Enhancing the Acidity of Polymers for Improved Stabilization of Amorphous Solid Dispersions: Protonation of Weakly Basic Compounds

A cross-linked poly(vinylphosphonic acid) (PVPA) stabilizes compounds in amorphous solid dispersions (ASDs). The performance of the polymer was compared to that of hydroxypropyl methylcellulose acetate succinate (HPMCAS), a polymer commonly used in commercial ASDs. Model compound loading demonstrates the stronger protonation ability and greater amorphous loading of compounds with varying basicity by cross-linked PVPA than HPMCAS. These results highlight the potential for polymers with high concentrations of acid functionality to enable increased physical stability and loading in ASDs that are not readily achieved with existing polymers.