Gentamicin concentrations in synovial fluid and joint tissues during intravenous administration or continuous intra-articular infusion of the tarsocrural joint of clinically normal horses.

This research study analyzes the differences in gentamicin concentrations present in the synovial fluid and joint tissues in horses when the drug is given through intravenous (IV) administration and intra-articular (IA) infusion. The study concludes that a continuous IA infusion into the tarsocrural joint of a horse results in higher drug concentrations in the joint tissues compared to an IV administration.

Methodology

• The study involved 18 clinically normal horses with a normal tarsocrural joint. Horses were divided into three groups (6 per group) and received gentamicin treatments as per their group type.
• Group 1 received gentamicin through IV (6.6 mg/kg every 24 hours for 4 days), group 2 with a continuous IA infusion of gentamicin into the tarsocrural joint (50 mg/h for 73 hours), and group 3 received a combination of both treatments.
• Samples of serum, synovial fluid, and joint tissue were collected at various time points during the treatment and 73 hours after the initiation of treatment for gentamicin measurement.
• Gentamicin concentrations observed in the three groups were compared using Kruskal-Wallis ANOVA.

Results

• Gentamicin concentrations in the synovial fluid, synovial membrane, joint capsule, subchondral bone, and collateral ligament of horses in group 1 (IV administration) were found to be 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.
• In contrast, the gentamicin concentrations in group 2 horses (IA infusion) were significantly higher with 458.7 +/- 130.3 microg/mL in synovial fluid, 496.8 +/- 126.5 microg/g in the synovial membrane, 128.5 +/- 74.2 microg/g in the joint capsule, 99.4 +/- 47.3 microg/g in the subchondral bone, and 13.5 +/- 7.6 microg/g in the collateral ligament.
• It was observed that gentamicin concentrations in the synovial fluid, synovial membrane, and joint capsule of horses in group 1 were significantly lower than concentrations in the samples for horses in groups 2 and 3.

Conclusions

• This research concludes that a continuous intra-articular (IA) infusion of the drug gentamicin leads to higher concentrations of the drug in joint tissues of horses, when compared to intravenous (IV) administration.
• This finding could lead to improvements in treatment strategies for joint diseases in horses, providing a more effective method to concentrate medication within the affected area.