Good question, well framed, and I would like to see it answered properly.
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Practice · Storage & stability · continued
Storing lyophilised material long term: what governs the shelf life posts 31–60
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
h.nicolaides, post #27: Reframing storing lyophilised material long term slightly, because I think the disagreement is about the question rather than the answer. If the question is "does it happen", yes. If it is "how often", nobody here knows. Go to post
Taking post #29 at face value and following it one step further.
The two questions that get merged here are whether material is degraded and whether it is contaminated. Storage affects both and they need different answers and different tests.
If you are going to test stored material, test it against a sample of the same lot stored properly rather than against the certificate. Otherwise you are measuring the difference between two laboratories as well.
I am not the right person to answer the follow-up to this.
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Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed.
That is the version I use. It may not be the version that is correct.
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Post #33 put the caveat in the right place and I want to underline it.
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.
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v.bhattacharya, post #34: Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed. That is the version I use. It may not be the version that is correct. Go to post
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.
The arithmetic in post #37 is right; the assumption feeding it is the part to check.
For anyone finding this later: the short answer on storing lyophilised material long term is that it depends on one thing, and the rest of the thread is people identifying which thing.
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Before the thread moves on from storing lyophilised material long term — 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.
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Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed.
Marking that as an opinion rather than a finding.
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Adding the measurement that post #38 says would settle it.
Adding a reference point for storing lyophilised material long term. Mine is a single case, collected without controls, and I am posting the method alongside it so it can be discounted appropriately.
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Post #40 describes the usual case. This is about the unusual one.
The failure mode on storing lyophilised material long term is boring rather than dramatic. It is almost always the step everyone assumes was done correctly because it is too simple to get wrong.
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l.vermeulen, post #41: Adding the measurement that post #38 says would settle it. Adding a reference point for storing lyophilised material long term. Mine is a single case, collected without controls, and I am posting the method alongside it so it can be discounted appropriately. Go to post
I would call the community position on storing lyophilised material long term likely rather than established, and I would be comfortable defending that hedge.
Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed.
Two sources, same conclusion, and I could not rule out that one copied the other.
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Answering the question post #44 raises rather than the one it answers.
Genuine question rather than a rhetorical one: has anyone here actually observed storing lyophilised material long term, as opposed to read about it? The thread is long and I cannot tell.
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That is clearer than the version I had in my head. Thank you.
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n.villalobos, post #39: Before the thread moves on from storing lyophilised material long term — 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
Storing lyophilised material long term is a question about a distribution, not about a value, and treating it as a value is what produces the confident wrong answers.
Dry storage in a freezer is generally more protective than a refrigerator for long periods, provided the material is genuinely dry and the container genuinely sealed. Condensation on removal is the trap.
Adding this to the thread rather than to the wiki, because I am not confident enough for the wiki.
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This follows post #50 rather than contradicting it.
The useful distinction on storing lyophilised material long term 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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Reconstituted material carried in a bag for a day is a temperature excursion even in a cool climate. Where that matters is cumulative exposure over weeks rather than a single afternoon.
Worth saying I have only my own numbers here, and n is small.
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a.kowalski, post #31: Good question, well framed, and I would like to see it answered properly. Go to post
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.
I would want the raw data before agreeing with my own summary of it.
On post #52 — agreed on the reasoning, with one qualification.
Two claims get bundled together under storing lyophilised material long term and they need separating. The descriptive one — this is what was observed — is usually well supported. The causal one — this is why — usually is not.
Almost every disagreement in threads like this one dissolves once you say which of the two you are making.
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On storing lyophilised material long term, the part that usually goes wrong is that the question is asked as though it has one answer. It has a range, and the width of the range is the interesting bit.
If you can post the two or three numbers you are working from, several people here will check the arithmetic rather than argue about the conclusion.
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n.villalobos, post #39: Before the thread moves on from storing lyophilised material long term — 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
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.
v.szabo, post #9: Reconstituted material carried in a bag for a day is a temperature excursion even in a cool climate. Where that matters is cumulative exposure over weeks rather than a single afternoon. Go to post
Two things can be true about storing lyophilised material long term at once: the mechanism is plausible and the evidence for the size of the effect is thin. Most of the argument here is people defending the first against attacks on the second.
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.
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