I am trying to create an aqueous phospholipid suspension using ~50 mg of 1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC), 13 mL of propylene glycol (PG), and 72 mL of phosphate-buffered saline (PBS). I am easily able to get the DBPC to dissolve in the PG when held at 85 degrees (10 above Tm), but as soon as I add any sizable amount of PBS, my solution turns cloudy with chunks of DBPC floating around, implying that the DBPC has precipitated out and aggregated.
Why would this be? I'm basing myself off of this patent, and they do mention that trying to dissolve the lipid directly in water causes aggregation, but why would adding PBS to my already dissolved lipid do this?
Structural photos below: