The opening post describes the usual case. This is about the unusual one. 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.
Swirling versus inverting versus leaving it alone Writing it up because I had to work it out twice and would rather nobody else did.
Swirling versus inverting versus leaving — I have the observation and I do not trust my interpretation of it, so I am posting the observation and holding the interpretation back.
Numbers, method and the conditions under which they were collected are below. Interpret them however they warrant.
Bookmarking this. I will come back when I have something worth adding.
Swirling versus inverting versus leaving looks different depending on whether you are reading the primary literature or the summaries of it, and the difference is not in our favour.
Summarising the Swirling versus inverting versus leaving thread so far, since it is long and the answer is buried: the first reply has the method, the fourth has the correction to it, and the rest is people agreeing at length.
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 have kept the units in throughout, for the obvious reason.
Answering the question post #5 raises rather than the one it answers.
Swirling until fully clear before drawing is worth the extra minute. A partially dissolved preparation is not uniform and the first dose out of it is not the same as the last.
Small point, but it is the one that usually catches people.
The arithmetic in post #5 is right; the assumption feeding it is the part to check.
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.
Same experience here, different supplier, so it is at least not unique to one of them.
Building on post #8 rather than restating 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.
Fair, and the limits you put on it are the part I will remember.
A definition problem is doing most of the work in this Swirling versus inverting versus leaving discussion. Once the term is pinned down I suspect the disagreement mostly goes away and what is left is small.
Post #14 is right about the mechanism and I think understates the practical bit.
Swirling versus inverting versus leaving it alone: the vial can be gently warmed (hands around it) and swirled with a rolling motion. Vigorous shaking introduces air and can denature the peptide. Leaving it alone at room temperature usually works given enough time.
This settles it for me, at least until somebody posts a reason it should not.
Building on post #18 rather than restating 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.
Adding what did not work for me on Swirling versus inverting versus leaving, since the failures never get written up and they are half the useful information.
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.
Post #21 and I disagree about the size of the effect, not about the direction.
A cake that takes a few minutes to dissolve is ordinary. A cake that will not dissolve after gentle swirling and standing at room temperature is worth raising with the supplier rather than working around.
Taking post #21 at face value and following it one step further.
Swirling versus inverting versus leaving has a well-known answer and a correct answer, and the interesting work is establishing that they are the same. Nobody has done that here yet.
My understanding of Swirling versus inverting versus leaving 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.
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