Poly(lactic-co-glycolic acid) Nanoparticles for the Encapsulation and Gastrointestinal Release of Vitamin B9 and Vitamin B12

Deficiencies of vitamin B9 (VB9) and vitamin B12 (VB12) are very common among aged adults due to their poor oral bioavailability. However, the poor stability of these vitamins under storage and processing conditions hampers the development of nutraceutical products. In this work, poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were produced for the co-encapsulation of VB9 and VB12 to improve their stability and oral bioavailability for potential applications in nutraceutical products such as dietary supplements or functional foods. The NPs exhibited physicochemical properties suitable for oral delivery, with mean dimensions of around 190 nm and negative ζ-potential values of around −20 mV. The production process proved to be efficient with high encapsulation efficiency values for both vitamins (89% for VB9 and 71% for VB12), allowing for low production costs. The effects of different storage conditions on the NP colloidal stability and ability to retain the entrapped content were evaluated. NPs stored in the powder form at room temperature (RT) proved to be stable for at least 8 weeks. Simulated digestion studies demonstrated that the developed NPs can retain the entrapped vitamin content, therefore conferring protection against the gastrointestinal environment. This study highlights the ability of PLGA NPs to enhance the bioavailability of both vitamins by increasing their in vitro bioaccessibility. The nanoencapsulation of VB9 and VB12 allows improving their health-promoting properties, paving the way for the development of products for healthy aging.