Disposition kinetics and urinary excretion of ofloxacin following intramuscular administration in buffalo calves

อังกฤษ

Buffaloes;Buffalo calves;Ofloxacin;Pharmacokinetics;Urinary excretion;India

Pharmacokinetics and urinary excretion of ofloxacin were determined in male buffalo calves following single intramuscular administration (5 mg/kg). The disposition of ofloxacin followed a one-compartment open model after the absorption phase following a single i.m. injection. The drug was rapidly the absorbed and at 5 minutes, the concentration was 2.55 micro g/ml. The peak plasma level was 3.78 micro g/ml at 30 minutes, this declined gradually to 0.54 micro g/ml at 360 minutes. The drug remained above the minimum therapeutic concentration (MIC90: 0.5 micro g/ml) for 6 h. The absorption rate constant (ka) was 3.70 1/h with an absorption half life (t1/2ka) of 0.19 h. The observed peak plasma concentration (Cmax) was 3.78 micro g/ml at 30 minutes (tmax). The drug was not detected in plasma after 6 h, as also indicated by a high value of the elimination rate constant (beta: 0.367 1/h) and a short biological half life (t1/2 beta: 1.91 h). The volume of distribution (Vz(area): 0.69 L/kg) revealed moderate to good distribution and tissue penetration of ofloxacin. The total body clearance (ClB) was 0.25 L/kg/h. The area under plasma concentration curve (AUC) was 12.40 micro g/ml.h. About 54 percent of the total administered dose of ofloxacin was excreted in urine in 48 h. An optimal dosage regimen of ofloxacin following a single intramuscular injection in buffalo calves would be 6.5 mg/kg followed by 6 mg/kg at 8 h intervals to maintain a minimum therapeutic concentration of 0.5 micro g/ml suitable for the treatment of systemic infections in buffalo calves.

[1] Sandeep Kumar (CCS Haryana Agricultural University, Hisar Haryana (India). College of Veterinary Sciences, Department of Pharmacology and Toxicology)
[2] Punia, J.S. (CCS Haryana Agricultural University, Hisar Haryana (India). College of Veterinary Sciences, Department of Pharmacology and Toxicology)
[3] Jain, S.K. (CCS Haryana Agricultural University, Hisar Haryana (India). College of Veterinary Sciences, Department of Pharmacology and Toxicology)