Abstract
Binding constant, K, for 19 sulfonamides with bovine serum albumin was evaluated spectrophotometrically utilizing the competition between 2-(4'-hydroxyphenylazo)-benzoic acid and sulfonamides. The values of log K well correlated with degree of the decrease in in vitro bacteriostatic activities by the addition of bovine serum. A linear relationship was also observed between log K and pKa for the sulfonamides. The relationships between log K and in vitro bacteriostatic activities against Escherichia coli 0-55 and Staphylococcus aureus 209P were expressed with parabolic curves, which indicated the optimum values of log K being 3.5-4.5 for the potent sulfonamides.
