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c/reconstitution·submitted 14 days ago by u/sleep_apnea_sam

cloudy after reconstitution — discard, right? right.

Correctionbranch of 10 comments

cloudy after reconstitution — discard, right? right. Not a hot take, just something I have not seen said plainly here. 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. Why "more…

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10 comments, started 12 days ago
u/cardio_endpoint_c72 points·12 days ago

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.

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u/elin_ferrari49 points·12 days ago

Bacteriostatic or plain sterile water?

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u/emeka_delgado20 points·12 days ago

label the vial with the date as well as the concentration

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u/quarter_dose_queenlow and slow5 points·12 days ago

Asked SGN what volume they reconstitute to for their own stability testing and they answered in one line. Useful thing to know.

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u/emil_zamora2 points·11 days ago

twice as much water halves the concentration and doubles the units for the same dose

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u/ledger_modmod · vetting57 points·12 days ago

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.

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u/gradient_goblin47 points·12 days ago

bacteriostatic water has the preservative, sterile water does not

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u/emil_wojcik44 points·12 days ago

if the maths gives you a fraction of a unit, change the concentration

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u/niels_roos14 points·12 days ago

dead space in the needle hub is real and it is small

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u/santiago_ndiaye27 points·12 days ago

Show the arithmetic — where did the unit figure come from?

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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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