Bioavailability and pharmacokinetics of florfenicol in healthy sheep*

Abstract

A study on bioavailability and pharmacokinetics of florfenicol was conducted in 20 crossbred healthy sheep following a single intravenous (i.v.) and intramuscular (i.m.) doses of 20 and 30 mg/kg body weight (b.w.). Florfenicol concentrations in serum were determined by a validated high-performance liquid chromatography method with UV detection at a wavelength of 223 nm in which serum samples were spiked with chloramphenicol as internal standard. Serum concentration-time data after i.v. administration were best described by a three-compartment open model with values for the distribution half-lives (T(1/2alpha)) 1.51 +/- 0.06 and 1.59 +/- 0.10 h, elimination half-lives (T(1/2beta)) 18.83 +/- 6.76 and 18.71 +/- 1.85 h, total body clearance (Cl(B)) 0.26 +/- 0.03 and 0.25 +/- 0.01 L/kg/h, volume of distribution at steady-state (V(d(ss))) 1.86 +/- 0.11 and 1.71 +/- 0.20 L/kg, area under curve (AUC) 76.31 +/- 9.17 and 119.21 +/- 2.05 microg.h/mL after i.v. injections of 20 and 30 mg/kg b.w. respectively. Serum concentration-time data after i.m. administration were adequately described by a one-compartment open model. The pharmacokinetic parameters were distribution half-lives (T(1/2k(a) )) 0.27 +/- 0.03 and 0.25 +/- 0.09 h, elimination half-lives (T(1/2k(e) )) 10.34 +/- 1.11 and 9.57 +/- 2.84 h, maximum concentrations (C(max)) 4.13 +/- 0.29 and 7.04 +/- 1.61 microg/mL, area under curve (AUC) 67.95 +/- 9.61 and 101.95 +/- 8.92 microg.h/mL, bioavailability (F) 89.04% and 85.52% after i.m. injections of 20 and 30 mg/kg b.w. respectively.

Pharmacokinetics of florfenicol following intravenous and intramuscular administration in dogs

“…These results are in agreement with the findings of previous studies on florfenicol performed in sheep (Ali et al 2003;Lane et al 2004), goats (Atef et al 2001;Ali et al 2003), calves (Varma et al 1986;Adams et al 1987;Decraene et al 1997) and broiler chickens (Shen et al 2003). However, Lobell et al (1994), Soback et al (1995) and Jianzhong et al (2004) found that the disappearance of florfenicol from the plasma after i.v. administration was described adequately by a three compartment term.…”

“…The value of AUC (59.44 l/kg/h) after i.v. administration of florfenicol in our study was similar to that recorded in sheep (Jianzhong et al 2004), camels (Ali et al 2003), and higher than goats (Atef et al 2001), chickens (Shen et al 2003), rabbits (Park et al 2007) and dogs (Kim et al 2011), which showed that florfenicol was distributed rapidly in dogs.…”

“…injection of florfenicol, a maximum plasma concentration (C max ) of 3.05 µg/ml was attained post administration. The t max value (1.5 h) was consistent with values recorded in goats (Atef et al 2001), sheep (Jianzhong et al 2004), and camels (Ali et al 2003).…”

“…The V dss was similar to the 1.20 l/kg reported in pigs (Liu et al 2003), 1.45 l/kg in dogs (Park et al 2008) and 1.51 l/kg in chickens (Shen et al 2002). However, this value differs from those reported in sheep (V dss = 0.50 l/kg, Lane et al 2004; V dss = 1.71 l/kg, Jianzhong et al 2004) and goats (V dss = 1.69 l/kg, Atef et al 2001; V dss = 0.69 l/kg, Ali et al 2003). In the present study, florfenicol was more widely distributed than what has been reported for thiamphenicol in dogs (0.66 l/kg; Castells et al 1998).…”

“…The pharmacokinetics of florfenicol have been extensively investigated in veal calves (Varma et al 1986;Adams et al 1987), cows (Bretzlaff et al 1987;Soback et al 1995), horses (McKellar and Varma 1996), goats (Atef et al 2001), broiler chickens (Shen et al 2002), pigs (Liu et al 2003), camels (Ali et al 2003) North American elk (Alcorn et al 2004), sheep (Lane et al 2004;Jianzhong et al 2004), catfish (Park et al 2006) and rabbits (Park et al 2007). However, florfenicol pharmacokinetics in dogs have scarcely been documented (Park et al 2008, Kim et al2011.…”