Gentamicin concentrations in synovial fluid and joint tissues during intravenous administration or continuous intra-articular infusion of the tarsocrural joint of clinically normal horses.
OBJECTIVE
To compare gentamicin concentrations achieved in synovial fluid and joint tissues during IV administration and continuous intra-articular (IA) infusion of the tarsocrural joint in horses.


METHODS
18 horses with clinically normal tarsocrural joints.


METHODS
Horses were assigned to 3 groups (6 horses/group) and administered gentamicin (6.6 mg/kg, IV, q 24 h for 4 days; group 1), a continuous IA infusion of gentamicin into the tarsocrural joint (50 mg/h for 73 hours; group 2), or both treatments (group 3). Serum, synovial fluid, and joint tissue samples were collected for measurement of gentamicin at various time points during and 73 hours after initiation of treatment. Gentamicin concentrations were compared by use of a Kruskal-Wallis ANOVA.


RESULTS
At 73 hours, mean +/- SE gentamicin concentrations in synovial fluid, synovial membrane, joint capsule, subchondral bone, and collateral ligament of group 1 horses were 11.5 +/- 1.5 microg/mL, 21.1 +/- 3.0 microg/g, 17.1 +/- 1.4 microg/g, 9.8 +/- 2.0 microg/g, and 5.9 +/- 0.7 microg/g, respectively. Corresponding concentrations in group 2 horses were 458.7 +/- 130.3 microg/mL, 496.8 +/- 126.5 microg/g, 128.5 +/- 74.2 microg/g, 99.4 +/- 47.3 microg/g, and 13.5 +/- 7.6 microg/g, respectively. Gentamicin concentrations in synovial fluid, synovial membrane, and joint capsule of group 1 horses were significantly lower than concentrations in those samples for horses in groups 2 and 3.


CONCLUSIONS
Continuous IA infusion of gentamicin achieves higher drug concentrations in joint tissues of normal tarsocrural joints of horses, compared with concentrations after IV administration.
Lescun
Timothy B
TB
Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47909-1248, USA.
Ward
Michael P
MP
Adams
Stephen B
SB
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D001842:Bone and Bones / Q000737:chemistry; D005839:Gentamicins / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D006262:Health; D006614:Hindlimb; D006736:Horses / Q000378:metabolism*; D007270:Injections, Intra-Articular; D007275:Injections, Intravenous; D017746:Joint Capsule / Q000378:metabolism*; D008022:Ligaments / Q000737:chemistry; D013582:Synovial Fluid / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D005839:Gentamicins