Protein Binding Chemistry of Amlodipine Besylate and Olmesartan Medoxomil to Bovine Serum Albumin and their Mutual Effect to Displace each other from the Binding Site: In-Vitro Study

Abstract

The aim of the present study was to evaluate how clinically two important drugs, amlodipine besylate (AB) and olmesartan medoxomil (OM), bind with serum albumin protein and the effect of drug-protein binding when they administrated concomitantly. In this study the binding chemistry of amlodipine and olmesartan to bovine serum albumin (BSA) was evaluated by equilibrium dialysis method utilizing warfarin sodium (Site-I specific probe) and diazepam (Site II specific probe). Association constant and number of binding sites of the experimental drugs were carried out at pH value 7.4 and the temperature at 37°C. The nonlinear curve of the plot suggests the presence of at least two classes of binding site (low affinity binding site and high affinity binding site) of experimental drugs to BSA. In both cases the value of association constants of experimental drugs were found high at pH 7.4. One of the experimental drug (AB) found to bind Site-I and the other drug (OM) found to bind Site II preferentially. During concurrent administration of AB and OM in presence or absence of diazepam, no significant amount of drug is displaced either amlodipine or olmesartan from the binding site on BSA. Also the ability of experimental drugs to displace each other is found less significant in presence of diazepam. As both drugs do not compete for the same binding site, concurrent administration of these drugs can be the effective in the management of cardiovascular problems.