This is all conjecture w/o clinical support and is a waste of time and energy. Look at the Insulin manufacturers documents, and the designs of longer lasting infusion set using the same pumps and insulins.
Good discussion, thank you.
This video is about the set and cannula that Tandem and has yet to release. It was approved by the FDA last summer and has yet to be shipped. I had a great discussion about it with one of the engineers who was involved in the design and moved over to Tandem to get the product to market. I was able to see it at FFL on Orlando last year. It is also part of the line free 7 day site set for the Mobi.
Reposting Mark Estesâ video with some notes I took that are relevant to this discussion.
I wouldâve preferred to be able to post from a transcript of Estesâ talk, but unable to find it. Below are my notes the best I could do. The period of 10 minutes 30 seconds to 20 minutes is most interesting especially in the matter of preservative loss not my an interaction with the plastics, but by the migration of preservatives into and then to the air through the plastics.
At 10:38 - He puts up a slide on. Inflammation and the causes wounding, the intrusion of a foreign object (the cannula) and preservatives.
!5:10 - Slide, for insulin to work properly preservative levels must be maintained.
16:02 - Preservatives prefer migrating into plastics over staying in solution with insulin.
16:17 - Some plastics are more attractive to preservatives. The preservatives migrate to the plastic, but also will then evaporate into the air from the plastics. As the insulin losses preservatives there is a a cascading effect that cause increased breakdown of the remaining preservatives in the insulin.
He goes on to say that air even in microbubbles in the insulin will contribute to degrading the quality of insulin as well as cascading.
Edit - I left out that he mentioned temperature also causes the degradation of insulin. This is important because many of us especially Pod, Twiist and Mobi wear pumps with close body contact.
Just a note, Mobi like Medtronic or whatever they call themselves and Omnipod do not use a collapsible bladder reservoir.
Mobi is plastic, syringe not bladder. Does not have an impact and studies note were focused on tubes as suspect. But not with insulin. The Mobi 7 day set will have no tube.
This description is not a clear overview and misses some important info about how the multiport cannula improves absorption. Due to the age of the presentation, there has been additional info published, and the company was purchased by Tandem. Current production issues appear to be causing a significant delay in the release date. Mobi will be the first product release. The preservative is not impacting the efficacy of the insulin as much as causing the fat tissue scarring and poor absorption. As with the Medtronic 7-day, limiting the passing through of the insulin preservative helps minimize the tissue damage, and the multiport helps distribute the insulin over a greater area of fat tissue and improves the conversion of the insulin into signal molecules so it can be used.