Disposition of sulfadimethoxine in camels (Camelus dromedarius) following single intravenous and oral doses.
Single-dose pharmacokinetics of sulfadimethoxine were determined in six adult camels (Camelus dromedarius) following administration of a mean dosage of 17.5 +/- 2.7 mg/kg both i.v. and p.o. Serial blood samples were collected through an indwelling jugular catheter intermittently for 5 days for both routes. Sulfadimethoxine was assayed using high-performance liquid chromatography. Serum drug concentration versus time data for each animal was subjected to linear regression, with the best-fit model selected based on residual analysis. The data fit best into a two-compartment open model, with first-order input for oral administration. For orally administered drug, mean maximum serum concentration of 19.3 +/- 1.7 microg/ml was reached at 11.41 +/- 2.59 hr, with an elimination rate constant of 0.09/hr +/- 0.05/hr and an elimination half-life of 11.7 +/- 3 hr. Mean peak serum concentration following i.v. administration was 223 +/- 48 microg/ml. Mean volume of distribution at steady state was 0.393 +/- 0.049 L/kg. Elimination rate constants differed with i.v. and oral administration, suggesting a flip-flop model. Oral bioavailability was 103% +/- 38%. Comparison of maximum serum concentrations to the microbial breakpoint concentration reported for sulfadimethoxine (512 microg/ml) suggests that the dose used in this study, 17.5 +/- 2.7 mg/kg, is insufficient for achieving therapeutic serum levels.
Chatfield
J
J
Veterinary Teaching Hospital, College of Veterinary Medicine, Texas A&M University, College Station, Texas 77843, USA.
Jensen
J
J
Boothe
D
D
Herzog
T
T
Junkins
K
K
D000284:Administration, Oral; D000818:Animals; D000890:Anti-Infective Agents / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D002162:Camelus / Q000097:blood / Q000378:metabolism*; D002408:Catheters, Indwelling / Q000662:veterinary; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D018592:Cross-Over Studies; D005260:Female; D006207:Half-Life; D007275:Injections, Intravenous / Q000662:veterinary; D008657:Metabolic Clearance Rate; D011247:Pregnancy; D013412:Sulfadimethoxine / Q000493:pharmacokinetics*
D000890:Anti-Infective Agents; D013412:Sulfadimethoxine