Abstract
The binding of seven commercial sulfonylureas (tolbutamide, chlorpropamide, acetohexamide, carbutamide, chlorpentazide, azepinamide, and tolazamide) by bovine serum albumin (BSA) was investigated using an equilibrium dialysis procedure. The Scatchard plots of the data of six sulfonylureas except tolazamide indicated the presence of two kinds of binding sites. Assuming both concentrations of BSA and sulfonylureas are 5×10-4M, the results of calculation demonstrated that tolbutamide has large binding percentages (97.2%) and tolazamide is relatively small (88.8%). Although the effect of pH and ionic strength of solvent was investigated, the exact mechanism of binding could not be elucidated. A good correlation was observed between the logarithms of BSA binding constants and octanol-water partition coefficients for sulfonylureas. It seemed that their molecular structure that leads to a higher lipophilicity will result in an enhanced BSA binding.
