Useful. I had the fact and not the reason, which turns out to be the important half.
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Practice · Reconstitution · continued
Reconstituting a multi-strength kit without mixing yourself up posts 31–60
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
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.
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h.varga, post #21: 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. This is the sort of thing that ought to be settled and apparently is not. Go to post
Post #30 put the caveat in the right place and I want to underline it.
Practical experience of reconstituting a multi-strength kit, offered as one case with the conditions stated, not as a general finding. Conditions first, because they are what make it interpretable.
a.salcedo, post #18: Reconstituting the whole vial when you will use a quarter of it is a decision to store the rest in solution, which is the least stable state it will ever be in. Sometimes that is the right trade and it should be a decision. Go to post
Taking post #36 at face value and following it one step further.
My understanding of reconstituting a multi-strength kit is a few years old and may have been superseded. If it has been, I would genuinely like to know rather than keep repeating it.
a.ilunga, post #27: Saving this. It is the version I will quote when the question comes round again. Go to post
Post #34 and I disagree about the size of the effect, not about the direction.
How much of the diluent volume the powder itself displaces: for a small peptide vial, the powder volume is negligible. For a larger vial or a kit with multiple compounds, the displacement can be a few tenths of a millilitre. If precision matters to you, account for it by targeting a final weight rather than a final volume.
That is the version I use. It may not be the version that is correct.
GSwinburne, post #2: 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. Go to post
The arithmetic in post #36 is right; the assumption feeding it is the part to check.
Adding what did not work for me on reconstituting a multi-strength kit, since the failures never get written up and they are half the useful information.
On post #39 — agreed on the reasoning, with one qualification.
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 literature is thinner on this than the confidence in the thread implies.
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appeals_desk, post #37: Taking post #36 at face value and following it one step further. My understanding of reconstituting a multi-strength kit is a few years old and may have been superseded. If it has been, I would genuinely like to know rather than keep repeating it. Go to post
I disagree with the framing of reconstituting a multi-strength kit above, and I think it is a substantive disagreement rather than a terminological one. Setting out why, so it can be checked.
The reasoning depends on an assumption that is doing a lot of work and is never stated. If the assumption holds, the conclusion follows. I do not think it holds generally.
Collapsed as off-topic by two members at trust level 3 or above
Post #43 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.
I would rather be precise about what I do not know than vague about what I do.
This follows post #43 rather than contradicting it.
Speaking only to reconstituting a multi-strength kit as I have actually seen it, rather than as it is usually described: the effect is real, it is smaller than the thread suggests, and the variance between people is larger than the effect.
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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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a.finnegan_rd, post #26: The confident answers on reconstituting a multi-strength kit and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category. Go to post
I came in to disagree and I am leaving without a disagreement.
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.
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v.kirchner, post #23: Where I part company with post #21, and it is a narrow parting. Before the thread moves on from reconstituting a multi-strength kit — what is the sample size behind the claim? I am not being difficult; I have seen the same figure quoted from an n of four and from an n of four hundred. Go to post
Post #50 answers the question as asked. The question underneath it is different.
Two questions I would want answered before drawing anything from the reconstituting a multi-strength kit data above: how were the cases selected, and what happened to the ones that dropped out.
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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.
It is a small point and it changes the answer, which is an awkward combination.
This is the sort of exchange that makes the archive worth searching.
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Worth separating two things that post #51 runs together.
Reconstituting the whole vial when you will use a quarter of it is a decision to store the rest in solution, which is the least stable state it will ever be in. Sometimes that is the right trade and it should be a decision.
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ar.kravchenko, post #19: Confirming post #18 from a second method, which matters more than confirming it from a second person. I keep a log for reconstituting a multi-strength kit specifically because my memory of it turned out to be systematically wrong in one direction. Six weeks of notes cost nothing and settled it. Go to post
Post #54 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.
Coming back to post #54, because the follow-up matters more than the original answer.
Posting my reconstituting a multi-strength kit numbers with the method attached so they can be discounted properly. Uncontrolled, unblinded, and collected by someone who wanted a particular answer.
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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
An honest declaration on reconstituting a multi-strength kit: I have a prior here and it is strong enough that you should weight what I say downward. Stating it rather than hiding it.
I had written a reply contradicting post #56 and deleted it. Here is what survived.
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.
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