Everything in the opening post holds. The case it does not cover is the one I have. Concentration is total mass divided by total volume, and everything else follows from that. Ten milligrams into two millilitres is five milligrams per millilitre, and it does not matter how the vial was labelled before you added…
On the subject in the title: Choosing a concentration on purpose rather than by accident Working notes rather than a conclusion.
Working notes on choosing a concentration rather than a conclusion. I would rather post the reasoning while it can still be corrected than post the answer once I am committed to it.
Everything below is checkable. Where I have taken a figure from somewhere else I have said where; where I have estimated, I have said that too.
Everything in the opening post holds. The case it does not cover is the one I have.
Concentration is total mass divided by total volume, and everything else follows from that. Ten milligrams into two millilitres is five milligrams per millilitre, and it does not matter how the vial was labelled before you added anything.
I am reporting what happened, not recommending it.
A 10 mg vial reconstituted three different ways: 1 mL diluent gives 10 mg/mL, 2 mL gives 5 mg/mL, 4 mL gives roughly 2.5 mg/mL. The arithmetic is the same; the concentration determines which syringe graduations are legible.
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