Pharmacokinetics and metabolic inertness of doxycycline in young pigs.
The disposition of doxycycline hyclate after IV administration of 20 mg/kg of body weight was studied in 6 pigs. Median elimination half-life, estimated in 4 pigs, was 3.92 hours. Mean (+/- SEM) total body clearance was 1.67 +/- 0.18 ml/min/kg, and mean apparent volume of distribution at steady state was 0.53 +/- 0.04 L/kg. In 2 pigs, secondary peaks in the logarithmic serum concentration-time profile suggested discontinuous enterohepatic cycling, and precluded using these pigs in the pharmacokinetic analysis. The extent of doxycycline binding to serum protein was 93.1 +/- 0.2%. Serum or urine from 3 of the pigs was analyzed by use of photodiode array detection and mass spectrometry of a high-performance liquid chromatographic column effluent. These procedures documented lack of doxycycline biotransformation in pigs. It is concluded that, despite an elimination half-life shorter than that reported in other species, doxycycline may be a valuable antimicrobial drug for use in swine practice, pending the development of appropriate formulations.
Riond
J L
JL
Department of Anatomy, College of Veterinary Medicine, North Carolina State University, Raleigh 27606.
Riviere
J E
JE
D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D004318:Doxycycline / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D006207:Half-Life; D007275:Injections, Intravenous / Q000662:veterinary; D013058:Mass Spectrometry / Q000662:veterinary; D008657:Metabolic Clearance Rate; D013552:Swine / Q000097:blood / Q000378:metabolism* / Q000652:urine; D013997:Time Factors
D004318:Doxycycline