title: Pharmacokinetics of ketamine in plasma and milk of mature Holstein cows.
abstract: The purpose of this study was to evaluate the pharmacokinetics of ketamine in mature Holstein cows following administration of a single intravenous (i.v.) dose. Plasma and milk concentrations were determined using a high-performance liquid chromatography assay. Pharmacokinetic parameters were estimated using a noncompartmental method. Following i.v. administration, plasma T(max) was 0.083 h and plasma C(max) was 18,135 ± 22,720 ng/mL. Plasma AUC was 4484 ± 1,398 ng·h/mL. Plasma t(½β) was 1.80 ± 0.50 h and mean residence time was 0.794 ± 0.318 h with total body clearance of 1.29 ± 0.70 L/h/kg. The mean plasma steady-state volume of distribution was calculated as 0.990 ± 0.530 L/kg and volume of distribution based on area was calculated as 3.23 ± 1.51 L/kg. The last measurable time for ketamine detection in plasma was 8.0 h with a mean concentration of 24.9 ± 11.8 ng/mL. Milk T(max) was detected at 0.67 ± 0.26 h with C(max) of 2495 ± 904 ng/mL. Milk AUC till the last time was 6593 ± 2617 ng·h/mL with mean AUC milk to AUC plasma ratio of 1.99 ± 2.15. The last measurable time that ketamine was detected in milk was 44 ± 10.0 h with a mean concentration of 16.0 ± 9.0 ng/mL.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA. sellegl@auburn.edu
authors.forename: G
authors.initials: G
authors.lastname: Sellers
authors.forename: H C
authors.initials: HC
authors.lastname: Lin
authors.forename: M G
authors.initials: MG
authors.lastname: Riddell
authors.forename: W R
authors.initials: WR
authors.lastname: Ravis
authors.forename: Y J
authors.initials: YJ
authors.lastname: Lin
authors.forename: S H
authors.initials: SH
authors.lastname: Duran
authors.forename: M D
authors.initials: MD
authors.lastname: Givens
mesh_terms: D000700:Analgesics / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics*; D000818:Animals; D019540:Area Under Curve; D002417:Cattle / Q000097:blood*; D005260:Female; D006207:Half-Life; D007649:Ketamine / Q000008:administration & dosage / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics*; D008892:Milk / Q000737:chemistry*
chemical_list: D000700:Analgesics; D007649:Ketamine