[Cephalosporin pharmacokinetics in rabbits]

The kinetics of the blood serum and urine levels of cephalotin, cephaloridine, cephazolin, cephacetrile, cephapirin, cefalexin and cefradin was studied on rabbits treated with the antibiotics administered intravenously. The pharmacokinetic constants of the cephalosporins were calculated on the basis of the one-compartmental mathematical model. It was shown that cephalotin and cephapirin had the highest blood elimination rates. These antibiotics had higher constants of the elimination rate and lower time values of a two-fold decrease in the blood level. The elimination rates of the other cephalosporins were almost the same. The drugs did not differ in renal clearance. Cephapirin, cephalotin and cephacetrile had the lowest values of excretion with the urine. It was found that the tubular secretion took part in the renal excretion of all cephalosporins. Its proportion was especially high in renal excretion of cephalotin, cephapirin, cephazolin. The value of the "apparent" distribution was much higher for cephalotin, cephacetrile, cefradin and cephapirin as compared to the other drugs. The highest values of the total clearance were observed with respect to cephalotin, cephacetrile and cephapirin, as well as higher values of the extrarenal clearance.