Stimuli-responsive polymers for oral insulin delivery

Abstract

Abstract Advances in polymer science have enabled to mimic the response of living system to external stimuli by developing a group of polymers that can undergo reversible large, significant physiochemical changes in response to small external changes in the environmental conditions, such as pH, temperature, light, ionic factors, magnetic or electric field, biological molecules, etc. Challenges confronted by oral insulin delivery now-a-days, demand sensitive efficient systems for successful oral delivery with improved oral insulin bioavailability not compromising with the safety and hypoglycemic episodes. The “stimuli responsive” or “smart” polymers have gained considerable attention in the regard because their changes are reversible; they are capable of releasing entrapped insulin at the appropriate time and site of action in response to specific physiological triggers. Moreover, these polymers exhibit a nonlinear response to a small stimulus owing to macroscopic alteration in their structural properties. Their responses also vary widely from swelling contraction to disintegration. Synthesis and application of stimuli- responsive polymers with better biodegradability and greater biocompatibility would enhance the efficacy of oral insulin delivery. The most fascinating features of the stimuli-responsive polymers arise from the versatility and their tunable sensitivity. However, slow response time can be a significant weakness of stimuli-sensitive polymers. Therefore, combinatorial synthesis can help in tuning the polymer sensitivity to a given stimulus within a narrow range. In this chapter, we will highlight various applications and the mechanism of action of stimuli-responsive polymers in advanced oral insulin delivery.