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#reconstitution 2025-04-08
Tuesday45 messages11 participantstimes are UTC
Highlights from this day
- salt_bridge — do you draw up with the same pin you inject with 20:42
- tokyo_taper — lyophilised powder is far more robust than people think. it is the solution that is fragile 21:03
- salt_bridge — sorry to jump in update from 16 months ago: switched to a single concentration and have not miscalculated since, take that with a pinch of salt 21:31
- blank_run — gross powder mass is not net peptide. water and counterion are in that number, ill dig out the number 22:18
is it normal for the cake to look slightly collapsed on one side
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too dilute imo
i write the mg/ml on the vial with a sharpie the moment i reconstitute it
15mg in 3ml is 5mg/ml. same numbers as 10 in 2, just more of it
10mg vial
+ 1.0ml -> 10.0 mg/ml 0.5mg = 5u 1mg = 10u
+ 2.0ml -> 5.0 mg/ml 0.5mg = 10u 1mg = 20u
+ 2.5ml -> 4.0 mg/ml 0.5mg = 12.5u (dont)
+ 5.0ml -> 2.0 mg/ml 0.5mg = 25u 1mg = 50ucoming back after 21 months, has the pinned recon volume advice changed
anyone got a photo of what a properly dissolved vial looks like
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one unit is 0.01ml. 100 units is 1ml. everything else in this channel follows from that
i use bac water even for a single-use vial because it stings less, which is not the reason it exists
it should be completely clear with no floaters. cloudy means stop
nope, redo it
my vial pulled the water in on its own, is that the vacuum or did i do something
does benzyl alcohol matter if im finishing the vial in one go
is a slightly cloudy solution ever ok or is that always a bin it
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do you let it come to room temp before drawing or draw it cold
how much do i lose to dead space with a 30G pin
label the vial
if i add 2ml to a 15mg vial what concentration am i actually at
a 3ml syringe for the diluent and a u100 for the dose is the setup most people here end up with
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Reminder set. I will post here in 3 days.
anyone worked out a recon volume that puts 7.5mg on a round unit mark
[edited]5mg in 2ml gives 2.5mg/ml, 0.25mg is 10 units. good for a starting dose
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benzyl alcohol is what makes it bacteriostatic. it is about 0.9% typically, thats one data point
if you draw up with a bigger pin and inject with a fresh one you lose a bit more to dead space
do you draw up with the same pin you inject with
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anyone else find the 2mg vials harder to get fully dissolved than the small ones
how do you all measure a half unit, or do you just not
what do you do with the last 30 units when you cant draw them cleanly
lyophilised powder is far more robust than people think. it is the solution that is fragile
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label the date too. you will not remember which vial is which by week 15
my 10mg vial weighed 11.4g on the jewellery scale, is that wrong
swirl dont shake
coming back to this the jewellery scale is a good habit but calibrate it, they drift badly
i swirl for about thirty seconds and then leave it. never had one fail to dissolve, thats one data point
do i swirl for a specific length of time or just until its clear
i keep a spare vial of bac water in the fridge purely so i never rush the maths
sorry to jump in update from 16 months ago: switched to a single concentration and have not miscalculated since, take that with a pinch of salt
10mg vial
+ 1.0ml -> 10.0 mg/ml 0.5mg = 5u 1mg = 10u
+ 2.0ml -> 5.0 mg/ml 0.5mg = 10u 1mg = 20u
+ 2.5ml -> 4.0 mg/ml 0.5mg = 12.5u (dont)
+ 5.0ml -> 2.0 mg/ml 0.5mg = 25u 1mg = 50u💀1👀7
write the date on
not sterile water
does it matter if i inject the bac water straight at the powder
thats fine
[edited]if you cannot read the mark confidently, your volume is too small. redo it at a lower concentration
gross powder mass is not net peptide. water and counterion are in that number, ill dig out the number
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dead space in a standard insulin syringe hub is small but it is not nothing over a month
give it 5 minutes at room temperature before you decide it has not dissolved