Molecular mobility of PSA, along with the strength of drug-PSA interaction was evaluated by thermal analysis and dielectric spectroscopy.  It turned out that instead of PSA molecular mobility, molecular interaction between ion-pair and PSA played a dominant role in the controlled release process of BSP: as illustrated by FTIR, Raman and molecular docking, the ionic interaction between BSP-C12 and PSA determined the amount of BSP released, namely the thermodynamic process; while the doubly ionic hydrogen bond between BSP-C12 and PSA-COO- controlled the release rate, which was the kinetic process. 
THERM