Serum activity/concentration profiles of a sustained-released formulation of sulphathiazole-trimethoprim (2.5:1) in calves.
Thirty-six two-week-old healthy Holstein-Friesian calves weighing between 52 and 58 kg were divided at random into three groups of 12; group A calves were given a single oral bolus containing 2.5 g sulphathiazole and 1 g trimethoprim in a sustained-release formulation; group B received the same doses of the drugs but the trimethoprim was not in a sustained-release formulation; group C received a bolus containing 2.5 g sulphathiazole and 0.5 g conventional trimethoprim. Blood samples were collected at intervals for two days, the serum was separated and the composite antibacterial activity profiles of the mixture were analysed by an agar-diffusion microbiological method. The mean maximum activities in the serum of the three groups were 23.4 microg/ml in group A, 9.25 microg/ml in group B and 8.01 microg/ml in group C. The mean areas under the curves of the serum activity time curves were 838 microg/ml/hour in group A, 216 microg/ml/hour in group B and 182 microg/ml/hour in group C.
Sumano
H
H
Department of Physiology and Pharmacology, School of Veterinary Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico.
Gutierrez
L
L
Zamora
M A
MA
Perez
M
M
Cruz
C
C
D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D019540:Area Under Curve; D002417:Cattle / Q000378:metabolism*; D003692:Delayed-Action Preparations; D004338:Drug Combinations; D000077589:Sulfathiazole; D013432:Sulfathiazoles / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D014295:Trimethoprim / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics
D000890:Anti-Infective Agents; D003692:Delayed-Action Preparations; D004338:Drug Combinations; D013432:Sulfathiazoles; D014295:Trimethoprim; D000077589:Sulfathiazole