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> I agree with Randall, that until there is some real evidence that a:
> Humalog is unstable or b: that buffering would really help, Lilly is not
> likely to make any changes.  I, for one, have described my own
> quasi-scientific evidence that mixing a little of the buffered V with H
> doesn't do anything.  But I know others have very different religious
> beliefs about this.

> Since I've been on this list, though, I've yet to see any concern that
> there is clogging in the tubing with H. This apparently was a problem with
> older tubing, but the new double thickness tubing seems to have overcome
> this.  There can be problems at the tip, but this is a different problem.
> - -wm

I'm pretty confused here, along with everyone else. I believe that
Humalog and Velosulin are both buffered, and are the only buffered
insulins on the market. But I may be wrong...

What does buffered mean? Don't really know. Others seem to use the term
as if they know what it means. My limited knowledge of chemistry tells
me that adding certain chemicals to a solution can stop crystals
forming, like the crystals that form in an old tin of corn syrup or jam.
Insulin has a habit of forming crystals: that's what the cloudy white
stuff is in NPH insulin. Solid crystals of insulin, which slowly
dissolve once under the skin. These crystals used to form quite quickly
in the old pump tubings, which is why Novo produced a special "buffered"
pump insulin called velosulin. But the new tubings actively prevent
crystals forming, so the use of buffered insulins is thought to be no
longer so important.

I go through periods of having No Delivery alarms. An ND is not always
caused by a crystalisation blockage. On many occasions I've narrowed it
down to the cartridge plunger sticking. On a handful of occasions I've
found a blockage caused by a small ammount of white stuff plugged in the
very tip of the cannula. It was my feeling that this was not insulin
crystals, but a fatty deposit by the immune system, as it attempts to
isolate this foreign body that has been stuck under the skin. Some have
described this white stuff being coated to the outside of the cannula as
well on occasions.

Some, but not all, find this rejection of the cannula and infusion site,
when it occurs, is reduced by mixing a small amount of Velosulin or
Regular with the Humalog. Why this works is not understood, nor will
doctors actively promote this until it is further studied. But it seems
to be risk free. Go figure...

(who really is taking Mac in for repairs now...)
mailto:email @ redacted

Insulin-Pumpers website http://www.bizsystems.com/Diabetes/