Targeted delivery of hydrogels in human gastrointestinal tract: A review

The global demand for healthier food products has led to the introduction of functional foods fortified with bioactive agents, such as vitamins and nutraceuticals. Many of these bioactive agents have poor water-solubility, chemical stability, and bioavailability, which means delivery vehicles are needed to overcome these problems. The pharmaceutical industry also requires delivery vehicles to increase the administration and efficacy of drugs. In this study, we focus on the utilization of hydrogel-based delivery vehicles to overcome this problem. Hydrogels are formed by cross-linking biopolymer molecules to form a three-dimensional network that retains relatively high amounts of water. They can be used to encapsulate, protect, and control the release of bioactive agents in foods and pharmaceuticals. The functional attributes of hydrogels can be tuned for specific applications by manipulating their composition, dimensions, and internal structure. For instance, they can be designed to control the rate and extent of bioactive release under different conditions (such as pH, ionic strength, temperature, or enzyme activities). In this review, we discuss the structure, properties, and release mechanisms of hydrogels. In addition, we review previous applications of hydrogel-based delivery system for the targeted release of bioactive agents.