Co-encapsulation of vitamins B6 and B12 using zein/gum arabic nanocarriers for enhanced stability, bioaccessibility, and oral bioavailability.

The present study aimed to fabricate a co-deliver system using zein/gum arabic (GA) polymers for enhanced stability and bioavailability of vitamins (B6 and B12). The anti-solvent evaporation method was used for the preparation of PC-ZG NPs (pyridoxine-cyanocobalamin zein-GA nanoparticles). The process conditions were statistically optimized using the design of Box-Behnken. The optimized conditions produced small-sized particles (∼170 nm) with high zeta potential (-31 mV) and efficient encapsulation for pyridoxine (61.6%) and cyanocobalamin (56.3%). Scanning electron microscopy, x-ray diffractometry, and Thermogravimetric analysis results confirmed that the developed formulation had a roughly spherical shape and an amorphous character with better thermal stability compared to free-forms of the vitamins. The results of the storage study showed no significant changes in nanoparticle size at 4, 25, and 37°C over a 90-day period. However, a slight variation in retention of the vitamins was observed during the initial period. The bioaccessibility of both the vitamins from PC-ZG NPs ranged between 56% and 62% post 6 h simulated digestion. In Caco-2 cells, the cellular uptake of vitamins was higher from nanoforms compared to the free-forms. Further, oral administration of PC-ZG NPs in rats exhibited 4.8- and 2.2-fold increases in relative bioavailability of vitamins B6 and B12, respectively. A significant reduction of plasma homocysteine level (p ˂ 0.05) in the treated group was also observed. Together, these results suggest that the developed nanoformulation has improved physicochemical properties with enhanced bioavailability and, hence, could be used as an effective delivery system for the vitamins in food and nutraceutical products.