Summary
Six calves with suppurative arthritis were given a single im injection of sodium cephapirin at a dosage of 10 mg/kg of body weight. Cephapirin concentrations were serially measured in serum and in normal and suppurative synovial fluid over a 24-hour period. Mean peak serum concentration was 6.33 μl/ml at 20 minutes after injection. The highest cephapirin concentrations in normal and suppurative synovial fluid were 1.68 and 1.96 μg/ml, respectively, 30 minutes after injection. Overall mean cephapirin concentration in normal synovial fluid for the first 4 hours (1.04 ± 0.612 μg/ml) was not significantly different from that in suppurative synovial fluid (0.88 ± 0.495 μg/ml; P > 0.05). Elimination half-life was 0.60 hours and clearance was 1,593 ml/h/kg.