Is it safe for insulin to be dispatched by post?

Is it safe for Caninsulin to be dispatched by post, particularly regarding cold storage?

As a precaution, we post out insulin in a cold pack, which should keep the product cool for a period of 3 days. However, the fact is that Caninsulin (along with other forms of insulin) is not as temperature sensitive as many people believe. If you read the data sheet from the manufacturer which accompanies the product, you will see that they are confident that it can be stored at room temperature for 28 days. Long-term storage is advised to be at fridge temperature, but they are happy once the product is in use, for it not to be fridged at all. (This has some benefits for patient comfort - the insulin is not cold when injected. Some human hospitals apparently do not fridge their supplies once they are in use. It is important to discard any remaining product once the vial has been broached for 28 days. This is mostly due to potential contamination concerns in fact.)

Other theoretical concerns for insulin being sent by post are prolonged contact with the rubber stopper in the top of the vial, and repeated shaking. Both of these things can cause some degradation of the insulin and reduction of efficacy. However these concerns have been evaluated by various manufacturers and large scale users of insulin, and the degree of degradation in normal circumstances is insignificant. We are confident that Caninsulin can safely be sent by post.