Comparative study of structural and compositional changes of polycomplex matrices based on Eudragit® EPO and Eudragit® L100.

New interpolyelectrolyte complexes (IPECs) between oppositely charged types of Eudragit EPO and Eudragit L100 were synthesized at pH 6.0, 6.5, and 7.0 with a view to their application in oral controlled drug delivery systems. Differences among the obtained IPECs were evaluated by FTIR spectroscopy and elemental analy- sis. The results confirm that the polycomplexes are stabilized by intermacromolecular ionic bonds and have compositions Z = 1.02, 1.49, and 2, respectively. Monitoring of microenvironmental changes in the polycomplex matrices during swelling in model gastrointestinal fluids indicates that all IPECs can be considered as potential pH-sensitive carriers due to structural and compositional transformations. The established properties of the synthesized IPECs suggest that they have high potential to be used as pH-dependent oral drug delivery systems. [ABSTRACT FROM AUTHOR]