Synthesis, characterization and swelling behavior of new pH-sensitive hydrogels derived from copolymers of 2- hydroxyethyl methacrylate and 2-(diisopropylamino) ethylmethacrylate.

PAULA A. FACCIA, JAVIER I. AMALVY

JOURNAL OF APPLIED POLYMER SCIENCE

JOHN WILEY & SONS INC

Lugar: New York; Año: 2012

0021-8995

The aim of this work was to synthesize and to characterize new pH -sensitive hydrogels that can be used in the controlled release of drugs,useful for dermal treatments or ophthalmology’s therapies. Copolymerscontaining 2-hydroxyethyl methacrylate (HEMA) with different amounts of2-(diisopropylamino)ethyl methacrylate (DPA) (10 and 30 wt. %) anddifferent amounts of cross-linker agent , ethylene glycol dimethacrylate(EGDMA) (1 and 3 wt. %) were prepared by bulk photo-polymerization.The copolymers were fully characterized by using FT-IR, DSC, TGA, UVvisiblespectroscopy, and measuring water content and dynamic swellingdegree. The results show that modifications in the amount of DPA and/orcross-linker in the hydrogel produce variations in the thermal properties.When adding of DPA, we observed an increase in the thermal stability anddecomposition temperature, as well as a change in the mechanism ofdecomposition. Also a decrease in the glass transition temperature wasobserved with regard to the value for pure pHEMA, by the addition of DPA.The water content of the hydrogels depends on the DPA content and it isinversely proportional to both the pH value and the cross-linking degree.Pure polyHEMA films did not show important changes over the pH rangestudied in this work. The dynamic swelling curves show the overshootingeffect associated with the incorporation of DPA, the pH of the solution andthe cross-linking density. On the other hand, no important variations in theoptical properties were observed. The synthesized hydrogels are useful asa drug delivery pH-sensitive matrix.