POS8-1505
Enhanced chemical stability and oral bioavailability of retinol encapsulated in O/W nanoemulsion stabilized by cycloamylose-catechin complexes
Topic
S8. Frontiers of Functional Polymers in Biology and Medicine
When and Where
Sep 30, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Heesuk KIM
Jinhye BAE
Presenter(s)
In-Geun Jung (Seoul National University)
Co-Author(s)
Abstract
Retinol is a lipophilic form of vitamin A with important pharmacological activities for human health. However, its chemical instability and low bioavailability remain major challenges for effective oral delivery. This study aimed to improve the chemical stability and oral bioavailability of retinol-loaded oil-in-water (O/W) nanoemulsions by incorporating cycloamylose (CA)-catechin (CT) complexes as antioxidant stabilizers. CA, a starch-derived cyclic α-1,4-glucan with a hydrophilic surface and hydrophobic cavity, was employed as a polymeric host to form inclusion complexes with CT, thereby enhancing the aqueous solubility and chemical stability of CT. The incorporation of CA-CT complexes into the emulsions improved their physicochemical properties, resulting in higher retinol encapsulation efficiency and smaller droplet sizes than the control emulsion (EM). Furthermore, CA-CT complexes promoted the interfacial localization of CT at the oil-water interface of the emulsions, effectively inhibiting lipid oxidation and thereby enhancing the chemical stability of retinol encapsulated in the oil droplets. Among the tested formulations, EM/CA5-CT, containing 5% CA, exhibited the highest storage stability, showing a 2.6-fold lower retinol degradation rate during storage at 40 °C for 28 days, indicating enhanced protection against oxidative degradation. After in vitro digestion, EM/CA5-CT also showed the highest retinol bioaccessibility, resulting in 2.59- and 2.38-fold higher cellular uptake and antioxidant activity, respectively. The enhanced physicochemical stability and bioaccessibility of retinol contributed to enhanced cellular absorption and antioxidant activity, ultimately leading to improved oral bioavailability. These findings demonstrate that CA-CT complexes are effective antioxidant stabilizers for emulsion-based delivery systems and provide a promising strategy for improving the oxidative stability and oral bioavailability of hydrophobic bioactives.
