thanks guys , some info from
http://www.drugs.com/humalog.html
Vials and cartridges of Humalog can be kept unrefrigerated for up to 28 days, but should not be exposed to excessive heat or sunlight
Once punctured, the insulin vial or cartridge in use, whether stored in the refrigerator or at room temperature, must be used within 28 days. Throw away any unused insulin 28 days after the vial or cartridge is first punctured