Effect of Mastitis on Pharmacokinetics of Levofloxacin Following Single Dose Intravenous Administration in Goats

Disposition kinetics of levofloxacin was investigated after single dose intravenous administration at the dose of 10 mg/kg in six healthy and six mastitic Black Bengal lactating goats. Mastitis was induced in goats by coagulase positive Staphylococcus aureus . The maximum milk concentration was higher in mastitic goats (17.01 ± 0.67 μg/ ml) as compared to healthy (14.75 ± 0.95 μg/ml). The therapeutic milk concentration in mastitic goats (0.10 ± 0.00 to 16.61 ± 0.70 μg/ml) was maintained for 48 h, which was significantly longer than healthy goats (36 h). The t ½ β in plasma (5.08 ± 0.18 h) and milk (7.28 ± 0.09 h) of mastitic goats were significantly longer than healthy goats (4.04 ± 0.24 and 4.16 ± 0.76 h). The total body clearence in plasma of healthy goats (5.64 ± 0.78 ml/kg/min) was almost similar to mastitic goats (5.82 ± 0.44 ml/kg/min). The AUC milk /AUC plasma ratio (3.36) in mastitic goats indicated extensive penetration of levofloxacin from plasma to milk. The t 1/2 milk /t 1/2 plasma ratio was 1.43. The AUC/MIC ratio in plasma and milk of mastitic goats were 296 and 1014 respectively. Based on the plasma kinetic parameters, it was concluded that levofloxacin may be used for treatment of mastitis in goats.