Comparative analysis of enrofloxa Cin pharma Cokineti Cs in dogs and C ats

The pharmacokinetics of enrofloxacin in dogs and cats after single intravenous (i.v.) and subcutaneous (s.c.) application of 5 mg.kg-1 enrofloxacin hydrochloride was studied and analyzed. Six dogs and six cats, equal number of both genders, were used. Blood samples were collected immediately after enrofloxacin injection and at post injection hours 0.08, 0.33, 0.66, 1, 2, 4, 6, 8, 10, 12 and 24 h. Serum concentrations of the quinolone and its active metabolite were assayed on a high-performance liquid chromatograph. The pharmacokinetic parameters were calculated with specialized pharmacokinetic software (TopFit, v.2.0.). The statistical analysis (Statistica, v.6.0.) performed both parametric and non-parametric analyses − one way ANOVA and Mann-Whitney U test. There were statistically significant differences in serum concentrations and the pharmacokinetics of the drug in both studied animal species. After i.v. application in both species, serum concentrations-time curves fitted the two-compartmental pharmacokinetic model, whereas after s.c. − the one-compartmental model. The studied pharmacokinetic parameters differed statistically significantly between dogs and cats for both routes of administration and were characterized by higher biological half-life and mean residence time, higher volume of distribution, higher AUC0→∞, Cmax and Тmax values, and lower absolute bioavailability of enrofloxacin in cats.