Effect of simultaneous administration of drugs on absorption and excretion. VII. Effect of protein binding on antibacterial activities of sulfonamides in vitro (author's transl)

Abstract

The effect of bovine serum albumin (BSA), human serum albumin (HSA), and bovine serum globulins on the antibacterial activities of sulfonamides was studied by a diffusion method. The antibacterial activities of sulfonamides decreased by the addition of BSA or HSA. A significant correlation was observed between the antibacterial activities of sulfonamides in the presence of BSA and the binding of sulfonamides to BSA. The antibacterial activities of sulfonamides in the presence of HSA were approximately similar to those of BSA. It was also found that the decreasing effect of bovine serum globulins on the antibacterial activity of sulfadimethoxine is much smaller than that of BSA. This finding suggests that the protein most mainly involved in the drug-protein interaction is albumin. In addition, it was found that the displacement of sulfadimethoxine by other. drugs from the protein binding sites affects the antibacterial activity of sulfadimethoxine in the presence of BSA.