spectrophotometric determination of amoxicillin in pharmaceuticals using alizarin red sulphonate in aqueous solution

ABSTRACT A simple, rapid and sensitive spectrophotometric method for the determination of amoxicillin was developed. The method is based on the proton transfer reaction with alizarin red sulphonate in aqueous neutral solution to form aviolet product showing a maximum absorbance at 530 nm with amolar absorptivity of 8090 l.mol-1.cm-1. Beers law is obeyed over the concentration range (1-20) g.ml-1 with the accuracy (average recovery) 100.52% and the precision (RSD) less than 2%. The method was successfully applied for the determination of amoxicillin in pharmaceutical formulation as injection and the results were in good agreement with the standard addition procedure.