[Retric]

The general rule is increasing temperature by 10C roughly doubles the rate of chemical reactions. https://www.ddltesting.com/package-testing/shelf-life-testin...

Though in practice it’s more complicated. Basically, make predictions based on accelerated testing and then validate them in real time tests. So, if things hold up at 3 and 6 months real time you can probably trust them over longer timeframes.

[refurb]

Exactly. Plus dating tends to get extended post-approval.

If Pfizer has a short-list of candidates back in May, they could have had 6 months of stability data at approval.

They can keep those studies going and by next May have 12 months of data for the FDA to review and potentially update the transportation and storage requirements.

[maxerickson]

In practice it seems the expiration dates on even boring drugs aren't real far into the future.

[Retric]

Yea, prescription drug manufacturers have little incentives to seek multi year shelf lives. Combined with the slow approval process real time testing is likely considered sufficient.

https://www.pharmacytimes.com/news/some-medications-last-lon...

[rainbowzootsuit]

There's a US government program that tests drugs' efficacy beyond the manufacturer dating to extend the life of the stockpiles.

https://www.astho.org/Programs/Preparedness/Public-Health-Em...

[refurb]

I think you summarized it well. There is little incentive to test the limits of stability as manufacturers typically control channel inventory quite tightly. I know my company targeted maybe 14 days on hand? So going much beyond 2 years stability didn’t make much sense as most product was consumed well before it expired.