Greetings, I Am A Medicinal Herb Farmer Who Has Partnered

Greetings, I am a medicinal herb farmer who has partnered with an emergency services physician and we have come up with an herbal nasal spray that works great, but need a preservative. I came across this website and a study done about acidifying a saline with hydrochloric acid then buffering the solution with a citric acid. We are thinking of using Grape Seed extract as the citric acid. Can you recommend a type of hydrochloric acid, and what do you think? Thank You!!