Objective: The aim of the present study was to design an efficient delivery system with an anticipated swelling and drug release properties for a prolonged drug release as well as to target colon for various hydrophilic drugs.
Method: For this purpose, the pH-responsive hydrogel comprising a combination of Eudragit and acrylic acid was formed. The hydrogels were characterized for spectral (FTIR), thermal (TGA/DSC), structural (XRD), and morphological (SEM) investigations. Oral tolerability was assessed in rabbits for biocompatibility and oral use of the prepared hydrogels. Results: The results showed that an increased incorporation of Eudragit and cross -linking agent retorted the swelling, drug loading, and drug release properties at both acid (pH 1.2) and basic pH (pH 6.8 and 7.4) , while acrylic acid presented the inverse results. The oral tolerability and toxicity studies depicted that the developed hydrogels were safe up to 3800 mg/kg body weight and caused no hematological or histopathological changes when compared with the control group. Conclusion : Therefore, the newly developed formulations presented adequate swelling, drug loading, release behavior, and biocompatibility properties and thus can be used as a promising tool for the colonic delivery of various hydrophilic drugs.