0.2 or 0.22 um for sterilization, you should be able to find them on amazon or other web stores. They'll fit onto the big 30ml+ syringes for filtering an entire nasal sprat bottle at once
Okay and would 0.2 Micro filter be better though? I'm also wondering how do I find out the best ratio of medication to liquid solution I guess I'd like to start with cocaine since that should theoretically be easiest drug to make a nasal spray solution out of lol. Next I'd like to try an opioid and or benzo if possible too. I'm thinking maybe hydromorphone or Oxymorphone nasal spray and a midazolam nasal spray solution.