title: Relative bioavailability of microgranulated sulfadimidine in veal calves.
abstract: The kinetics of free and microgranulated sulfadimidine were compared in milk-fed calves dosed orally (180 mg/kg) in a crossover study. Microgranulation results in delayed absorption of sulfadimidine and poor bioavailability, with the area under the plasma concentration-time curve (AUC(0-infinity)) reduced from 7400 to 3781 micrograms.h/mL, and maximum plasma concentration (Cmax) reduced from 188.1 +/- 39.0 to 84.41 +/- 22.6 micrograms/mL. It is concluded that sulfadimidine microgranulated with long chain fatty acids is not suitable for use in milk-fed calves; the gastrointestinal transit time is too rapid to allow full release of the drug, markedly limiting its bioavailability. In adult animals, or in the young of other animal species in which digesta transit time is slower than in calves, the bioavailability of microgranulated sulfadimidine may be much greater.
authors.affiliation: Department of Public Veterinary Health and Animal Pathology, Faculty of Veterinary Medicine, University of Bologna, Ozzano Emilia (BO), Italy.
authors.forename: P
authors.initials: P
authors.lastname: Anfossi
authors.forename: C
authors.initials: C
authors.lastname: Montesissa
authors.forename: P
authors.initials: P
authors.lastname: Pezzi
authors.forename: A
authors.initials: A
authors.lastname: Formigoni
mesh_terms: D000284:Administration, Oral; D000704:Analysis of Variance; D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D001682:Biological Availability; D002417:Cattle / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D018592:Cross-Over Studies; D004304:Dosage Forms; D004305:Dose-Response Relationship, Drug; D005772:Gastrointestinal Transit / Q000187:drug effects; D013418:Sulfamethazine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D004304:Dosage Forms; D013418:Sulfamethazine