| Abstract: | Interaction of 7 semisynthetic antibiotics (cephaloridine, cephalexin, cephradine, cephazolin, cephalotin, cephacetrile and cephapirin) with proteins of human, bovine and rabbit blood serum, as well as organ and tissue homogenates of rats was studied comparatively. The study showed that binding of the cephalosporins by the blood serum depended on both the chemical structure of the antibiotic and the species affiliation of the protein substrate. The binding lvels of cephazolin and cephalotin by the blood serum proteins (except bovine serum) were the highest, while the binding level of cephaloridine was the lowest. A significant decrease in the values of binding by the serum proteins of the drugs with high percentage of binding was observed when the drug concentrations in solution were increased. Binding of the cephalosporins by the blood serum proteins was in most cases completely reversible. The activity of the cephalosporins decreased in the presence of the rat organ and tissue homogenates. The levels of the activity decrease as compared to the theoretical ones were the highest with the use of cephalotin, cephacetrile and cephapirin. The lowest values of detection of these antibiotics were noted on their incubation with the liver, kidneys and lungs. |
