Studies of In-Vitro Amlodipine and Arsenic Displacement Interaction at Binding Sites of Bovine Serum Albumin

In this study, the binding of amlodipine (a Ca ++ channel Blocker) and arsenic (metalloid) to bovine serum albumin (BSA) was studied by equilibrium dialysis(ED) method in order to have an insight into their binding chemistry to BSA. Free amlodipine concentration was increased due to addition of arsenic which reduced the binding of the compounds to BSA. However, the free fraction was not increased to a level as it was expected from direct competitive displacement. The free amlodipine concentration was increased according to increasing the amlodipine concentration when only the BSA was present. When the binding sites were blocked by sufficient amount of arsenic, the increment of free concentration of amlodipine was prominent. When no arsenic was added, the free concentration of amlodipine was only 6.6% to 10.3%; whereas this release was 7.65% to 13.65% when arsenic was added with an increasing concentration from 1x10 -5 M to 12x10 -5 M. This suggests that in the presence of arsenic, the amlodipine is slowly displaced from its high affinity binding site with increasing arsenic concentration, the increment was small as compared to that of amlodipine to BSA.