β-Glycerol phosphate/genipin chitosan hydrogels: A comparative study of their properties and diclofenac delivery

Thermosensitive hydrogels based on polysaccharides are suitable candidates for the design of biodegradable and biocompatible injectable drug delivery systems. Thus, the combination of chitosan (CHI) and β-glycerol phosphate disodium salt (β-GP) has been intensively investigated to develop thermo-induced physical gels. With the aim of exploring the possibilities of optimization of these hydrogels, in this work, chitosan, β-GP and naturally extracted crosslinking agent, genipin (GEN), have been successfully combined, obtaining co-crosslinked hydrogels with both in situ physical and covalent crosslinking. A wide range of β-GP concentrations have been selected in order to analyze its influence on a variety of properties, including gelation time, pore size, water uptake ability, in vitro hydrolytic and enzymatic degradation, mucoadhesion and mechanical and rheological properties. Furthermore, the potential application of the developed systems for the administration and controlled release of an anti-inflammatory anionic drug, such as diclofenac, has been successfully demonstrated.