Stimuli-responsive, biocompatible hydrogel derived from glycogen and poly(N-isopropylacrylamide) for colon targeted delivery of ornidazole and 5-amino salicylic acid

In the present article, a novel biocompatible and stimuli-responsive hydrogel (cl-Gly/pNIPAm) has been fabricated through free radical polymerisation using biopolymer glycogen (Gly), N-isopropylacrylamide (NIPAm) monomer and ethylene glycol dimethacrylate (EGDMA) crosslinker. Several grades of hydrogels have been developed and an optimized grade (i.e. c-Gly/NIPAm 4 with higher % crosslinking) has been used for characterisation and application towards colon targeted drugs carrier. The temperature and pH sensitivity of the cl-Gly/pNIPAm hydrogel have been studied by assessing equilibrium swelling at 25/37 °C and pH 1.2/7.4. The LCST of the developed hydrogel has been determined and found to be in the range of 32.5–34 °C. The degradation kinetics of the hydrogel has been performed. The hydrogel demonstrates good compatibility towards human mesenchymal stem cells (hMSCs). It is degraded by hen egg lysozyme. The synthesized hydrogel can load colon targeted drugs, 5-amino salicylic acid (5-ASA) and ornidazole, efficiently and released both drugs in a controlled manner, while ∼96–97% of drugs remained stable after 2 months. The release kinetics and mechanism have also been studied.