Pharmacokinetics and applications of ampicillin sodium as an intravenous infusion in the horse.

This research article investigates the pharmacokinetic behavior and practical applications of ampicillin sodium when administered as a continuous intravenous infusion in horses. The specific administration regime was designed to achieve plasma ampicillin concentrations within a targeted range, and the results showed positive correlation with the predicted calculations, indicating the success of their approach.

Study Design and Execution

• The team designed an administration regime purposed to deliver ampicillin sodium continuously through intravenous infusions in horses. The objective of this regime was to sustain plasma ampicillin concentrations within the range of 5 and 10 micrograms/ml for a 4-hour period.
• To rapidly achieve steady-state plasma concentrations, a loading dose of ampicillin sodium was given first. This dose was calculated at 2 mg/kg of the horse’s body weight and was also administered intravenously.
• Following the initial dose, an infusion system was employed to continuously administer ampicillin at an average rate of 19.2 micrograms/min/kg body weight.

Results and Findings

• The team found that the plasma concentrations achieved during the infusion period correlated significantly with the predicted calculations. These predictions were based on specific pharmacokinetic parameters.
• The research found a mean steady-state plasma concentration of about 5.94 micrograms per milliliter. Ampicillin showed an apparent steady-state volume of distribution (Vdss) of 175.43 ml/kg. These values are calculated averages, and some variation was expected and observed, represented by the Standard Error of the Mean (SEM) values provided.
• A decrease in concentration was observed after the pump was disconnected. The researchers noted that the concentrations declined in an exponential pattern over the course of the next 4 hours. This interval also coincided with an elimination half-life (t1/2 beta) of approximately 0.62 hours for the drug.
• Additional trials with varying infusion rates (13.78, 19.34, and 24.48 micrograms/min/kg) on a single animal showed notably high correlation (correlation coefficient > 0.99) between the dose administered, the resultant steady-state plasma concentrations, and the corresponding areas under the plasma concentration-time curve.

Conclusion

• This research provided significant insights into the pharmacokinetics of ampicillin sodium when given as a continuous intravenous infusion in horses. The regime developed showed a high level of precision, with results aligning quite well with the researchers’ predictions.
• The outcomes from this research can be immensely useful for professionals in the veterinary field when administering ampicillin sodium to horses. It provides a reliable and efficient system for achieving desired therapeutic levels of the medication while minimizing potential risks of underdosing or overdosing.