title: Disposition of sulfonamides in food-producing animals IV: Pharmacokinetics of sulfamethazine in cattle following administration of an intravenous dose and three oral dosage forms.
abstract: The plasma and urine data obtained following intravenous administration of sulfamethazine to cattle were fit to a one-compartment pharmacokinetic model with a half-life of elimination of 9 hr and a volume of distribution of 0.35 liter/kg. Sulfamethazine was eliminated by excretion of unchanged sulfamethazine (18%) into urine and by formation of three metabolites subsequently excreted into urine. Sulfamethazine also was administered as a solution, a rapid-release bolus, and a sustained-release bolus. The change in the urinary metabolic pattern with different routes of administration suggested that first-pass metabolism was occurring during the absorption process. The absorption half-life was 6 hr. The absorption process for the two solid boluses kinetically appeared to include a dissolution step.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D002417:Cattle / Q000378:metabolism*; D003692:Delayed-Action Preparations; D005260:Female; D007275:Injections, Intravenous; D007700:Kinetics; D008954:Models, Biological; D012995:Solubility; D012996:Solutions; D013418:Sulfamethazine / Q000008:administration & dosage / Q000378:metabolism*; D013997:Time Factors
chemical_list: D003692:Delayed-Action Preparations; D012996:Solutions; D013418:Sulfamethazine