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c/reconstitution·submitted 2 years ago by u/quarter_dose_queen

[Question] how do you actually verify concentration

Questionbranch of 13 comments

Been lurking in c/semaglutide for about 21 months and finally have something worth posting. Short version: week 51, 5mg, and mg/mL is the bit I still cannot get a straight answer on. I have read the wiki, I have read the last 35 threads, and the answers split roughly down the middle. What I actually want to know is…

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13 comments, started 2 years ago
u/alcohol_aversion153 points·2 years ago

Dead space in the needle hub holds a small but non-trivial volume. On low-volume draws that can be several units.

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u/aurel_boateng92 points·2 years ago

The single most useful thing I did was write the concentration on the vial. Stopped all the confusion after that.

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u/aleksi_lehtinen32 points·2 years ago

i am begging people to write down the concentration

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u/dilara_szabo20 points·2 years ago

Not convinced. The evidence does not support that reading.

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u/arne_restrepo117 points·2 years ago

This is correct. 2mL versus 2mL is the common mistake.

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u/elodie_grimaldi138 points·2 years ago

This is the "correlation is mechanism" thing again. You changed three variables at once.

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u/quiet_reader_9942 points·2 years ago

dead space is real and the syringe matters

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u/britta_nakamura53 points·2 years ago

Show the arithmetic. Where did the units come from?

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u/sleep_apnea_sam35 points·2 years ago

the concentration on the vial in marker is the most important step

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u/signe_grimaldi22 points·2 years ago

the concentration on the vial in marker is the most important step

Disagree on that part. 99.3% and 93.7% on the same vial is normal.

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u/reflux_report10 points·2 years ago

swirl, do not shake, or you are courting oxidation

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u/india_generic_g81 points·2 years ago

Dead space in the needle hub holds a small but non-trivial volume.

Yes, exactly this, and it is the bit that took me 65 weeks to accept.

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u/janek_ferrari22 points·2 years ago

15mg vial, 1mL water, concentration is 15/1 — write it on the vial afterwards

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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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