I left a bottle of peptides on my desk without refrigeration for about 24 hours. Are the peptides ruined? My house is generally kept cool and the bottle was cool to the touch when I picked it up again. Can I still use this bottle?
As I've said in the comments it depends on the specific product, so I can't really give a straight yes or no answer. But I'll give a few examples, and I hope that will help.
Peptides that are already in a liquid form (as a suspension or a solution) are meant to be refrigerated between 2 and 8 degrees Celsius (i.e. 35 and 46 degrees Fahrenheit). They must not be frozen or they will lose their activity (it is not your question, but while we're at it this might be different for powders).
Most of these formulations can be kept at room temperature for a certain amount of time (usually 2-4 weeks), but they must be protected from sunlight.
Here are some examples:
NovoRapid - insulin aspartat solution (SmPC section 6):
During use or when carried as a spare: The product must be stored for a maximum of 4 weeks. Store below 30°C.
Before opening: Store in a refrigerator (2°C - 8°C). Do not freeze.
Insulatard - human insulin suspension (SmPC section 6):
During use or when carried as a spare: The product can be stored for a maximum of 4 weeks. Store below 25°C.
Before opening:Store in a refrigerator (2°C – 8°C). Do not freeze.
Rebif - interferon beta solution (SmPC section 6):
Store in a refrigerator (2°C – 8°C) away from the cooling element. Do not freeze. Store the cartridge in the original package in order to protect from light.
The device (RebiSmart or RebiSlide) containing a pre-filled cartridge of Rebif must be stored in the device storage box in a refrigerator (2°C – 8°C).
For the purpose of ambulatory use, the patient may remove Rebif from the refrigerator and store it not above 25°C for one single period of up to 14 days. Rebif must then be returned to the refrigerator and used before the expiry date.
Keep the NordiPen 5 (with the Norditropin cartridge 5 mg/1.5 mL inside) EITHER refrigerated (2-8°C/36-46°F) for 4 weeks OR store not above 25°C (77°F) for 3 weeks. Do not freeze.
BUT I also found an example where prolonged storage outside of the refrigerator is not mentioned, also for a somatotropin product:
After the first use the cartridge should remain in the pen and has to be kept in a refrigerator at 2° to 8°C (36° to 46°F) for a maximum of 28 days (see Table 11).
To sum it up, the reliable source for proper storage of a pharmaceutical product is the manufacturer. They are the ones who tested the stability under various storage conditions and had to share these information with the regulatory body - which is a second reliable source for this type of information. You should be able to obtain the patient information leaflet from your heath care provider (e.g. a pharmacist) or from the internet for a specific product. Or you should be able to obtain the Summary of Product Characteristics from the regulatory body (FDA, EMeA or a national medicines agency) by contacting them or from their website. Ultimately you can contact the manufacturer's representative office and inquire about proper storage conditions and shelf-life for a specific product in question.