Ampicillin trihydrate in foals: serum concentrations and clearance after a single oral dose.

This study explores how a single oral dose of ampicillin trihydrate is processed in foals of two different age groups, measuring the concentration and clearance of the drug from serum over a 24-hour period.

Study Methodology and Participants

• The research involved five foals aged between two and three days old.
• Each foal was administered a single oral dose of ampicillin trihydrate. The dose was calculated relative to their bodyweight (20 mg/kg).
• The concentration of ampicillin in serum was then measured at regular intervals over the next 24 hours.

Testing in Different Age Groups

• The entire experiment was repeated with the same foals when they were between 16 and 21 days old.
• This age range was chosen to observe any changes in drug processing as the foals matured.

Results and Findings

• Following the administration of ampicillin, the foals achieved a mean peak serum ampicillin concentration of 5.0 micrograms/ml one hour after treatment when they were two to three days old.
• In the 16 to 21 days old group, the mean peak serum ampicillin concentration was lower—2.7 micrograms/ml—which was reached two hours after the treatment.

Drug Clearance

• The concentration of ampicillin in serum gradually declined post administration in both age groups.
• By the end of the 24-hour observation period, ampicillin was not detected in the serum of any of the foals.
• On average, ampicillin was cleared from the serum at a rate of 17.7 ml/min/kg in the younger group and 35.8 ml/min/kg for the older group.

This study suggests that age may play a significant role in how quickly foals process ampicillin, showing an increased clearance rate in older foals. This could have important implications for dosage and treatment plans involving the use of this antibiotic in veterinary care.