Difference spectroscopic and reverse phase HPLC methods for the estimation of cefdinir in pharmaceutical dosage forms
Two simple efficient and reproducible difference spectroscopic and reverse phase high performance liquid chromatographic methods have been developed for the estimation of cefdinir in pharmaceutical dosage forms. Difference spectroscopic method is based on the measurement of absorbance of cefdinir at maxima 265 nm and minima 230 nm. The measured value is the amplitude of maxima and minima between two eqimolar solutions of the analyte in different chemical forms, which exhibit different spectral characteristics. Beer's law was obeyed in the concentration range of 10 to 35 mg/ml. The second method, a High Performance Liquid Chromatography, was developed for the estimation of cefdinir, using 50 mM ammonium acetate (pH 3.0±0.1 adjusted with 10% phosphoric acid) and methanol (80:20% v/v) as the mobile phase with flow rate of 1 ml/min, and measuring the response at 285 nm. An external standard calibration method was employed for quantitation. Beer's law was obeyed in the concentration range of 15 to 125 mg/ml. The results obtained in the analysis of dosage forms agree well with the labelled contents.