Disposition kinetics of moxifloxacin in lactating ewes

Plasma and Tissue Disposition of Moxifloxacin in Japanese Quail ( Coturnix japonica )

Plasma disposition and depletion of moxifloxacin were investigated in Japanese quail ( Coturnix japonica ) after single intravenous, intramuscular, and oral administration of 5 mg/kg and after intramuscular and oral administration of 5 mg/kg q24h for 5 consecutive days, respectively. Drug concentrations in plasma and tissues were measured by high-performance liquid chromatography with fluorescence detection. After intravenous injection, plasma drug concentration-time curves were best described by a 2-compartment open model. The decline in plasma drug concentration was biexponential with half-lives of 0.3 hours and 2.18 hours for distribution and elimination phases, respectively. Steady-state volume of distribution and total body clearance after intravenous administration were estimated to be 1.12 L/kg and 0.41 L/h per kilogram, respectively. After intramuscular and oral administration of moxifloxacin at the same dose, the peak plasma concentrations were 2.14 and 1.94 μg/mL and were obtained at 1.4 and 1.87 hours, respectively, and the elimination half-lives were 2.56 and 1.97 hours, respectively. The systemic bioavailabilities were 92.48% and 87.94%, respectively. Tissue levels after intramuscular and oral administration were highest in liver and kidneys, respectively, and decreased in the following order: plasma, lungs, and muscle. Moxifloxacin concentrations after intramuscular and oral administration were below the detection limit of the assay in tissues and plasma after 120 hours.

Disposition Kinetic of Moxifloxacin following Intravenous, Intramuscular, and Subcutaneous Administration in Goats

The present study was carried out to investigate disposition kinetics of moxifloxacin following single-dose intravenous (i.v.), intramuscular (i.m.), and subcutaneous (s.c.) administration at a dose rate of 5 mg/kg of body weight (b.wt.) in goats. Plasma samples collected after treatments were analyzed for drug concentration using high-performance liquid chromatography (HPLC). After i.v. administration, distribution of the drug was rapid and wide as reflected by high steady-state volume of distribution. Drug elimination was relatively faster with a total body clearance of 0.59 ± 0.03 L/h/kg. Following i.m. injection, the drug has shown the rapid and near-to-complete absorption with bioavailability of 98.20 ± 3.96 per cent. The maximum plasma drug concentration (Cmax) of 1.21 ± 0.04 μg/mL was attained at 1 h (Tmax). The drug was widely distributed as reflected by high apparent volume of distribution. The elimination half-life (t 1/2β ) of the drug was 6.26 ± 0.08  h. Following s.c. administration, the drug was rapidly absorbed (Cmax: 1.16 ± 0.02 μg/mL; tmax: 1 h) and slowly eliminated from the body. The elimination half-life and total body clearance (ClB) were 5.61 ± 0.10 h and 0.60 ± 0.03 L/h/kg, respectively. The bioavailability of moxifloxacin following s.c. administration was 90.44 ± 3.96 per cent.

Disposition kinetics of levofloxacin in sheep after intravenous and intramuscular administration

The present study was planned to investigate the disposition kinetics of levofloxacin in plasma of female native Barky breed sheep after single intravenous (IV) and intramuscular (IM) administration of 4 mg/kg body weight. The concentrations of levofloxacin in the plasma were measured using high-performance liquid chromatography (HPLC) with a UV detector on samples collected at 0, 0.08, 0.16, 0.33, 0.5, 1, 2, 4, 6, 8, 10, 12, 18, 24, 32, and 48 h after treatment. Following intravenous injection, the decline in plasma drug concentration was biexponential with half-lives of (t_1/2α) 0.33 ± 0.12 h and (t_1/2β) 3.29 ± 0.23 h for distribution and elimination phases, respectively. The volume of distribution at steady state V_(d(ss)) was 0.86 ± 0.23 l/kg. After intramuscular administration of levofloxacin at the same dose, the peak plasma concentration (C_max) was 3.1 ± 0.35 μg/mL and was obtained at 1.64 ± 0.29 h (T_max), the elimination half-life (T_1/2el) was 3.58 ± 0.30 h, and AUC was 20.24 ± 1.31 μg.h/mL. The systemic bioavailability was 91.35 ± 6.81 %. In vitro plasma protein binding was 23.74%. When approved therapy fails, levofloxacin may be used in some countries for therapy of food animals, however, that is not true in the US.

Pharmacokinetics and intramuscular bioavailability of difloxacin in dromedary camels (Camelus dromedarius)

Single-dose disposition kinetics of difloxacin (5mg/kg bodyweight) were determined in clinically normal male dromedary camels (n=6) following intravenous (IV) and intramuscular (IM) administration. Difloxacin concentrations were determined by high performance liquid chromatography with fluorescence detection. The concentration-time data were analysed by compartmental and non-compartmental kinetic methods. Following a single IV injection, the plasma difloxacin concentration-time curve was best described by a two-compartment open model, with a distribution half-life (t(1/2alpha)) of 0.22+/-0.02h and an elimination half-life (t(1/2beta)) of 2.97+/-0.31h. Steady-state volume of distribution (V(dss)) and total body clearance (Cl(tot)) were 1.02+/-0.21L/kg and 0.24+/-0.07L/kg/h, respectively. Following IM administration, the absorption half-life (t(1)(/)(2ab)) and the mean absorption time (MAT) were 0.44+/-0.03h and 1.53+/-0.22h, respectively. The peak plasma concentration (C(max)) of 2.84+/-0.34microg/mL was achieved at 1.42+/-0.21h. The elimination half-life (t(1/2el)) and the mean residence time (MRT) was 3.46+/-0.42h and 5.61+/-0.23h, respectively. The in vitro plasma protein binding of difloxacin ranged from 28-43% and the absolute bioavailability following IM administration was 93.51+/-11.63%. Difloxacin could be useful for the treatment of bacterial infections in camels that are sensitive to this drug.