Well - a one-person test would be easy - prepare prop using the standard formulation and the idea I had - try them on the same person, and see what happens.
I may do just that, as I am currently experiencing prop pain myself - Homebrewed, but I'm a chemist, I know a thing or two about sterile solution preparation.
I would be worth trying - this 2-3 days of discomfort in major muscle groups is for the birds.
The only other idea I could think of was adding something to take the propionic acid out of the equation by having a mildly alkaline agent in the mix which could maintain the pH of the injection site around the physiological norm - but that gets complicated.
By the way, is it just me that can't get past the main sub-forum header? I had to jump in here by linking to a recent post.....
Doctor9