Pharmacokinetics, plasma protein binding and bioavailability of moxifloxacin in Muscovy ducks after different routes of administration

Abstract

In this study the disposition kinetics and plasma availability of moxifloxacin in Muscovy ducks after single intravenous (i.v.), intramuscular (i.m.) and oral (p.o.) administrations of 5 mg kg(-1) b.wt. were investigated. The concentrations of moxifloxacin in the plasma were measured using high-performance liquid chromatography (HPLC) with fluorescence detection on samples collected at frequent intervals after drug administration. Following intravenous injection, the decline in plasma drug concentration was bi-exponential with half-lives of (t(1/2)(alpha)) 0.22+/-0.10h and (t(1/2)(beta)) 2.49+/-0.26h for distribution and elimination phases, respectively. The volume of distribution at steady-state (V(dss)) was 1.02+/-0.14 l kg(-1) and the total body clearance (Cl(tot)) was 0.32+/-0.11 l kg(-1)h(-1), respectively. After intramuscular and oral administration of moxifloxacin at the same dose the peak plasma concentrations (C(max)) were 2.38+/-0.43 and 2.11+/-0.36 microg ml(-1) and were obtained at 1.47+/-0.26 and 1.83+/-0.16h (T(max)), respectively, the elimination half-lives (T(1/2el)) were 3.14+/-0.42 and 2.63+/-0.44h, respectively, and AUC(0-24) were 15.87+/-2.35 and 14.52+/-2.37 microg ml(-1)h(-1), respectively. The systemic bioavailabilities were 96.36+/-11.54% and 86.79+/-12.64%, respectively. In vitro plasma protein binding percent was 32%. We concluded that moxifloxacin might be clinically interesting alternative for the treatment of most sensitive bacterial infections in Muscovy ducks.