PHARMACOKINETICS OF CEFONICID IN LACTATING GOATS AFTER INTRAVENOUS, INTRAMUSCULAR AND SUBCUTANEOUS ADMINISTRATION, AND AFTER A LONG-ACTING FORMULATION FOR SUBCUTANEOUS ADMINISTRATION

Abstract

The single-dose disposition kinetics of cefonicid were determined in clinically normal lactating goats (n=6) after intravenous (IV), intramuscular (IM) and subcutaneous (SC) administration of a conventional formulation, and after subcutaneous administration of a long-acting formulation (SC-LA). Cefonicid concentrations were determined by high performance liquid chromatography with ultraviolet detection. The concentration-time data were analyzed by non-compartmental pharmacokinetic methods. Steady-state volume of distribution (Vss) and clearance (Cl) of cefonicid after IV administration were 0.14  0.03 L/kg and 0.51  0.07 L/h·kg, respectively. Following IM, SC and SC-LA administration, cefonicid achieved maximum plasma concentrations of 14.46  0.82, 11.98  1.92 and 17.17  2.45 mg/L at 0.26  0.13, 0.42  0.13 and 0.83  0.20 hours, respectively. The absolute bioavailabilities after IM, SC and SC-LA routes were 75.34  11.28 %, 71.03  19.14 % and 102.84  15.155 %, respectively. After cefonicid analysis from milk samples, no concentrations were found above LOQ at any sampling time. From these data, cefonicid administered at 20 mg/kg each 12 hours after SC-LA could be effective to treat bacterial infections in lactating animals not affected by mastitis problems.