[Question] how do you actually verify reconstitution
The title is the whole question — how do you actually verify reconstitution — but here is why I am asking.
Research-use-only material is not approved for human use, so treat everything in this thread as arithmetic about solutions rather than instructions for a person.
If your calculation produces a fraction of a unit, the concentration is wrong for your dose. Change the water volume until the numbers land on whole units.
Aim the stream down the wall of the vial rather than into the cake. Reconstitution is a solubility problem, not a mixing problem, and mechanical shear does nothing helpful.
Not medical advice, obviously, and nothing here is approved for human use. One person with a spreadsheet.
best — the order this archive was captured in
Working has to be shown on arithmetic posts. Added a note asking for it rather than removing this one.
The failure modes I have actually seen posted here, in order of frequency.
One: reconstituting at a different volume than intended and not writing it down, so the next draw is based on a remembered concentration. Two: treating units as a dose rather than a volume, which breaks the moment the concentration changes. Three: assuming a syringe is U-100 when it is not.
All three are solved by the same two habits — do the arithmetic before the water goes in, and write the result on the glass. Neither costs anything and between them they cover almost every question this board gets.
The failure modes I have actually seen posted here, in order of frequency.
This is the sentence that makes the rest unnecessary. Write it on the vial and the problem is gone.
Bacteriostatic water contains benzyl alcohol as a preservative, which is what makes repeated entry into the same vial reasonable. Plain sterile water has no preservative.
write the concentration on the vial in marker, that is the whole post
label the vial with the date as well as the concentration
label the vial with the date as well as the concentration
Adding one thing — put the date on the label too. Concentration plus date and you can never mix two vials up.
Adding one thing — put the date on the label too.
Right, and the arithmetic behind it: 5mg in 1mL is 5mg/mL, so 2mg is 40 units.
label the vial with the date as well as the concentration
kavya_radich has the units point exactly right. They are a volume on the barrel and nothing else.
That is sterile water, not bacteriostatic. Same appearance, different product, and it matters for a multi-draw vial.
The lyophilised cake displaces a small volume, so the true concentration is very slightly lower than the arithmetic suggests. It is a fraction of a percent and it is dwarfed by fill tolerance.
Agreed — units are volume. Once that lands, the rest of the arithmetic is one division.
Is that a U-100 syringe? The barrel markings change the answer completely.
I keep a laminated card in the drawer with the arithmetic on it. Looks ridiculous. Has never once let me draw the wrong volume.
Adding more water does not change how much peptide is in the vial. It changes the concentration, which changes the volume you draw for the same amount. That is the entire relationship.