Study on the properties of a polymer system based on poly (ethylene glycol), n-isopropyl acrylamide and chitosan for controlled drug delivery

Structured hydrogels with thermo-sensitivity properties to be used as a novel carrier for controlled drug delivery were prepared here. These hydrogels were formed by core-shell particles, where the core is a semi-interpenetrated polymer network (semi-IPN) made of n-isopropylacrylamide (NIPAAm) and poly (ethylene glycol) (PEG), and a chitosan shell. All polymers were synthesized by using semi-continuous heterophase polymerization at different dosing rates to study their effect on particle size, system stability and drug deliver efficiency. Structural (FTIR, particle size, SEM) and functional analysis were performed (stability and drug delivery). FTIR confirmed the polymerization by showing the development of interactions between the characteristic functional groups from the polymers. SEM micrographs from hydrogels revealed a porous structure, which is affected by the dosing rate during the polymerization process as well as the particle size which affect the stability of the obtained latex. Drug release analysis of the hydrogels was performed into distilled water and in a buffer at different temperatures. Results shown that most of the characteristics of this polymer system can be controlled, and so tuning the controlled release behaviour, these findings made these hydrogels an important contender for controlled drug delivery.