Storage of insulin for the treatment of Diabetes in the community

By chikondi chimbatata | 11 Dec, 2017

I am a nurse working in children’s ward in one of the hospitals in Malawi. At the facility we manage children with different conditions including diabetes. Children with diabetes are managed with soluble insulin and lente drugs and as you might be aware these drugs need to be kept in the refrigerator. Unfortunately when the patient is discharged, they are given the drug and yet the majority of these patients are villagers who don’t have refrigerators, as such storage of these drugs became a challenge. However, the patients try other means of ensuring that the drugs are kept at a cool place for instance one guardian narrated that they dug a hole underground and bury the medication there and everyday (3 times a day) they pour water on the ground just to ensure that the place is cool. The other guardian said, they put the drug in a clay pot with water in it and the pot is placed under wet river sand. These are some of the traditional ways how guardians store insulin in the village. I am just keen to hear from you guys especially those from low income countries how people keep drugs like insulin in the community. Your comments are highly appreciated.



Melissa Cox Replied at 12:09 AM, 12 Dec 2017

Insulin products that are in use may be kept at 15-25 degrees Celsius for up to 28 days and still maintain potency. Only insulin that is stored for longer than that must be kept refrigerated. I know during the hot season in Malawi that it will get above 25 but your methods of keeping it in a clay pot or river sound perfect for keeps the temperature below 25. At my house in Lilongwe right now it’s 23 degrees.

chikondi chimbatata Replied at 11:42 AM, 12 Dec 2017

oooh this sounds perfect. Thanks melissa for your reply.

James Cheyne Replied at 5:38 AM, 18 Dec 2017

Thank you for the post.

The expanded Programme on Immunization had the same discussion about 30 years ago during the early days of the programme. Similar to insulin, vaccine needs to be kept cold until used. The same solutions were proposed for vaccines at the time using evaporative cooling that cools the inside of an unglazed pot that is 'sweating' on the outside with the 'sweat' evaporating to the outside air. When the external relative humidity is low, say, less that 50%, the temperature inside the pot can be lowered by 3 degrees to 4 degree C. Detailed reference:

For example, if the outside temperature is 30 degrees C the cooling effect will reduce the temperature inside the pot to 26 to 27 degrees C. Not a lot but better than nothing.

The Expanded Programme adopted a different solution that did not unfortunately solve the problem of keeping the vaccine cold at the end of the supply chain. The solution that has been in use for many years is a time.temperature indicator has been added to each vial of vaccine to show when the vaccine in that vial should no longer be used since it has passed its time.temperature limit. For example see:

Some vaccine are very heat sensitive and can only survive a few days outside the cold chain, other vaccines can be kept for severals weeks or months at typical tropical ambient temperatures before that are irreversibly damaged. Can insulin survive days or weeks outside the recommended temperature?

If the time-temperature profile of each manufacturer's insulin is known a monitor needs to be added so that the person administering the insulin can know when whether that insulin vial can be used and when to dispose of it and replace it.

This will not be a quick solution but the EPI has shown that it is a workable and affordable solution that prevents heat damaged vaccines being used. Thus everybody can be confident that each dose of insulin is potent when used.

WHO needs to determine the heath stability of each manufacturer's insulin and require that a vial monitor be added.

I hope these thoughts will help in the longer term.

Attached resources:

Melissa Cox Replied at 7:00 AM, 18 Dec 2017

Most insulin products are stable at room temperature for 28-42 days. I've
attached a chart that should be helpful to you.

James Cheyne Replied at 8:10 AM, 18 Dec 2017


Thank you. This is excellent news. I regret that I couldn't see your attachment and I assume that 'room temperature' refers to 20 to 25 degrees C while 'room temperatures' in tropical climates can reach 35 to 40 degrees C.

The WHO specifications for existing Vaccine Vial Monitors can be been at:
and it seems that insulin may be need a monitor similar to the one that is already used to track heat damage on the most stable vaccines.

To be sure to specify the right monitor for insulin the full time-temperature degradation curve would be needed from cool temperatures (e.g 4 degrees C) to hot room temperatures (e,g. 35 degrees C and above). Vaccines degrade with a curve similar to an arrhenius plot. Perhaps insulin does too.

Q: is insulin also damaged by freezing, please? If so, this could be a problem if the insulin is distributed in a classical cold chan. Too much vaccine is still frozen during transport and in refrigerators.

TempTime Corporation has been supplying millions of VVMs for years. They may be able to help if a special indicator is needed for insulin: There are other suppliers too but I know less about them.

Please note, I have no commercial or any other interest in the TempTime Corporation, or any other indicator manufacturer. I am just a freelance cold chain consultant working with years of experience in WHO and PATH with an interest in reducing the use of damaged vaccines and drugs.


Attached resources:

Melissa Cox Replied at 8:23 AM, 18 Dec 2017

Sorry the attachment didn't make it. Here it is again. Yes, it assumes a room temperature of 20-25 degrees which I agree is pretty cool for the tropics but I think its attainable using the low tech methods Chikondi originally mentioned. Maybe someone should do a little study and see?

Attached resource:

James Cheyne Replied at 10:04 AM, 18 Dec 2017


Thank you for the attachment. This is very complete and helpful.

Yes, a field test of 'sweaty pots cooling ' could be useful although the physics of evaporative cooling tells us that this system can only, even under ideal conditions, achieve a temperature drop of 3 to 4 degrees below ambient temperature when humidity is low. In humid conditions the temperature drop will be smaller. Worth a field text, though.

Insulin vial monitors won’t keep the vials cool of course but they do warn the user when not to use a vial that has been over-exposed to higher temperatures. Perhaps a way forward may be to test and promote evaporative cooling in developing country settings AND add a monitor to the vials. This way the evaporative cooling could extend the life of the insulin and the user would know whether the vial on hand is good to use or not.

At a cost of '...adding only few cents per vial...' (Ref: the user can be confident that the insulin that s/he is using is still good to use.


Attached resource:

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