Analytical method development and validation of RP-HPLC method for simultaneous estimation of N-acetyl cysteine and cefexime from its fixed dose combination

A simple novel validated isocratic reverse phase high performance liquid chromatographic method has been developed for the simultaneous estimation of N-acetyl cysteine (NAC) and cefexime from its fixed dose combination (FDC). The fixed dose combination of NAC and cefexime is used in the treatment of chronic obstructive pulmonary disease. Separation was achieved on Acclaim C₁₈ (150 mm x 4mm.) with 25 mM potassium dihydrogen phosphate (pH 2.7) and acetonitrile in the ratio 90:10 v/v. The mobile phase was pumped at 1mL/min and quantification was carried out at 220 nm using a UV detector. The retention time of NAC and cefexime was 2.7min and 11.47 min respectively. The method was validated as per ICH Q2R1 guidelines. The method demonstrated linearity from10-90 μg/ml and accuracy was between 101.16-101.96%. The precision of the method was less than 2% in all the cases. The method was further applied in the assay of marketed formulation.