SINGLE-DOSE PHARMACOKINETICS OF CEFAZOLIN IN BOVINE SYNOVIAL-FLUID AFTER INTRAVENOUS REGIONAL INJECTION

The pharmacokinetic properties of cefazolin in the synovial fluid of t he tibiotarsal joint were determined in 10 healthy mature cattle after intravenous regional injection of 250 mg cefazolin. A pneumatic tourn iquet was positioned proximal to the tibiotarsal joint and the intrave nous injection was performed distal to the tourniquet. Synovial fluid concentrations of cefazolin increased in the first 3 0 min and fluctua ted between 54.7 +/- 11.0 mug/ml (mean +/- SEM) and 73.2 +/- 13.2 mug/ ml in the following 90 min while the tourniquet remained inflated. Aft er tourniquet removal, synovial fluid concentration-time curves follow ed first-order one-compartment model decay in most of the animals with an elimination half-life of 0.82 h (harmonic mean). Therapeutic conce ntrations of cefazolin in the synovial fluid of normal joints were rea ched and this injection technique could be used as an alternative to s ystemic administration of antibiotics to provide adequate concentratio ns in a localized area.