Solubility of epinephrine in water
What the context of aiming for a highly concentrated aqueous solution of epinephrine / adrenaline?  What would be a sufficient concentration?  Would -- assuming a chemical reaction is intended -- in sight of a low reaction rate a steady of epinephrine in low concentration be sufficient?

While this lists a typical concentration of saturation in water of about 180 mg/L, other conditions are provided, too.  The list equally includes a statement like "soluble in acetic acid" -- so perhaps you do not need to decrease the pH value down to 1 (by HCl), and maybe you were able to obtain a sufficient concentration of epinephrine in a mixture of water / acetic acid, too?

Are there restrictions, imposed by the intended application / compatibility  toward (biological?) materials to stay near neutral conditions?  One way to reply to this and to tailor solubility of pharmaceutical active ingredients is to refrain from their form as free acids or bases, and to use them as salt.  In this sight, would be epinephrine tartrate, or an acetate, an alternative option?