Gentamicin sulfate in the horse: serum, synovial, peritoneal, and urine concentrations after single dose intramuscular administration.

The research investigates the concentration levels of gentamicin sulfate, a type of antibiotic, in horses, specifically in their serum, synovial fluid, peritoneal fluid, and urine after a single dose is given intramuscularly.

Study Design and Implementation

• The study comprised of ten healthy adult mares, which were given a single dose of gentamicin sulfate intramusically. The dosage rate was 2.2 mg/kg for each horse.
• Over 48 hours after the drug administration, the researchers measured gentamicin concentration in serum, synovial fluid, peritoneal fluid and urine.

Results and Findings

• The researchers found that the peak concentration of gentamicin sulfate was reached in the serum one hour after the drug was administered, with a mean value of 5.73 micrograms/ml.
• The gentamicin concentrations in the synovial and peritoneal fluids also peaked two hours after drug administration, with mean values of 2.41 and 3.92 micrograms/ml respectively. After peaking, these concentrations dropped in line with the serum concentrations and were not detectable at 48 hours.
• The gentamicin concentration in the urine was significantly higher than the other fluids, peaking one hour after administration at 424.9 micrograms/ml.

Implications of Findings

• The research data shows that gentamicin sulfate is rapidly absorbed and dispersed in the horse’s body when administered intramuscularly.
• The high concentration levels in the urine at 1 hour after drug administration indicate that gentamicin is also rapidly excreted from the horse’s system.
• The gentamicin detection in the synovial and peritoneal fluids within 2 hours suggests that the drug can potentially be effective at treating infections in these parts of the horse’s body.
• With the drug being undetectable at 48 hours post administration, this indicates that gentamicin has a relatively short biological half-life in horses and it suggests that regular dosing would be required for prolonged treatment.