Synthesis and biomedical application of polymer vesicles composite hydrogels

Nanocomposite hydrogel attracts increasing interest in drug delivery field on account of combining advantages of nanocomponents and hydrogels on the controlled drug release and biocompatibility. Polymer vesicle composite hydrogels were designed for ophthalmic drug delivery in the work. Polymer vesicle was fabricated by polymerization in situ and assembling of macromolecule (heparin/chondroitin sulphate)-monomer (diethylaminoethyl methacrylate) system. Vesicle size and zeta potential could be adjusted by many factors such as the property of macromolecule and cross-linking of vesicle. Vesicle was further characterized and confirmed by transmission electron microscopy. Polymer vesicle laden hydrogels were obtained by photopolymerization in situ. The transparency of composite hydrogel declined with increase in vesicle concentration. The equilibrium water content and water loss showed that polymer vesicle composite hydrogel with higher vesicle concentration was in a higher swollen state. The dynamic viscoelastic properties showed that all polymer vesicle composite hydrogels had some characteristics of cross-linked elastomers. After freeze-dried, polymer vesicle composite hydrogels had a coarser surface with scattered small particles. The drug loading and releasing behaviours as a function of initial drug immersing concentration were detected to evaluate the drug loading and releasing capacity of hydrogels using orfloxacin as a model drug. The results indicated that polymer vesicles in hydrogels could hold or help to hold drug molecules and slow down orfloxacin release speed or keep orfloxacin stably remain for a certain period of time in hydrogels.