[Pharmacokinetics of cephalexin from two oral formulations in dogs]

Six beagle dogs were treated with cephalexin-monohydrate from 2 oral formulations (Rilexine tablets and Cefaseptin dragees, respectively) in a dosage of 25 mg/kg and plasma concentrations of cephalexin were measured over 8 hours. After solid phase extraction of the samples, cephalexin was determined by high pressure liquid chromatography with UV detection. After administration, Cephalexin was absorbed rapidly and mean maximum plasma concentrations of 30.9 and 27.9 micrograms/ml, respectively, were acquired after approximately 1.6 hours. Minimal inhibitory concentrations of < or = 6.25 micrograms/ml for in vitro sensitive bacteria were maintained for about 5 hours. Cephalexin from the tested preparations reached a mean area under the plasma concentration-time curve of 115.3 and 102.4 micrograms.h/ml, respectively. The plasma concentration decreased rapidly with a mean half life period of 1.4 hours in average. The other calculated pharmacokinetic parameters were also in the area of the data for dogs stated in the literature. There was no clear difference in the pharmacokinetics of both products, especially the bioavailability. Furthermore, both formulations were well tolerated clinically.