First- and Second-Order Derivative Spectrophotometry for Individual and Simultaneous Determination of amoxicillin and cephalexin

Abstract

A new spectrophotometric method for individual and simultaneous
determination of amoxicillin and cephalexin depending on the first and second
derivative mode techniques. The first and second derivative spectra of these compounds
permitted individual and simultaneous determination of amoxicillin and cephalexin in
concentration interval of (10 – 60μg.ml-1) by measuring the amplitude of peak-to-base
line, zero cross at certain wavelengths and the area under peak at selected spectrum
intervals. The methods showed reasonable precisionand accuracy and have been applied
to determine amoxicillin and cephalexin in four different pharmaceutical preparations.