Devices and Methods for Maintenance of Temperature and Pressure During Islet Shipment

Exposure to extreme temperatures and pressure fluctuations during shipment by air may have a detrimental impact on islet quality. In this study, we sought to assess the ability of methods and devices to provide better control of the internal environment of islet shipping containers in terms of temperature and pressure. Methods: Experimental islet shipping containers were packed with 21 panels of commercially available TCP Phase 22 Phase Change Material (TCP). The containers were then exposed for at least 15 hours to three constant external temperature conditions, namely, -20°C, 4°C, and 40°C, and then evaluated for their ability to maintain an internal temperature close to the desired value of 22°C. Custom-designed pressure regulated gyroscopic shipping containers (PRGSC) placed in a vacuum chamber were exposed to an absolute pressure of 250 mm Hg (substantially lower than that experienced during shipment by air) for 25 minutes to assess their ability to control internal pressure under vacuum. Electronic data loggers were used to monitor internal and external temperatures and pressures under all conditions. Results: Twenty-one TCP panels placed in a single islet shipping container were able to maintain the internal temperature between 17°C and 24°C for a minimum of 15 hours at all three external temperatures. The PRGSC tested were able to maintain a constant internal pressure of 760 mm Hg when exposed to vacuum. Conclusions: Our results demonstrated that the use of containers equipped with TCP and PRGSC exert excellent environmental control over islet shipments by minimizing temperature and eliminating pressure fluctuations.