Would you re-test orforglipron after eight weeks at 37 °C, or accept the original certificate?

What I am working with: orforglipron · eight weeks · 37 °C.

I would like to set this up properly once, rather than adjust it repeatedly.

My budget is real but not tight, and my tolerance for uncertainty is low.

What would you do, and what would make you change course?

eight weeks is 56 days, and at 37 °C the ten-degree rule of thumb makes that roughly 515 refrigerated days of equivalent exposure. 37 °C is 32 kelvin above the 5 °C middle of a 2–8 °C refrigerator. The ten-degree rule of thumb — degradation rate roughly doubling per 10 K — makes that about 9.2 times the refrigerated rate, which is an order-of-magnitude statement and not a shelf life. Compare that against what the certificate covers, which is the material as it left the laboratory on the date of analysis and nothing after it. 515 equivalent days is past the point where the original figure is evidence about the current vial, so the honest answer is that you no longer have a certificate for what you are holding. If you do re-test, send it for content as well as purity; the 56 days will have moved one of them further than the other.

Start from the question: how many vials from this lot do I need to test to claim that the lot meets specification, and the answer depends on both the lot size and the acceptable risk.

Under AQL sampling plans, testing two vials from a fifty-vial lot gives you an operating characteristic curve that tells you what risks you are accepting.

Mass shifts and what they usually mean

It helps to be literal here: if you have reason to suspect inhomogeneity — different appearance in different vials, or a long or warm shipment — testing more vials is the diagnostic move.

The limitation is that you cannot know for certain without testing every vial, and you almost never can afford to do that.

If testing multiple vials, state how many you tested and why you chose those vials.

edited 6 Mar 2026 by Dr_Otto_Lindqvist — expanded the table to cover the lower concentration

A certificate that reports one test result on one vial extrapolates to claim that all two hundred vials in the lot are identical, which is an assumption worth questioning.

Acceptance Sampling by Attributes defines the number of samples you need from a lot to claim a specified quality level at a specified risk — it is in ANSI standard Z1.4.

Stratified sampling — testing one vial from the top, one from the middle, and one from the bottom of a shipment — is cheap insurance against segregation.

I would treat a "complies with" statement without sampling details as a claim rather than as evidence.

The practical summary: a lot number without a sampling statement is a lot number without meaning.

In practice, if a lot has visibly segregated — some vials showing different appearance — then sampling the top and bottom of the shipment is worth doing.

If the entire lot failed qualification, a retest on a different vial is sometimes done, but reporting a retest result under the same lot number is misleading.

The underlying point is that a statement that "lot 20260412 complies with specifications" is meaningless without stating which vials from the lot were tested and how many there were.

Published data on lot homogeneity from manufacturers who sample multiple vials consistently find variation below the published specifications, suggesting the sampling plans work.

One qualification: testing more vials gives better confidence, but at some point the cost outweighs the benefit.

Assume segregation is possible, and design your sampling to catch it if it exists.