if you draw up with a bigger pin and inject with a fresh one you lose a bit more to dead space
#reconstitution 2026-04-07
Tuesday57 messages9 participantstimes are UTC
Highlights from this day
- point_two_five — a 3ml syringe for the diluent and a u100 for the dose is the setup most people here end up with if you cannot read the mark confidently, your volume is too small.… 13:12
- point_two_five — nobody here should be telling you a dose. we can check your arithmetic, thats a different thing, from memory 14:41
- quiet.hours — 10mg in 1ml is 10mg/ml, so 2.5mg is 25 units. thats the one i use 17:38
- assay_not_purity — slightly off topic but it should be completely clear with no floaters. cloudy means stop 19:49
the meniscus thing is real. read it at eye level or you are guessing by a unit either way, not advice obviously
how long after reconstituting before its actually dissolved
read it at eye level
20mg in 2ml is 10mg/ml. 1mg is 10 units, 2mg is 20 units, easy
weigh it first
label the date too. you will not remember which vial is which by week 25
12:30quiet.hours pinned a message to this channel
bacteriostatic water for anything multi-use. sterile water has no preservative in it at all
i swirl for about thirty seconds and then leave it. never had one fail to dissolve
lyophilised powder is far more robust than people think. it is the solution that is fragile
took me a year to stop over-diluting. the measurement error at 4 units is worse than the convenience, still working it out
do you let it come to room temp before drawing or draw it cold
the last few units are a real loss. i accept it rather than tilting the vial and drawing air
do not add more bac water to an already reconstituted vial, you have lost track of the concentration, i could be wrong
right so how much do i lose to dead space with a 29G pin
a 3ml syringe for the diluent and a u100 for the dose is the setup most people here end up with
if you cannot read the mark confidently, your volume is too small. redo it at a lower concentration
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a slightly collapsed cake is cosmetic. a puddle in the bottom is not
[edited]quick one benzyl alcohol is what makes it bacteriostatic. it is about 0.9% typically
bac water or sterile water for something im going into weekly for 3 weeks
point_two_fivedo not add more bac water to an already reconstituted vial, you have lost track of the…
whats the smallest volume you would trust yourself to measure on a u100
not sterile water
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my vial pulled the water in on its own, is that the vacuum or did i do something
do you draw up with the same pin you inject with
temperature of the diluent does not matter. how fast you push it in does
thats fine
[edited]aim the diluent at the glass wall, not at the powder. it goes in gentler
what do you do with the last 50 units when you cant draw them cleanly
one unit is 0.01ml
how do you all measure a half unit, or do you just not
label the vial
nobody here should be telling you a dose. we can check your arithmetic, thats a different thing, from memory
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the powder is stuck to the stopper, do i care
[edited]14:45quiet.hours pinned a message to this channel
15mg in 3ml is 5mg/ml. same numbers as 10 in 2, just more of it, from memory
slightly off topic but 10mg in 2ml is 5mg/ml. so 0.5mg is 0.1ml which is 10 units on a u100, ymmv
Inter-lab diff for lot SG-1177: 99.4% vs 98.6%. Within expected range.
if you cannot read the mark confidently, your volume is too small. redo it at a lower concentration
thats 5mg/ml
if the powder is on the stopper, tap it down before you add anything. it will still dissolve either way
dead space
write the date on
thats the vacuum
follow up pick the volume so your dose is a whole number of units. thats the entire trick
10mg in 1ml is 10mg/ml, so 2.5mg is 25 units. thats the one i use
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if the maths gives you 13.7 units, change the volume. do not try to hit 13.7
swirl it. do not shake it. the foam is denatured protein and you are not getting it back
lyophilised powder is far more robust than people think. it is the solution that is fragile
i keep a spare vial of bac water in the fridge purely so i never rush the maths
label the date too. you will not remember which vial is which by week 3
right so update from 7 months ago: switched to a single concentration and have not miscalculated since
bac water
slightly off topic but it should be completely clear with no floaters. cloudy means stop
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one unit is 0.01ml. 100 units is 1ml. everything else in this channel follows from that
weighing the vial before you reconstitute is the only way to catch an underfill, happy to be corrected
sorry to jump in i write the mg/ml on the vial with a sharpie the moment i reconstitute it
coming back to this do i swirl for a specific length of time or just until its clear