Calcium Alginate-based Biomineralized Hybrid Materials For Smart Drug Delivery

In this thesis, a series of organic-inorganic hybrid intelligent hydrogels for smart drug release were prepared under different conditions. The structures and properties of calcium alginate biomineralized materials were characterized using IR, XRD, SEM, UV-vis etc. Results of swelling and indomethacin drug release behaviors demonstrated that these materials are pH- and thermo- responsive. In addition, the obtained hybrid intelligent hydrogels were found to have sustained release profiles.In the first part of this thesis, alginate/CaCO3 hybrid beads with pH- and thermo-responsive drug release property were prepared under compressed CO2. Novel temperature responsive aliphatic poly(urethane-amine) (PU) with suitable aliphatic urethane and amine units were employed as the thermal sensitive composition. The obtained microspheres were characterized by IR, XRD, SEM, TG and EDS. Results illustrated that the introduction of PU contributes the formation of a composite inorganic shell on the microspheres surface, resulting in the beads with improved strength and mechanical properties. The swelling and indomethacin drug release behaviors demonstrated that these microspheres are pH- and thermo-responsive and show a decreased drug release rate.In the second part, sodium alginate is hydrophobically modified by grafting 1-octylamine via chemically induced radical graft copolymerization. The grafting was successful as proved by IR. The grafted alginate was then blended with PNIPAAm to prepare thermal responsive hydrogel microspheres. Thus, swelling and drug release behaviours of the obtained microspheres were found to be pH- and thermo-responsive.In the third part, a series of biomineralized polysaccharide alginate membranes containing palmitic acid as a hydrophobic component were prepared with a one step method. The membranes were characterized by IR, XRD, SEM, TG and EDS. Results demonstrated that the formation of calcium phosphate could be observed in the biomineralized membranes. Indomethacin release behaviour of the developed membranes was found to be pH- and thermo- responsive. In addition, the release profile could be sustained, indicating that the inorganic-organic hybrid biomineralized polysaccharide membrane could prevent the permeation of the encapsulated drug and reduce the drug release effectively.