Stability of intravenous medicines - evidence of maximum temperature reached in both summer and winter within soft shell elastomeric pumps.

Objective: Elastomeric devices or pumps are a valuable tool to deliver outpatient parenteral therapy and have been used for administration of chemotherapy, antibiotics and pain medication. A key determinant of effective treatment is to consider the stability of medicines within these devices. It is widely known that an increase in temperature positively correlates to an increase in drug degradation. The objective of our work was to measure the temperature within soft shell elastomeric devices, under simulated outpatient treatment conditions in summer and winter months, and to determine the maximum temperature reached within these periods of use.

Methods: Thermocouples were inserted within soft shell Easypump II (B Braun Medical, Sheffield, UK) elastomeric pumps and the temperature was monitored under simulated outpatient conditions during cold and warm weather with different fill volumes. Temperature monitoring was also conducted with varying levels of insulation around the devices.

Results: Our results show that internal temperatures remained below 32°C±1°C in winter and summer months, including during times defined as a heatwave. Fill volume and ambient temperature were shown to be significant factors affecting the internal temperatures reached.

Conclusion: A soft shell Easypump II elastomeric pump, if used within its carry pouch, will maintain the internal solution below a temperature of 32°C±1°C if patients correctly adhere to handling guidance. Our results show that further improvements to the insulation material used in carry pouches can significantly restrict the rate of temperature rise within the pumps and will give more assurance in relation to preventing degradation especially considering the increases in extreme weather conditions observed in recent years due to global warming.