title: Pharmacokinetics of lidocaine in serum and milk of mature Holstein cows.
abstract: The purpose of this study was to evaluate the pharmacokinetics of lidocaine in mature Holstein cows following an inverted L and caudal epidural nerve block. Plasma and milk concentrations were determined using high-performance liquid chromatography assay. Pharmacokinetic parameters were estimated using a noncompartmental method. Following administration via inverted L nerve block, serum T(max) was 0.521 +/- 0.226 h and serum C(max) was 572 +/- 207 ng/mL. Serum AUC was 1348 +/- 335 ng.h/mL. Apparent serum t((1/2)beta) was 4.19 +/- 1.69 h and MRT was 5.13 +/- 2.33 h with clearance uncorrected for the extent of absorption of 2.75 +/- 0.68 L/kg/h. The last measurable time of lidocaine detection in serum was 8.5 +/- 1.4 h with a mean concentration of 51 +/- 30 ng/mL. Milk T(max) was detected at 1.75 +/- 0.46 h with C(max) of 300 +/- 139 ng/mL. Milk AUC till the last time was 1869 +/- 450 ng.h/mL with the mean AUC milk to AUC serum ratio of 1.439 +/- 0.374. The last measurable time of lidocaine detection in milk was 32.5 +/- 16.2 h with a mean concentration of 46 +/- 30 ng/mL. There was no detectable lidocaine concentration in any samples following caudal epidural administration.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, 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: S H
authors.initials: SH
authors.lastname: Duran
authors.forename: M D
authors.initials: MD
authors.lastname: Givens
mesh_terms: D015360:Analgesia, Epidural / Q000662:veterinary; D000779:Anesthetics, Local / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D002417:Cattle / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005260:Female; D008012:Lidocaine / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D008892:Milk / Q000737:chemistry*
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine