Plasma disposition of florfenicol after intramuscular administration in rabbits pretreated with pentoxifylline

This work aimed to assess the effects of the coadministration of pentoxifylline (PTX) on the pharmacokinetic profile of florfenicol (FFC) after intramuscular administration in rabbits. Ten New Zealand white rabbits, 1 year of age and 3.9 +/- 0.1 kg body weight, were assigned according to a randomized block design to Group 1 (FFC): treated with 30 mg/kg of FFC intramuscularly, and Group 2 (PTX + FFC) treated with an oral dose of 30 mg/kg PTX 45 min before the intramuscular injection of 30 mg/kg FFC. Blood samples were collected before and at different times between 0.5 and 12.0 h after drug administration. FFC plasma concentrations were determined by high-performance liquid chromatography. Results showed that IM injection of the long-acting formulation of FFC in rabbits resulted in a slow increase in mean plasma concentrations reaching a C-max of 3.09 +/- 0.52 ug/mL at 2.8 +/- 0.45 h (T-max) after drug administration. While coadministration of PTX and FFC decreased the time to achieve the maximal concentration by modifying the absorption of FFC without changes in the other pharmacokinetic parameters.