Narrowing post #7, because the general version has more than one answer. Adding what did not work for me on published stability data actually covers, since the failures never get written up and they are half the useful information.
The question in the title: What published stability data actually covers, and what it does not I will give what I have already checked below so nobody repeats it.
Reading back through what has been written here about published stability data actually covers, three questions come up every time and only one has ever been answered properly.
Listing all three, with what I think the state of the answer is for each, so the thread can start further along than the last one did.
Two sentences on published stability data actually covers 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.
Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear.
Not the answer, but possibly the question that gets there.
The arithmetic in post #3 is right; the assumption feeding it is the part to check.
Published stability data actually covers: I would want to see the raw numbers rather than the summary before agreeing. Summaries lose exactly the information that would settle this.
Published stability data applies specifically to the formulation studied, under the specific conditions stated. It does not automatically transfer to something reconstituted at home in a different concentration with a different diluent. That caveat is not small.
It is worth stating the boring hypothesis before the interesting one.
Everything in post #3 holds. The case it does not cover is the one I have.
The claim about published stability data actually covers upthread is stronger than its source supports. I have read the source. The source says "associated with" and the post says "causes".
Narrowing post #7, because the general version has more than one answer.
Adding what did not work for me on published stability data actually covers, since the failures never get written up and they are half the useful information.
A supplier stability statement tied to a named storage condition can be evaluated. One that says "store cool" cannot, and the difference between those two documents is larger than it looks.
This has been discussed before and I could not find the thread, so, again.
Acknowledging rather than arguing. The reasoning holds as far as I can follow it.
The question underneath published stability data actually covers is usually "how would I tell?" rather than "what is true?", and that one has a method attached to it.
Write down what you would expect to see under each hypothesis before you collect anything. If they predict the same observation, collecting it will not help.
Seconded. It reads as careful rather than confident, which is the right register.
I read post #11 twice before replying, because I had assumed the opposite.
Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed.
Adding the caveat now so it does not have to be extracted later.
Nobody has said the unglamorous part of published stability data actually covers yet, so: most of the variation is explained by things that are boring to write about and easy to check.
My experience of published stability data actually covers contradicts the reply above. I am posting it as a data point rather than as a refutation, because one person's experience is exactly that.
Published stability data covers a specific formulation at a specific concentration in a specific container. A home-reconstituted preparation matches none of those, and that caveat is the whole of the honest answer.
Coming back to post #14, because the follow-up matters more than the original answer.
Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear.
Saving this. It is the version I will quote when the question comes round again.
Right — I had this wrong and I am glad to have read it before it mattered.
Checked the published stability data actually covers claim against the primary source this morning. It survives, with a narrower scope than the version quoted here. Posting the narrower scope.
I want to gently push back on the reply above about storage extrapolation. The advice is sound and the confidence is not.
We are extrapolating from stability data on a licensed formulation to a preparation that differs in concentration, diluent and container. That extrapolation is reasonable and it is still an extrapolation. Saying so does not weaken the practical recommendation; it just stops the recommendation from hardening into a fact that someone cites as certain.
On published stability data actually covers I would separate what is worth knowing from what is worth acting on. The first list is long and the second is short, and conflating them is how threads get heated.
I had written a reply contradicting post #24 and deleted it. Here is what survived.
Counterpoint on published stability data actually covers, offered without confidence: the same observation is consistent with a much duller explanation, and nobody has ruled the dull one out.
Visible particulate is a strong signal in the other direction: it is a reason to stop and ask rather than to filter and proceed.
Answering the question post #27 raises rather than the one it answers.
Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear.
Offering a way to settle published stability data actually covers rather than another opinion about it. Two measurements, taken the same way, a fortnight apart. If the difference is within the noise, the question was not answerable at this precision.