Stability of milrinone in continuous ambulatory delivery devices

Purpose. The stability of milrinone in continuous ambulatory delivery devices (CADDs) stored at 4, 25, and 35 °C was evaluated.

Method. Six CADDs (3 devices containing milrinone plus 0.9% sodium chloride injection and 3 devices containing milrinone plus 5% dextrose injection) were prepared. Devices were kept at 4 °C for 168 hours, followed by 24 hours at 25 °C and an additional 24 hours at 35 °C. Samples (n = 3) were withdrawn aseptically at 0, 24, 48, 72, 96, 120, 144, and 168 hours from the CADDs stored at 4 °C and at 0, 6, and 24 hours from the CADDs stored at 25 and 35 °C. The milrinone concentration of each aliquot was analyzed using a stability-indicating high performance liquid chromatographic method within 15–30 minutes of preparation. The samples were also evaluated for changes in pH, changes in color, and particulate content. Six control samples (3 containing 0.9% sodium chloride injection and 3 containing 5% dextrose injection) were prepared and similarly analyzed.

Results. Milrinone admixtures retained more than 99% of their initial concentration for 168 hours at 4 °C and for 24 hours when stored at 25 and 35 °C. No evidence of particle formation, color change, or pH change was observed throughout the study period.

Conclusion. Milrinone 600 mg/mL prepared in either 0.9% sodium chloride injection or 5% dextrose injection in CADDs was stable for 168 hours when stored at 4 °C and for 24 hours when stored at 25 and 35 °C.