with mine, (before the liquid ban) I put it in an insulated lunch bag with an ice pack. I also needed to have a letter from the doctor since mine was injected with a needle.
Small soft side cooler or insulated lunch bag with one of those small blue ice things. I think they allow regular ice as well for medications, but the blue packs are less of a problem.
Some people like Frio paks - a search on google on something like FRIO INSULIN will pull up places that sell them. They are packs that are water activated and reusable - no fridge required.