Pharmacokinetics of ciprofloxacin after intravenous and intramuscular administration in healthy horses

The pharmacokinetic properties of ciprofloxacin were determined in six horses after single intravenous and intramuscular administration with a dose of 4 mg as ciprofloxacin base per kg of body weight. After intravenous and intramuscular administration, plasma drug concentrations were best fitted to an open two-compartment and one-compartment, respectively. After ciprofloxacin intravenous administration, the mean distribution (T_1/2α) and elimination half-life (T_1/2β) showed 0.41 h and 5.86 h. The mean volume of distributions at steady state (Vd_ss) was 2.05 L/kg. After ciprofloxacin intramuscular administration, the mean maximal absorption concentrations (C_max) were 0.60 μg/ml at 2.22 h (T_max) The mean absorption (T_1/2ka) and elimination half-life (T_1/2ke) showed 0.55 h and 7.19 h. In conclusion, we could suggest that optimal dosage calculated from pharmacokinetic data would be 3.16 mg/kg for intravenous and 3.40 mg/kg for intramuscular administrations every 12 hours.