Drug loaded on the injectable polymer hydrogels to reach safely to the
targeted site and elute slowly has significant advantages. For this purpose, many
techniques have developed for crosslinking (CL) of the polymers chain including
physical and chemical CL. Chemical CL (covalent CL) is more effective approach
because it provides significant mechanical strength as compared to physically crosslinked
hydrogel. There are a number of factors including light, pH, electric current, and
glucose are used to stimulate the loaded drug release. For this purpose, various
modifications have been made in the hydrogels by changing the CL strategies. In this
chapter, a variety of CL techniques have been described along with its advantages and
limitations including physically CL, chemically CL, hydrogen-bonding interaction etc.
Moreover, the response of hydrogels to different stimuli in environment like
temperature, pH, electric current, light and glucose sensitivity are also explained with
few examples reported in the previous literature. Composite materials (CT) is one of
the most emerging materials in various scientific and technological sectors and are
effective in various biological applications. Therefore, the CT based hydrogels, are also
included in the discussion of this chapter. The role of dexamethasone, methylene blue and vitamin B12 loading and release via CT based hydrogel are described in this
chapter.
Keywords: Chitosan, Composites, Cross-linking, Drug Delivery, Hydrogels,
Stimuli Responsive.
