Current Status and Future Prospects on Nanodelivery Systems Targeting the Small Intestine for Absorption of Bioactive Substances.

The undesirable properties of bioactive substances (such as poor solubility and low stability) and various barriers in the gastrointestinal tract (gastric acid, digestive enzymes, mucus and intestinal epithelial cells) hinder their absorption and utilisation by the human body. Nanodelivery systems have been proven to effectively address the above problems, particularly targeted nanodelivery systems, which have more advantages in improving the bioavailability of bioactive substances. However, many studies have not included all barriers. Furthermore, given that the small intestine is the main site for the absorption of bioactive substances in the human body, this review primarily discusses targeted nanodelivery systems designed for the gastrointestinal barrier and summarises how to construct a nanodelivery system that can resist the adverse effects of the gastrointestinal tract and target the small intestine for the absorption of bioactive substances. This paper proposes that the ideal system is the active targeted nanodelivery system that targets enterocytes and its future development trend is discussed. This review aims to provide new insights for the rational design of nanodelivery platforms that efficiently target the small intestine and promote the absorption of bioactive substances, as well as promote the development of fields such as personalised nutrition and nutritional intervention.