Multi-stimuli responsive nanogel/hydrogel nanocomposites based on κ-carrageenan for prolonged release of levodopa as model drug.

This study describes the development of a novel biocompatible nanogel/hydrogel nanocomposite system for long-term delivery of bioactive molecules. To this aim, the nanogels were synthesized via radical polymerization of poly(N-isopropylacrylamide). The nanogels were introduced during the formation of a hydrogel network to produce nanogel/hydrogel soft nanocomposites, while the biocompatible hydrogel was based on poly (acrylic acid) grafted onto κ-carrageenan polysaccharide with entrapped magnetic iron oxide nanoparticles as crosslinker. In these systems, by using stimuli-responsive functional polymers in both gels (nanogels and hydrogels), pH, thermal and magnetic-responsive properties can be brought to final soft nanocomposites. The obtained soft nanocomposite was characterized by Fourier transform infrared spectrum (FT-IR), thermogravimetric (TG) analysis, and scanning electron microscopy (SEM). This biopolymer based nanogel/hydrogel used as a prolonged releasing drug carrier for levodopa (L-DOPA) as a main drug for treating Parkinson's symptoms. The in vitro release of L-DOPA was investigated at different pHs. pH-dependent release of the active drug can be sustained for >11 days from this soft nanocomposite. The results demonstrated a sustained release model that can be extended for other drugs.