Expiration dates on Maracyn & Maracyn 2

I want to order some of both to keep around in case they are needed since Im in a rural area with no fish stores, Walmart or anywhere else I could get something to treat my fish with. Could someone tell me how long they are good for? Im assuming both will have expiration dates and depending on how long they keep is what size I will order.
Thanks!

I wonder too. I know that antibiotics used for humans as wells as cats and dogs have an expiration date, and after that date will start to lose potency, Im assuming the same thing applies to aquarium antibiotics. But if you start with a low grade product, it will deteriorate much quicker, so who knows.