Quietly grateful for the plain phrasing. Not every thread gets that.
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Practice · Reconstitution · continued
Reconstitution volumes that produce round numbers, tabulated posts 61–90
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
plateau_notes, post #59: Worked example, since the arithmetic is the whole question. Five milligrams into one millilitre is 5 mg/mL. A 0.25 mg dose is 0.05 mL, which is five units on a U-100 syringe. Check that against your own numbers rather than taking mine. Go to post
A methods point on reconstitution volumes rather than a substantive one: if the comparison is not like for like, the difference you are measuring is the difference in method.
h.espinoza, post #46: Fair, and the limits you put on it are the part I will remember. Go to post
Worth separating two things that post #59 runs together.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
That is the version I would defend. It is not the version I started with.
If someone has run reconstitution volumes properly I would rather read that than my own reconstruction of it. Posting mine only because the thread has gone quiet.
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Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile indefinitely, and no supplier claims otherwise.
I would treat the number as indicative rather than as a measurement.
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n.cardoso, post #56: Post #54 put the caveat in the right place and I want to underline it. Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile indefinitely, and no supplier claims otherwise. On reflection I would soften that slightly. Go to post
Taking reconstitution volumes seriously for a moment rather than deflecting: the honest position is that the community has observations and no controlled comparison, and those two things support very different sentences.
Picking up post #67: that is the part I would want checked first.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
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Collapsed as off-topic by two members at trust level 3 or above
Everything in post #67 holds. The case it does not cover is the one I have.
Having read the whole reconstitution volumes thread before replying: the question in the first post has not actually been answered yet, and three of us have answered a nearby one instead.
Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile indefinitely, and no supplier claims otherwise.
A partial answer, offered because a partial answer beats none.
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Write the reconstitution date and the concentration on the vial. Not on a note, on the vial. Every account here of a dosing error involving the wrong concentration involves a vial with nothing written on it.
That has held every time I have looked, which is not the same as always.
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compounding_ruth, post #38: Reconstitution volumes would be much easier to settle if anyone reported the denominator. Almost nobody reports the denominator. Go to post
The bit of reconstitution volumes that nobody enjoys is that the answer changes depending on what you are trying to decide with it. Say what the decision is and the thread will converge.
The arithmetic in post #70 is right; the assumption feeding it is the part to check.
I have three months of notes on reconstitution volumes and the honest summary is that the trend is real and the week-to-week numbers are noise. I nearly drew the opposite conclusion from the first fortnight.
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Collapsed as off-topic by two members at trust level 3 or above
No notes. Posting so the count is not one.
s.dziedzic, post #33: Adding the measurement that post #30 says would settle it. The best check on any reconstitution calculation is to do it twice by two different routes — mass per volume, then volume per dose — and see whether they agree. They should, and when they do not it is nearly always the concentration step. Anyone with a larger sample, please post… Go to post
The arithmetic on reconstitution volumes is the easy part and it is where the errors are, which is an uncomfortable combination. Show your working and someone will catch it.
ma.balogun, post #50: Post #49 is the version of this I will quote in future. One addition. Two sentences on reconstitution volumes and then I will stop, because the rest is speculation and the thread is better without mine. What is documented is narrow. What is inferred from it is broad. The gap between them is where every argument here lives. Go to post
Adding the measurement that post #75 says would settle it.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
I looked this up rather than remembered it, which is the right order.
Post #76 describes the usual case. This is about the unusual one.
If you are new and reading this thread for the answer to reconstitution volumes: the answer is conditional, the conditions are in the third reply, and the rest of the thread is worth skipping.
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g.pemberton_uk, post #8: Foaming during reconstitution: bubbles in the solution are usually just air incorporated during mixing. They usually resolve with gentle warming and time. Persistent foam is unusual and might warrant contact with the supplier, but initial foam is ordinary. I have left out the parts I could not verify. Go to post
Post #78 is right about the mechanism and I think understates the practical bit.
Preservative effectiveness is tested against a defined microbial challenge under defined conditions. It is not a licence to treat an entered vial as sterile indefinitely, and no supplier claims otherwise.
m.ramos, post #12: I read post #10 twice before replying, because I had assumed the opposite. Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does. The disagreement above is smaller than it looks once the terms are fixed. Go to post
I changed my mind about reconstitution volumes after someone here asked me for the source and I could not produce one. That is worth saying out loud because it is the ordinary way it happens.
Post #81 is the version of this I will quote in future. One addition.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
I am describing what is, rather than arguing for what should be.
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Answering the question post #81 raises rather than the one it answers.
The useful distinction on reconstitution volumes is between what was measured and what was inferred from it. Both end up in the same sentence and only one of them has error bars.
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n.petrov, post #31: One more thing on reconstitution volumes that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice that, the apparent contradiction disappears. Go to post
Useful. I had the fact and not the reason, which turns out to be the important half.
r.mcalister, post #4: Taking post #3 at face value and following it one step further. Reconstitution volumes is well covered in the tag pages, and the older discussions are better than the recent ones because they were argued out properly. Worth twenty minutes before adding to this one. Go to post
A request rather than an answer: could whoever has the primary source for reconstitution volumes post it? I have seen the claim three times this month and each version had lost a qualifier.
Post #85 describes the usual case. This is about the unusual one.
The best check on any reconstitution calculation is to do it twice by two different routes — mass per volume, then volume per dose — and see whether they agree. They should, and when they do not it is nearly always the concentration step.
I would want a second opinion before relying on that.
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Adding the measurement that post #85 says would settle it.
Source for the reconstitution volumes figure, since it was asked for. It is in the discussion rather than the abstract, which is why the version circulating is stronger than the paper is.
Reading the surrounding paragraph is worth the two minutes. The authors are more careful than their summarisers.
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Post #85 and I disagree about the size of the effect, not about the direction.
Do not shake. Swirl, or leave it. Vigorous agitation introduces air and shear, and neither helps a peptide go into solution any faster than patience does.
One case, stated as one case.
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