There's really no limit to the number of times that bacteriostatic water can be frozen and re-frozen. Unlike the peptides themselves there's nothing in the water that is going to be harmed from repeated freeze cycles. That said your best game plan would be to prepare a series of syringes with the corresponding doses you'll be administering yourself and then freeze them all. Then when it comes time for a dose you simply remove one syringe, let thaw and administer the injection.  
 
-Scott