Central Composite Design Expert-Supported RP-HPLC Optimization and Quantitative Evaluation of Efonidipine Hydrochloride Ethanolate & Chlorthalidone in Tablet.

Central composite design based RP-HPLC method optimization for the synchronized analysis of Efonidipine Hydrochloride Ethanolate (EFE) and Chlorthalidone (CHL) in tablet. The effective separation was performed using Inertsil ODS C18 column (250 × 4.6 mm, 5 μm), PDA detector with 0.05 M KH2PO4 Buffer (pH 4.5): Acetonitrile (40:60%v/v) mobile phase. Independent variables were investigated include the concentration of KH2PO4 (X1) and flow rate of mobile phase (X2). Based on responses obtained (retention time, resolution and tailing factor), the optimum condition selected was X1 = 40% and X2 = 1 ml/min. Optimized HPLC condition was validated by assessing validation parameters and it meets the acceptance criteria set by ICH. The linear calibration curve was found to be in the quantity range 6.25-18.75 and 20-60 μg/ml Assay of drugs was 100.94 and 100.06% for CHL and EFE. The validated RP-HPLC-PDA method can be used for routine analysis of EFE and CHL in tablet.