title: Plasma and synovial fluid concentrations of gentamicin in horses after intra-articular administration of buffered and unbuffered gentamicin.
abstract: The concentration of gentamicin in plasma and synovial fluid of normal adult horses was measured periodically for 24 hours after IV (2.2 mg/kg of body weight), intra-articular (IA; 150 mg), and simultaneous IV and IA administrations. Gentamicin also was buffered with sodium bicarbonate (3 mEq) and then was administered IA and simultaneously IV and IA. Synovial fluid specimens were obtained via an indwelling catheter placed into the antebrachiocarpal joint. The peak mean plasma gentamicin concentration (8.30 micrograms/ml) after IV administration was significantly (P less than 0.05) greater than that (0.69 microgram/ml) after IA administration of gentamicin and that (0.55 microgram/ml) after administration of gentamicin buffered with sodium bicarbonate. Gentamicin concentration greater than a therapeutic concentration was not attained in the plasma after IA administration of buffered or unbuffered gentamicin. The peak mean synovial fluid concentration (1,828 micrograms/ml) after IA administration of unbuffered gentamicin was significantly (P less than 0.05) greater than that (2.53 micrograms/ml) after IV administration and significantly (P less than 0.05) less than that (5,720 micrograms/ml) after simultaneous IV and IA administration. The peak mean synovial fluid concentration after IA administration of buffered gentamicin, with and without simultaneous IV administration (2,128 and 2,680 micrograms/ml, respectively), was not significantly different than that after IA treatment with unbuffered gentamicin. Mean synovial fluid concentration did not differ significantly between groups after IA administration of gentamicin in any combination at postinjection hours 8, 12, and 24, but remained significantly (P less than 0.05) greater than that at the same times after IV administration.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis 95616.
authors.forename: K C
authors.initials: KC
authors.lastname: Lloyd
authors.forename: S M
authors.initials: SM
authors.lastname: Stover
authors.forename: J R
authors.initials: JR
authors.lastname: Pascoe
authors.forename: J D
authors.initials: JD
authors.lastname: Baggot
authors.forename: C
authors.initials: C
authors.lastname: Kurpershoek
authors.forename: S
authors.initials: S
authors.lastname: Hietala
mesh_terms: D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D002021:Buffers; D002350:Carpus, Animal; D005260:Female; D005839:Gentamicins / Q000008:administration & dosage / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D006736:Horses / Q000378:metabolism*; D007270:Injections, Intra-Articular; D007275:Injections, Intravenous; D008297:Male; D012964:Sodium / Q000494:pharmacology; D017693:Sodium Bicarbonate; D013582:Synovial Fluid / Q000032:analysis*
chemical_list: D001639:Bicarbonates; D002021:Buffers; D005839:Gentamicins; D017693:Sodium Bicarbonate; D012964:Sodium