Practice · Storage & stability

Light exposure: how much protection is proportionate?

Practice › Storage & stability beyond-use date freeze-thaw cold chain cloudy or discoloured solution storage

r.erdoganTL221 Mar 2026#1

The question in the title: Light exposure: how much protection is proportionate? I will give what I have already checked below so nobody repeats it.

Trying to establish the boundary conditions on light exposure. The general claim is fine; I want to know where it stops holding, because that is where I am operating.

Three edge cases below, in increasing order of how far outside the usual range they sit.

10 likes 4mo

s.solbergTL28 Apr 2026#2

The arithmetic in the opening post is right; the assumption feeding it is the part to check.

Light protection is easy and cheap. The original carton exists for a reason and a vial stored in it is protected without anybody having to think about it again.

0 likes 4mo

v.klausenTL3Regular21 Apr 2026#3

Where I part company with the opening post, and it is a narrow parting.

Refrigeration slows degradation. Repeated warming and cooling is worse than continuous refrigeration. Light exposure is worth avoiding. The concentration matters because adsorptive losses are proportionally larger in dilute solutions. All of that is reasonably well supported.

Scoping that to what I have actually seen rather than what I have read.

0 likes 3mo

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