Pharmacokinetics and bioavailability of terbinafine hydrochloride capsules in beagle dogs.

To study the pharmacokinetics and biavailibility of terbinafine hydrochloride capsules in beagle dogs,a single intravenous(i.v.) and oral(p.o.) administration of terbinafine at a dosage of 10 mg·kg-1 was performed in eight healthy beagles according to a two-period crossover design.Plasma concentrations of terbinafine were determined by a reverse phase high performance liquid chromatographic method.The pharmacokinetic parameters were calculated by noncompartmental analysis with WinNonlin 5.2.1 software.After intravenous administration,the main pharmacokinetic parameters were as follows: AUC0-∞=(5.47±1.03) μg·mL-1·h,Vss=(2.55±0.89) L·kg-1,CL =(1.88±0.33) L·h-1·kg-1,t1/2 =(3.02±1.70) h;whereas after oral dosing,the main pharmacokinetic parameters were as follows: tmax=(1.09±0.37) h,Cmax=(0.39±0.04)μg·mL-1,AUC0-∞ =(0.67±0.18) μg·mL-1·h,Vd/F =(35.17±6.58) L·kg-1,t1/2=(1.69±0.74) h.The absolute bioavailibilty(F) of terbinafine hydrochloride capsules after oral administrtion was(12.54±3.43)%.Terbinafine was absorbed and eliminated rapidly in beagles and the absolute bioavailability was very low.