Why are there some medicines that are put in the fridge?
Thanks
Chemical reactions are slowed down at lower temperatures; refrigeration can increase the shelf-life of medicines that would not last long enough at room temperature.
Refrigeration could be important for the active ingredient or for the formulation as a whole.
Note that refrigeration can also be a problem for some formulations, so it's important to follow storage instructions.
The effects of short-term failure to refrigerate drugs that are supposed to be refrigerated varies, see Cohen et al. 2007 for a compilation of manufacturer instructions for a variety of drugs.
References
Cohen, V., Jellinek, S. P., Teperikidis, L., Berkovits, E., & Goldman, W. M. (2007). Room-temperature storage of medications labeled for refrigeration. American Journal of Health-System Pharmacy, 64(16), 1711-1715.