title: Influence of ormetoprim on the bioavailability, distribution, and pharmacokinetics of sulfadimethoxine in rainbow trout (Oncorhynchus mykiss).
abstract: 1. Half lives of distribution and elimination phases of 14C-sulfadimethoxine following i.v. dosing of sulfadimethoxine/ormetoprim (SDM/OMP, 42/8 mg/kg) were 0.4 and 16.1 hr respectively. The apparent volume of distribution was 503.9 ml/kg. 2. In vitro plasma protein binding of 14C-SDM was not altered by increasing concentrations of unlabeled OMP. Similarly, binding of 14C-OMP was not altered by SDM. 3. Peak plasma concentrations of 14C-SDM following oral administration of SDM/OMP were observed at 20 hr with an apparent bioavailability of 38%. 4. Oral dispositional studies revealed the highest concentrations of 14C-SDM in bile, intestine, liver and fat. 5. Parent SDM and N-acetylated SDM were detected in plasma from i.v. and orally dosed animals. 6. The pharmacokinetics and distribution of 14C-SDM were not influenced by OMP co-administration.
authors.affiliation: Department of Veterinary Physiology, Pharmacology and Toxicology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803.
authors.forename: B F
authors.initials: BF
authors.lastname: Droy
authors.forename: T
authors.initials: T
authors.lastname: Tate
authors.forename: J J
authors.initials: JJ
authors.lastname: Lech
authors.forename: K M
authors.initials: KM
authors.lastname: Kleinow
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001682:Biological Availability; D001798:Blood Proteins / Q000378:metabolism; D004338:Drug Combinations; D004347:Drug Interactions; D005260:Female; D008297:Male; D011485:Protein Binding / Q000187:drug effects; D011743:Pyrimidines / Q000494:pharmacology*; D012487:Salmonidae / Q000378:metabolism*; D012588:Scintillation Counting; D013412:Sulfadimethoxine / Q000493:pharmacokinetics*; D014018:Tissue Distribution / Q000187:drug effects; D014337:Trout / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D001798:Blood Proteins; D004338:Drug Combinations; D011743:Pyrimidines; D013412:Sulfadimethoxine; C100125:ormetoprim