This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
Something worth flagging about Storing lyophilised material long term: the strongest-sounding claims in this thread are the ones with no source attached, which is the usual pattern and not a coincidence.
Following, with nothing to contribute beyond having asked the same thing elsewhere.
Answering the question post #90 raises rather than the one it answers.
I have three months of notes on Storing lyophilised material long term 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.
Adding what did not work for me on Storing lyophilised material long term, since the failures never get written up and they are half the useful information.
Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear.
I keep a log of this specifically because memory is unreliable about it.
Everything in post #94 holds. The case it does not cover is the one I have.
Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear.
I had written a reply contradicting post #98 and deleted it. Here is what survived.
Where the Storing lyophilised material long term discussion usually stalls is that nobody wants to say "I do not know" and everyone is willing to say "it varies". Those are the same sentence with different clothes on.
Temperature excursions: if a vial sat at room temperature for a time, the question is whether the excursion was long enough to cause damage. Hours at room temperature is usually low risk. Days to weeks raises the risk. If you are unsure, contacting the supplier is more informative than guessing.
Building on post #101 rather than restating it.
What I would want before treating Storing lyophilised material long term as settled: the method, the sample, and whether anyone tried to find the opposite result. Two of the three are usually missing.
Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed.
Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear.
Taking post #106 at face value and following it one step further.
Protecting from light: amber vials or opaque containers reduce light exposure. If you are storing for long periods and light matters, this is worth doing. For short-term prepared solutions, ordinary storage away from direct sunlight is usually adequate.
That is what I would do. It may not be what is correct.
Post #104 and I disagree about the size of the effect, not about the direction.
Answering the Storing lyophilised material long term question as asked, then the question I think is meant. As asked: yes, with the qualification below. As meant: it depends on how the first measurement was taken.
Acknowledging rather than arguing. The reasoning holds as far as I can follow it.
I have no financial interest in anything named in this thread and I want to say so before I comment on Storing lyophilised material long term, because it is the sort of subject where it matters.
Lyophilised material is far more stable than the same material in solution. That is why suppliers ship it dry, and it is the reason to reconstitute only what will be used.
Door storage in a refrigerator is the warmest and most variable position in the appliance. A shelf at the back is a materially different environment.
I think the Storing lyophilised material long term question is answerable and has not been answered, which is a more optimistic position than most of this thread.
Container choice matters: the material of the vial, the rubber closure, the fill volume all affect how quickly the contents degrade. Smaller fill volumes lose less to adsorption. Glass vials lose less to leaching than plastics.
Adding this to the thread rather than to the wiki, because I am not confident enough for the wiki.
Understood. Thank you for being specific about the limits of it.
Building on post #115 rather than restating it.
The most useful thing anyone has posted about Storing lyophilised material long term in this category was a table of what had been measured and by whom. That is what I would want again.
Worth separating two things that post #115 runs together.
Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear.
I would treat that as a working assumption and revisit it.
This follows post #119 rather than contradicting it.
Trying to state the Storing lyophilised material long term position in a way that someone who disagrees would recognise as fair, because I do not think the version in this thread passes that test.