New validated methods for the simultaneous determination of two multicomponent mixtures containing guaiphenesin in syrup by HPLC and chemometrics-assisted UV-spectroscopy

High pressure liquid chromatographic (HPLC) and spectrophotometric methods are developed for the determination of two multicomponent mixtures containing guaiphenesin, dextromethorphane hydrobromide, and sodium benzoate together with either phenylephrine hydrochloride, chlorpheniramine maleate, and butylparaben (mixture 1) or ephedrine hydrochloride and diphenhydramine hydrochloride (mixture 2). The HPLC method depended on using an ODS column with mobile phase consisting of acetonitrile -10 mM potassium dihydrogen phosphate, pH 2.7 (40 : 60 v/v) containing 5 mM heptane sulfonic acid sodium salt (for mix 1) and a cyanopropyl column with mobile phase consisting of acetonitrile 212 mM ammonium acetate, pH 5 (40 : 60 v/v) (for mix 2) and UV detection at 214 nm. The cyanopropyl column is much less hydrophobic, less sterically restricted to the penetration of bulky solute