Stability of vincristine sulfate, doxorubicin hydrochloride and etoposide phosphate admixtures in polyisoprene elastomeric pump supporting transition of the EPOCH regimen to outpatient care.

Background: The EPOCH regimen, consisting of vincristine sulfate, doxorubicin hydrochloride, and etoposide phosphate, is typically administered by continuous infusion over four days to oncology inpatients. If the EPOCH regimen was available to be administered through portable elastomeric pumps, chemotherapy could be transitioned to an outpatient setting, reducing inpatient bed days and overall healthcare costs. However, a lack of stability data for the admixtures in the elastomeric infusion devices currently prevents the transition of the regime to an outpatient setting. The purpose of this study is to determine the physical and chemical stability of the admixture in polyisoprene elastomeric pumps under different storage conditions to support the transition of the EPOCH regime to an outpatient setting.

Methods: The physico-chemical stability of three admixtures at a range of clinically relevant concentrations compounded in polyisoprene elastomeric infusors was determined when refrigerated at 2-6℃ over a 14-day period followed by 35℃ up to 7 days in the dark, and under standardized fluorescent light to simulate scenarios in clinical practice.

Results: All tested admixtures were compatible and the drugs were stable in the elastomeric infusors for up to 14 days when stored at 2-6℃ followed by 7 days at 35℃ in the dark, with nominal losses of <5%. The major degradant of etoposide phosphate was its active form etoposide. There was no degradation (<1% loss) found when the admixture was exposed to a standardized fluorescent light dose of 80 klux-h (25℃) for 10 h. The temperature and light conditions the infusors were exposed to during the stability study were more severe than the conditions determine during clinical administration.

Conclusion: The extended stability of the three infusional admixtures compounded in elastomeric infusion pumps demonstrated herein permits advance preparation and storage of these drugs, reducing pharmacy compounding resources. The demonstrated stability at 35℃ and under light exposure, conditions more severe than those experienced during clinical practice, support continuous infusions for up to seven days from the elastomeric infusors without a loss of potency. The proven stability of the EPOCH regimens in the tested elastomeric infusion device supports the transition of treatment to an outpatient setting which will reduce inpatient bed days and overall healthcare costs.