Innovative Quality by Design Approach for Development of Green Micellar HPLC Method for Simultaneous Determination of Atorvastatin and Amlodipine

The combined implementation of quality by design principles and green analytical chemistry leads to development of green micellar HPLC method for analysis of atorvastatin calcium and amlodipine besylate in binary mixtures and in their tablet dosage forms within 8 min. A two-level fractional factorial design was implemented for screening of different method parameters affecting chromatographic responses. Box-Behnken design was then used to study and optimize the most critical parameters. The optimum chromatographic conditions obtained from Box-Behnken design involved the use of a mixture of 0.17 M sodium dodecyl sulfate solution adjusted to pH 2.9 and 10%v/vn-butanol as mobile phase at a flow rate of 1.5 mL min(-1)and column temperature kept at 45 oC. The stationary phase was X-Bridge (TM) (150 mm x 4.6 mm, 5 mu m) column. The fluorescence detection was programmed at 276/378 nm (excitation/ emission) for the first 5 mins for atorvastatin then switched to 366/442 nm (excitation/emission) for amlodipine. A linear response was obtained over the ranges of 0.2-25 mu g mL(-1)for both drugs. The proposed method was validated and successfully implemented for the simultaneous determination of cited drugs in their different tablet dosage forms. The method was additionally applied to content uniformity testing according to the official guidelines. The application of quality by design principles and green analytical chemistry results in development of robust green method with less trial and error experiments.