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Practice · Reconstitution · continued

A 10 mg vial reconstituted three different ways, compared posts 31–35

This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.

OO
orbitrap_olaTL3Mass spectrometrist9 Jul 2026#31

A vial that will not fully dissolve: check in order: is the diluent genuinely room temperature (some preservatives crystallise in cold), is the vial being warmed gently rather than shaken hard, is the injection technique clean, is the vial integrity intact. Work through that checklist before concluding the powder is insoluble.

1 like 19d
NB
n.brobergTL2 Moderator13 Jul 2026#32

Over-dilution: if your target dose is 0.25 mg and your syringe is a 1 mL insulin syringe, you need a concentration high enough that 0.25 mg fits on the scale. A 0.25 mg/mL solution requires drawing the entire 1 mL syringe — not readable. A 5 mg/mL solution requires drawing 50 μL — also not practical on an insulin syringe.

0 likes 15d
DS
dr_seongTL3Physician18 Jul 2026#33
a.teixeira, post #13: Choosing a concentration on purpose rather than by accident: starting with "I want to draw 0.5 mL per dose" and working backward to the required concentration is more efficient than picking a diluent volume and hoping the math works out. State your target volume, then the required concentration follows. Go to post

I read post #31 twice before replying, because I had assumed the opposite.

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

17 likes in reply to #13 10d
IA
i.almeidaTL2 Moderator23 Jul 2026#34

This follows post #31 rather than contradicting it.

Reconstituting a multi-strength kit: if a kit contains 5 mg, 10 mg, 15 mg vials and you are reconstituting all of them, writing the concentration on each vial in permanent marker as you go is the single most useful thing you can do to avoid dose errors later.

7 likes 5d
DO
dr_okonkwoTL4 Moderator27 Jul 2026#35
Staff post. Actions described here are recorded in the public moderation log and may be challenged in Meta.

Why "add 2 mL" is not an instruction: the powder in the vial takes up space. "Add 2 mL to a 10 mL vial" and "add 2 mL of diluent so the final volume is approximately 2 mL" are different instructions. Stating the final target volume is clearer than stating the diluent added.

0 likes 17h

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