USE OF DIFFERENCE SPECTROPHOTOMETRY TO STUDY DRUG-PROTEIN INTERACTIONS .4. BINDING OF PENICILLINS TO HUMAN-SERUM ALBUMIN

Abstract

The compound 2-(4''-hydroxybenzeneazo) benzoic acid is a spectrophotometric probe which shows spectral absorption changes on binding to protein. The absorbance differences measured upon the addition of this probe to a solution of human serum albumin alone and human serum albumin in the presence of selected penicillins were used as an indirect method to determine the binding of these drugs to human serum albumin under the conditions described. Based on the displacement results, it was concluded that penicillins bind to human serum albumin by electrostatic force and through their side-chain and that increased hydrophobicity of the side-chain reinforces the binding.