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c/reconstitution·submitted 1 year ago by u/honest_syringe_2025

[Meta] the concentration rule is doing its job and people should stop complaining

Mathbranch of 9 comments

the concentration rule is doing its job and people should stop complaining — with the counter-argument included, because I find it fairly persuasive. Wrote the date on the vial as well as the concentration after losing track of which one was opened first. Asked MKM what volume they reconstitute to for their own…

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9 comments, started 1 year ago
u/tl_dr_tina176 points·1 year ago

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.

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u/arne_restrepo56 points·1 year ago

Aim the stream down the wall of the vial rather than into the cake.

Adding one thing — put the date on the label too. Concentration plus date and you can never mix two vials up.

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u/zaid_balogun33 points·1 year ago

I would not round that figure. At 30mg/mL a rounding error of two units is a real fraction of the intended amount.

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u/emil_okwuosa145 points·1 year ago

Reconstituted at 3mL when I meant to use a different volume. Caught it because the units looked wrong on the barrel. Now I write 10mg/mL on the glass before I put the cap back.

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u/honest_syringe_2025OP103 points·1 year ago

That is sterile water, not bacteriostatic. Same appearance, different product, and it matters for a multi-draw vial.

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u/niels_roos41 points·1 year ago

the number you write down is the number you will trust at 6am

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u/santiago_ndiaye80 points·1 year ago

a U-100 syringe reads 100 units to the millilitre, every time

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u/zaid_balogun-10 points·1 year ago

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.

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u/honest_syringe_2025OP59 points·1 year ago

What concentration did you actually reconstitute at, rather than what did you intend to?

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About c/reconstitution

The arithmetic and the technique. Bacteriostatic versus sterile water, reconstitution volume as a concentration choice, converting mg/mL into insulin-syringe units, dead space, swirl-not-shake, stopper coring, and how long a reconstituted vial is actually good for. Math errors get corrected fast and politely.

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