Dose-Drawing Question

Jenna Josie

Jenna Josie

Active Member
So this is embarrassing, seeing as I've been at this for months! (from a thread by Asiina & Alex):

Djamila said:
6. When drawing the dose: 1) draw air into the syringe to the dose you want. 2) while the vial is sitting on the counter, insert the needle into the rubber stopper, and inject the air from the syringe into the air in the vial (not into the insulin itself). 3) invert the vial and draw out the dose.
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I never knew this! What does injecting air into the insulin itself do?
 
Speculation here: 1. greater exposure of insulin molecules to air and possible contaminants; 2. more agitation of said molecules from air bubbling through it (hence more possibility of mechanical denaturing of the insulin molecules).
 
Ummm....yah....what Kris said....:bookworm::bookworm::bookworm:

(my vet just told me to be sure not to inject air into it because it would "ruin it"....I honestly don't know. But I like what Kris said)
 
Okay.....now IM confused LOL! I thought we were supposed to inject air into the bottle before drawing?! The way I read what Kris the scientist wrote I interpret exactly the opposite. Can someone clarify? To air or not to air? That is the question. o_O Is her response to inject into the bottle but NOT the actual insulin? Or no air at all anywhere ?I've been objecting into bottle only which I think is correct. Dang ladies some of you are so smart I think I need to go back to school ! I used to consider myself pretty smart till I joined this group
 
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Lisa and little said:
Is her response to inject into the bottle but NOT the actual insulin?
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Yes, although when you're withdrawing only a very tiny amount from the vial you won't get much, if any, partial vacuum inside the vial working against you drawing the insulin out. It's that partial vacuum the injected air is meant to prevent. That means you can do without the injection of air into the bottle. If you were trying to withdraw half the vial's contents into one syringe you might feel the effects of that vacuum.
 
Funny story - when I first started years ago, no one ever told me to equalize the pressure by inserting air into the vial. When I got to the last 1/4th of the vial, every time I'd pull the dose and let go, the internal pressure inside the vial would suck it right back out. I was SO confused as to what was happening. :) 'Course I'm easily confused...
 
I do cat rescue and do this with vaccine vials to draw up the sterile diluent faster. It's such a minute amount with the insulin I haven't done it....yet.
 
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"Mechanical denaturing" is the phrase of the week! :D (It does sound a little naughty, though, out of context . . . )

Thanks, Kris.

P.S. I wrote this post hours ago but neglected to post it! When I looked back at the thread when new posts came in, I thought I'd been censored lol. And I was all, It wasn't me who said that! It was Kris! It was Kris!
 
Jenna Josie said:
"Mechanical denaturing" is the phrase of the week! :D (It does sound a little naughty, though, out of context . . . )

Thanks, Kris.

P.S. I wrote this post hours ago but neglected to post it! When I looked back at the thread when new posts came in, I thought I'd been censored lol. And I was all, It wasn't me who said that! It was Kris! It was Kris!
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This is hilarious! :woot::smuggrin: "Mechanical denaturing" is a thing: complex protein molecules (like insulin) need a certain structure to do their job and that structure can be disrupted by heat, wrong level of acidity (I almost said pH ;)) , vigorous jostling (mechanical denaturing) and so on.

Ever the science nerd ...
 
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