title: Blood and tissue concentrations of trimethoprim following its administration alone and in combination with josamycin.
abstract: Following a single oral dose of trimethoprim (10 mg/kg b. wt.) in normal fowls, the highest serum concentration achieved 4 hours post-administration with value of 0.64 microgram/ml. The absorption half-life time was 0.64 hours. The elimination half life was 4.73 hours. During repeated oral administration of 10 mg/kg b. wt., once daily for five consecutive days, trimethoprim peaked in serum, 4 h after each dose. Trimethoprim persisted in all fowl's tissues for 96 hours after stopping of drug administration. After oral administration of josamycin (18 mg/kg b. wt.) and trimethoprim (10 mg/kg b. wt.) in normal fowls, a maximum serum concentration of trimethoprim was recorded at 2 hours with half-life of absorption (t0.5(ab)) valued 0.74 hour. The elimination half-life (t0.5 beta) was 4.37 hours. During repeated oral administration of josamycin (18 mg/kg b. wt.) and trimethoprim (10 mg/kg b. wt.) once daily for five consecutive days in normal fowls, the highest plasma concentrations of trimethoprim occurred 2 hours post each dose. The daily maximum plasma concentrations during the repeated oral administration of both tested drugs were nearly constant.
authors.affiliation: Department of Pharmacology, Faculty of Veterinary Medicine, Zagazig University, Benha, Egypt.
authors.forename: M G
authors.initials: MG
authors.lastname: el-Sayed
authors.forename: M I
authors.initials: MI
authors.lastname: Abd el-Aziz
authors.forename: A M
authors.initials: AM
authors.lastname: Abd el-Azem
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004347:Drug Interactions; D007408:Intestinal Absorption; D015570:Josamycin / Q000494:pharmacology*; D014018:Tissue Distribution; D014295:Trimethoprim / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D014295:Trimethoprim; D015570:Josamycin