Development of Indirect Spectrophotometric Method forQuantification ofCephalexin in Pure Form and CommercialFormulation Using Complexation Reaction

A simple,accurate and indirect spectrophotometric method was developed for the quantification ofcephalexin in pure form and pharmaceutical products using complexation reaction.The developedmethod is based on the oxidation of the cephalexin with Fe3+in acidic medium. Then 1, 10-phenanthroline reacts with Fe2+and a red colored complex was formed. The absorbance of thecomplex was measured at 510 nm by spectrophotometer.Different experimental parametersaffecting the complexation reactions were studied and optimized. Beer’s law was obeyed in theconcentration range 0.4-10 μgmL-1with a good correlation of 0.992. The limit of detection andlimit of quantification were found to be 0.065 μgmL-1and 0.218 μgmL-1,respectively. The methodhave good reproducibility with a relative standard deviation of 6.26 % (n = 6). The method wassuccessfully applied for the determination of cephalexin in bulk powder and commercialformulation. Percent recoveries were found to range from 95.47 to 103.87 % for the pure form and98.62to 103.35 % for commercial formulations