Morning,
I have used ones that were made into a spray as it was advertised as quicker effects, worked as well as injection, but did not make it myself. I was using a peptide company out of the UK who had a store in the US. I tried many and not one could hold a candle to injections.
Your supposed to spray this water like substance and it try not to have it 'just run down your throat into your stomach;. I tried approximately 5 and not one worked near as well as an insulin injection.
I am not really answering your question, but this peptide company was one of the best I dealt with and their products worked well. Unfortunately, this nasal spray system of administration sucked. You had to take a massive amounts of sprays in order to get to the desired dosage as well.
If I mixed anything with sterile water, I would not expect it to keep for too long as it does not inhibit bacterial growth at all. Even with HGH that comes with sterile water, most have inserts that indicate take all at once. Ex: Sero - comes with sterile water and the instructions indicate to use the vial all at once if my memory serves me correct.