I'm trying to prepare a gliadin solution that has the protein concentration of 20 mg/ml and want to dissolve it in 70% ethanol. However, since I want to use this gliadin solution as allergen in animal study, I need to make it suitable for injections and for that I need to adjust pH to 7 and when I try to do that, I add PBS but then the solubility of gliadin and the protein concentration I want to have decreases each time I add PBS. So, in the end, I never really have 20 mg/ml of concentration that is required for my project. However, if I increase the concentration, then I would also reach the solubility limit that I can solve with 70% ethanol or how can I really know the solubility limit of this solution? If there is anyone who has any advice on the issue, I would really appreciate it.

Thank you :)