Simultaneous Spectrophotometric Determination of Diphenhydramine, Benzonatate, Guaifenesin and Phenylephrine in Their Quaternary Mixture Using Partial Least Squares with and without Genetic Algorithm as a Powerful Variable Selection Procedure

Diphenhydramine HCl, benzonatate, guaifenesin and phenylephrine HCl are coformulated together in Bronchofree TM capsule in the ratio of 2.5:10:10:1 respectively. Literature review showed only one reported HPLC method for this mixture. Simultaneous chemometricassisted spectrophotometric analysis of the multi-component dosage form has been carried out using two chemometric methods. These methods includes partial least squares (PLS-1) and PLS-1 proceeded by genetic algorithm (GA-PLS). Results demonstrated the efficiency of the two methods as quantitative tool of analysis of the four components without any interference of the excipient added, that eliminates the need for preliminary extraction of analytes from the pharmaceutical formulation. The four analytes were determined precisely using the afore-mentioned methods in an independent data set as well as in dosage form after optimization of the experimental conditions.Both methods are robust,accurate and precise in addition to their remarkable simplicity in comparison to other sophisticated techniques such as HPLC.