Concentration-time courses of pefloxacin in plasma and milk of lactating she-camels (Camelus dromedarius)

Using the microbial inhibition test, the single-dose pharmacokinetics of pefloxacin mesylate dehydrate were studied in six clinically normal lactating she-camels (Camelus dromedarius) after intravenous (IV) and intramuscular (IM) administration of 10 mg/kg body weight (bwt). Blood and milk samples were collected intermittently for a 48 h period, and the pharmacokinetic variables were calculated using compartmental and non-compartmental analytical methods. The plasma course of pefloxacin was best resolved to a two-compartment open model after IV administration and a two-compartment open model with first-order absorption after IM administration. Pefloxacin exhibits a long elimination-phase disposition half-life (t(1/2 beta)) of 4.89 +/- 1.12 h after IV injection and 5.73 +/- 1.42 h after IM administration. The mean volume of distribution at steady state (Vdss) and total body clearance (Cl-tot) values after IV dosing were 1.18 +/- 0.45 l/kg and 0.21 +/- 0.10 l/kg/h, respectively. The observed peak plasma level (C-max) of 3.6 0.1 +/- mu g/ml was rapidly attained at 0.75 h (the time of maximum concentration T-max) after IM administration. The areas under the concentration versus time curves (AUCs) were 44.18 +/- 9.68 mu g.h/ml and 29.42 +/- 6.49 mu g. h/ml after IV and IM administration, respectively. The absolute bioavailability (F%) obtained after IM administration was 71.59 +/- 2.45%. Milk was penetrated quickly, with a mean peak level of 3.24 +/- 0.17 mu g/ml occurring at 1.0 h. The elimination half-life was significantly shorter after IV versus IM administration (4.21 +/- 0.84 h versus 5.32 +/- 0.67 h, respectively). Ultimately, pefloxacin could be useful for treatment of udder infections in she-camels after specific assessment of susceptible microorganisms.