Stability indicating methods for the quantitative determination of pseudoephedrine HCl and guaifenesin and dextromethorphan HBR in a cough syrup using HPLC

ABSTRACT

The determination of three active ingredients in a multicomponent pharmaceutical product by HPLC using two columns is reported. Guaifenesin and dextromethorphan HBr were separated and quantitated simultaneously in a cough syrup using an isocratic reversed phase system. The mobile phase was 45% [v/v] aqueous methanol with ammonium formate as buffer [PH 4.3]. the range of concentrations used in the determination of guaifenesin and dextromethorphan HBr were 202-363 mg/100ml and 30-54 mg/100 ml, respectively. A separate method was developed for the determination of pseudoephedrine HCI using a normal phase system. The mobile phase was 80% [v/v] aqueous ethanol with ammonium acetate as buffer [pH 7.3]. the range of concentrations used in the determination of pseudoephedrine HC1 was 60-108 mg/100 ml. Both methods proved to be repeatable, reproducible and stability indicating