Polymethacrylate salts as new low-swellable mucoadhesive materials

The sodium and potassium salts of the methacrylic copolymers Eudragit ® L100 and Eudragit ® S100 were prepared with the aim to develop new low-swellable mucoadhesive materials intended for the preparation of buccal dosage forms. The physico–chemical characterization of the copolymers and the corresponding sodium and potassium salts was performed by using Fourier-transform infrared (FT-IR) spectroscopy and thermal analysis. When ionization occurred, the carboxylic acid group absorption band (1730 cm −1) was replaced by another characteristic band at 1560 cm −1. After salification the T g of the two polymers shifted towards higher values and it was not significantly influenced by the contraion nature. The intrinsic dissolution rate at infinite rotation speed (7.354< G ∞