I agree with Annette – insulin should be fine in relatively normal temperatures. I take the view – whether rightly or wrongly – that insulin is a protein, like eggs. So if it’s hot enough to cook an egg it’s hot enough to cook insulin. This might be entirely rubbish – perhaps more scientific (or, indeed, scientific!) readers can set me straight.
Failing that, these chaps works quite well – http://www.friouk.com/ – in keeping things cool without the use of a cold, cold fridge.