Evaluation of Bombax costatum Calyx Hydrogel as a Potential Insulin Delivery System

Hydrogel are a class of polymer materials that can absorb large amount of water without dissolving. The property of hydrogels to absorb water arises from hydrophilic functional groups attached to the polymeric backbone, while resistance to dissolution is due to physical or chemical crosslinking of the hydrophilic polymer chains. They are capable of responding to physical and chemical stimuli such as temperature pressure, pH, ionic strength, etc. In this study Bombax costatum calyx hydrogel was prepared to explore its potential in drug delivery. The study involves the encapsulation of insulin using swelling equilibrium method. The hydrogel was characterised using FT-IR; SEM techniques to study the structure of the networks. The swelling behaviour was studied in three different mediums (distilled water (pH6.9-7, pH 7.4 and pH 1.2) and at two temperatures (room temperature and 37°C). The hydrogel swell more in distilled water (pH 6.9-7) than in pH 7.4 and pH 1.2. Contrary to the trends observed in the swelling behaviour, the in vitro drug release in pH 7.4 was greater than that released in distilled water and pH 1.2. In conclusion, the smart behaviour exhibited by the hydrogel makes it a promising carrier in the site specific delivery of protein and peptide drugs to the colonic region.