Insulin can be stored out of refrigeration in hot settings!
A team from UNIGE and MSF has shown that a vial of insulin can be stored for 4 weeks after opening and at up to 37掳C,without losing efficacy.
漏 Jinane Saad/MSF
Diabetes requires an extremely precise form of daily treatment, whereby patients have to inject themselves with several doses of insulin every day, which are suited to their diet and physical activity. Patients must therefore keep a supply of insulin which, according to pharmaceutical protocol, must respect the cold chain from production to injection. However, in some regions of the world like sub-Saharan Africa, not every household has a refrigerator.This forces people living with diabetes to go to hospital on a daily basis. Faced with this issue, M茅decins Sans Fronti猫res (MSF) teamed up with the AV短视频 (UNIGE), Switzerland, to test insulin storage in real conditions, that is at temperatures ranging from 25掳C to 37掳C for four weeks. This corresponds to the time it usually takes a diabetic person to finish one vial of insulin. The findings published in the journal PLOS ONE, demonstrate that the stability of insulin stored under these conditions is the same as that of cold-stored insulin, with no impact on efficacy. This allows people with diabetes to manage their illness without having to visit a hospital multiple times daily.
Type 1 diabetes is characterised by elevated blood sugar levels, which can have extremely serious consequences: coma, blindness, amputation or even death. Although it is now possible to treat type 1 diabetes well, it does require daily injections of insulin, which helps sugar enter the body鈥檚 cells. 鈥淭he current pharmaceutical protocol requires insulin vials to be stored between 2掳 and 8掳C until opened, after which most human insulin can be stored at 25掳C for听 4 weeks,鈥� explains Philippa Boulle, a non-communicable diseases advisor at MSF. 鈥淭his is obviously an issue in refugee camps in temperatures hotter than this, where families don鈥檛 have refrigerators.鈥� People with diabetes thus often have to travel to a hospital every day for their insulin injections, which can prevent them from working or force them to travel long distances. 鈥淲e turned to Professor Leonardo Scapozza鈥檚 team to undertake a detailed analysis of the temperature conditions under which insulin can be stored without a reduction in its efficacy,鈥� says Dr Boulle.
Real-life conditions
The MSF team in the Dagahaley refugee camp in northern Kenya found that the temperature in a home fluctuates between 25掳C at night and 37掳C during the day. The researchers then meticulously reproduced these conditions in laboratory setting, where they tested insulin storage. 鈥淎s you can insulin vials can be used for four weeks after opening, we carried out our measurements over the same timeframe, first with vials kept at the temperatures found in Dagahaley, and then with 鈥榗ontrol鈥� vials that were refrigerated,鈥� explains Leonardo Scapozza, a professor of the School of Pharmaceutical Sciences in UNIGE鈥檚 Faculty of Sciences. The UNIGE team used high-performance liquid chromatography to analyse the insulin. 鈥淭he risk is that insulin, a protein, precipitates under the influence of heat.In other words, it would begin to form 鈥榝lakes鈥�. Since the insulin is no longer in solution, it can鈥檛 be injected.鈥�
No difference between the two storage methods
The research results show that all the insulin preparations stored at fluctuating temperatures, as encountered in the field, recorded a potency loss of no more than 1%, just like those kept in cold storage during the required four weeks. 鈥淭he regulation on pharmaceutical preparations allow a loss of up to 5%, so we are well below that,鈥� says Professor Scapozza.
Crucially, the UNIGE researchers also observed that insulin activity was completely maintained. To verify this, they tested the action of insulin proteins on cells, compared with that of insulin that had been intentionally deactivated. 鈥淔inally, with the help of Professor Michelangelo Foti鈥檚 group, we studied insulin vials that came directly from the Dagahaley camp, and always reached the same conclusion: the insulin was perfectly usable,鈥� adds Professor Scapozza.
Results that may change the daily lives of thousands of people
This scientific study has shown for the first time that insulin vials can be used for four weeks even in hot weather without being refrigerated. 鈥淭hese results can serve as a basis for changing diabetes management practices in low-resource settings, since patients won鈥檛 have to go to hospital every day for their insulin injections,鈥� states Dr Boulle. In addition, people with diabetes would no longer be discriminated against and could lead normal lives and work. 鈥淥f course, this will have to go hand-in-hand with educating patients, as well as providing support and follow-ups,鈥� says Dr Boulle, 鈥渟o that people with diabetes can measure their blood sugar levels and inject the right amount of insulin. This will allow people to manage their illness correctly, and more independently. In support of this goal, we hope that a consensus statement will be drawn up, focusing on听 the at-home use of insulin in hightemperature settings when there is no refrigeration available, and that it will be endorsed by the WHO.鈥�