Abstract
Binding constant, Kac, for 11 N4-acetylsulfonamides with bovine serum albumin was evaluated spectrophotometrically utilizing the competion between 2-(4'-hydroxyphenylazo) benzoic acid and N4-acetylsulfonamides at 37°and 5°, and was compared with Kf, binding constant for free sulfonamides with bovine serum albumin. Free energy and entropy changes for the binding were calculated. The correlations of log (Kac/Kf) with the fraction of unchanged sulfonamides excreted in the urine after the administration, and with half-life for elimination of sulfonamides from human blood plasma were indicated to be significant.
