Chronokinetics of ceftazidime after intramuscular administration to dogs

Ceftazidime pharmacokinetics in dogs after intravenous injection and delivered with the RxActuator Mini-Infuser infusion pump

OBJECTIVE

To test the feasibility of an SC mini-infusion pump to deliver ceftazidime in dogs and produce plasma concentrations sufficient to reach a therapeutic target for 48 hours.

SETTING

University research laboratory.

ANIMALS

Six healthy Beagle dogs.

INTERVENTIONS

Ceftazidime was administered by 2 routes to 6 healthy Beagle dogs. The first route was an IV bolus injection into a cephalic vein at a dose of 25 mg/kg. Blood samples were collected for 8 hours following injection. The second route was a SC infusion for 48 hours using the RxActuator Mini-Infuser wearable SC constant rate infusion pump. Blood samples were collected for 58 hours following application of the pump. All plasma samples were analyzed by high-pressure liquid chromatography and subject to pharmacokinetic analysis.

MAIN RESULTS

After the IV bolus injection, there was rapid distribution and elimination. The elimination half-life was 0.95 hours, and the clearance was rapid at 0.176 ml/h/kg. After the 48-hour SC infusion, the half-life was slightly shorter, and the clearance was higher. The percent bioavailability from the SC infusion was approximately 72%. The SC infusion maintained plasma concentration near our target of 8 μg/ml for most of the dose interval but slightly lower after 24 hours. The concentrations below the target were attributed to slight drug loss, less than 100% bioavailability, and faster clearance from SC administration.

CONCLUSIONS

This study demonstrated the successful application of the RxActuator Mini-Infuser wearable SC constant rate infusion pump for delivering an antimicrobial needed for serious, and sometimes resistant, infections in dogs.