The introduction of ⿿Ouzo
diagrams⿿ has enhanced the applicability of the basic nanoprecipitation process for drug delivery research. The current study investigated the interaction of two relevant polymer/solvent systems, which is thought to impact the location of the stability⿿limit ⿿Ouzo boundary⿿.
Viscosity measurements (Kurata⿿Stockmayer⿿Fixman approach) and static light scattering (Debye method) underlined a distinct interplay of the employed polymer (poly(lactide-co-glycolide)) with the utilized organic solvents (acetone and tetrahydrofuran). Both methods indicated that tetrahydrofuran was the ⿿better⿿ solvent for poly(lactide-co-glycolide). Thus, nanoprecipitation of this polymer/solvent composition resulted in larger nanoparticles. This observation can be attributed to the chain configuration of poly(lactide-co-glycolide) in the organic solvent, which influenced the extent of the break-up of the injected solvent layer. Accordingly, the stability⿿limit curve of the ⿿Ouzo region⿿ was shifted to lower poly(lactide-co-glycolide) fractions for tetrahydrofuran.
Overall, the location of the ⿿Ouzo region⿿, which is an essential tool for drug delivery research, is influenced by the employed organic solvent. The current study described two distinct methods suitable to identify relevant polymer⿿solvent interactions, which dictate the stability⿿limit ⿿Ouzo boundary⿿ for relevant poly(lactide-co-glycolide).
