If you are using 1vial/day, sterile water for injection is enough.
if you wanna keep vials in fridge and use it for more than 1 day, you need to mix it with bacteriostatic water.
Ozempic and all pharmaceutical injectable solutions like hgh, insulin.. contains many excipients such Disodium phosphate dihydrate Propylene glycol Phenol Hydrochloric acid (for pH adjustment) Sodium hydroxide (for pH adjustment) + Water for injections.
You don't need all that, bacteriostatic water is enough.
why are there oral tablets that are semaglutide and have to be taken daily?
It's is recommended to take most of products daily to have stable levels, I don't know if it's related to half life in this case, but I know that some products half life can change for oral vs injectable such as winstrol : oral winstrol half life is few hours, injectable is 48 hours, that's why it can be take every other day.