Pharmacokinetics of a Florfenicol-Tylosin Combination after Intravenous and Intramuscular Administration to Beagle Dogs

Abstract

ABSTRACT. A pharmacokinetic study of a commercial florfenicol-tylosin (2:1) combination product was conducted in six beagle dogs after intravenous (IV) and intramuscular (IM) administration at doses of 10 mg/kg (florfenicol) and 5 mg/kg (tylosin). Serum drug concentrations were determined by a validated high performance liquid chromatography (HPLC) using UV detection. A rapid and nearly complete absorption of both drugs with a mean IM bioavailability of 103.9% (florfenicol) and 92.6% (tylosin), prolonged elimination halflife, and high tissue penetration with steady state volume of distribution of 2.63 l/kg (florfenicol) and 1.98 l/kg (tylosin) were observed. Additional studies, including pharmacodynamic and toxicological evaluation are required before recommendations can be made regarding the clinical application of the product in dogs.

Pharmacokinetic parameters and optimal dosage of a florfenicol and tylosin mixture in beagle dogs

“…The variation in the pharmacokinetic parameters of florfenicol observed in this study might be due to differences in the dose and in the methods used for pharmacokinetic analysis. The volume of distribution and prolonged terminal half-lives of tylosin found after administration of the mixture were comparable to our previous findings in beagle dogs (Kim et al 2011). In contrast, other studies have shown that serum concentrations of tylosin fell rapidly after i.m.…”

“…administration of the FTD mixture was lower than that reported in previous studies following high-dose injection of the mixture in beagle dogs (Kim et al 2011) and after administration of florfenicol alone to dogs and other species of animals (Ali et al 2003;Jiang et al 2006;Park et al 2008). Similarly, the average volume of distribution of florfenicol was slightly lower than our previous value of 2.6 l/kg, which was obtained after administering a high-dose FTD mixture to the same animal species.…”

“…and i.m. injections of the mixture were slightly shorter as compared with the findings following administration of high doses of a similar preparation (Kim et al 2011). However, it was significantly longer compared to the 1.1-hour elimination half- .…”

“…Serum samples were analysed with a Hewlett Packard 1100 HPLC System using HP octadecyl silica columns (200 × 4.6 mm; particle size, 5 µm), a HPLC pump, an auto-injector and a UV lamp system. The HPLC methods, including the mobile phase, flow rate and detection wavelength were determined based on a previously established and validated method (Kim et al 2011).…”

“…and intravenous (i.v.) administration of a mixture at a dose of 10-20 mg/kg of florfenicol and 5-10 mg/kg of tylosin were investigated in dogs (Kim et al 2011) and pigs . However, the pharmacokinetic parameters and optimal doses of florfenicol and tylosin following administration of the mixture at 5 mg/kg of florfenicol and 2.5 mg/kg of tylosin, the most frequently used dose combination, have not been fully documented in dogs.…”