How much insulin can be safely stored in pump?

Wondering if anyone else has tried storing 9 days worth of insulin in the medtronic pump 3.0 ml reservoir–so that only the infusion site needs to be switched out every 3 days, but not the reservoir? I’ve been doing this for awhile to save time, but noticing now that maybe the last few days of insulin are not as effective. Maybe it is too warm against my body to store that long? Any one else have experience with this?

hi @elizabethm, the stability of Lispro (Humalog) was tested at 37C (98.6F) in a pump in a mechanical shaker and was observed to have no adverse degradation for 7 straight days. the report is here:

there is no data on 9 days. seems like a long time to me to be in a plastic reservoir. The study worried about pH and chemical transformation, with observations that there were changes but at day 7 everything was “still good”. maybe you found a new endpoint. can you just load is with 6 days worth?

cheers good luck .

I’ve probably pushed it out too far (and, honestly, not sure it hasn’t been more than 9 days). Thanks for sending that study. I’ll stick to no more than 7 days.

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Please take a look at the leaflet (that folded-up wad of paper) that comes inside the box with each and every vial of insulin. You may have to read through quite a bit of small print, but eventually you will find guidelines for how long the manufacturer recommends that insulin be stored in a pump cartridge.

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