase using ethyl acetate:methanol:toluene:ammonia (7:1.5:1.5:0.1% v/v/v) as the mobile phase. Full factorial design applied for the optimization of degradation condition. Esomeprazole magnesium trihydrate and levosulpiride were subjected to acid, alkali hydrolysis, oxidation and photodegradation. Experimental full factorial design has been used during forced degradation to determine significant factors responsible for degradation and to optimize degradation conditions reaching maximum degradation. 32 and 23 full factorial design has been used for optimization of chromatographic condition in acid and base degradation study, respectively. Quantification was achieved based on a densitometric analysis of esomeprazole magnesium trihydrate and levosulpiride over the concentration range of 800-4000 ng/band and 1500-7500 ng/band, respectively at 254 nm. The method yielded compact and well-resolved bands at Rf of 0.70 ± 0.02 and 0.32 ± 0.02 for esomeprazole magnesium trihydrate and levosulpiride, respectively. The linear regression analysis for the calibration plots produced r2 = 0.9967 and r2 = 0.9981 for esomeprazole magnesium trihydrate and levosulpiride, respectively. Method is validated as per ICH (Q2)R1 guideline.