If I buy duac, do not open it, and refrigerate it. How long will it last in the fridge? I know it expires after 60 days once it is dispensed. I just want to know if so if I buy more than one, the unopened tubes won t go bad. Also, if it does last longer, Will it be affected at all if not refrigerated for 4 or 5 days while being delivered in the mail. Thank You