Lecithin/Cholesterol/Tween 80 Liposomes for Co-Encapsulation of Vitamin C and Xanthoxylin

Co-encapsulated hydrophilic vitamin C (Vc) and hydrophobic xanthoxylin (GX-50) liposomes (L-Vc-GX-50) were prepared using ethanol injection and ultrasonic methods and characterized by dynamical light scattering, ζ-potential, cryogenic transmission electron microscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy, antioxidant capacity, tyrosinase activity, and in vitro permeation measurements. L-Vc-GX-50 are formed by the assembly of egg yolk lecithin, cholesterol, and tween 80, with Vc and GX-50 encapsulated in their hydrophilic and hydrophobic cavities, respectively. By considering the hydrodynamic radius (Rh), ζ-potential, and encapsulation efficiency (EE) of L-Vc-GX-50, the optimum formulation was determined to be egg yolk lecithin/cholesterol/tween 80/GX-50 or Vc (15:3:3:1, w/w) with phosphate buffer (pH 6.8, 0.01 M). The as-prepared L-Vc-GX-50 have an average Rh of 114 nm, a negative ζ-potential (−23.63 mV), a high EE of Vc (73.3%) and GX-50 (87.4%), and a unilamellar vesicle structure. Compared co-encapsulated L-Vc-GX-50 with single encapsulated Vc or GX-50 liposomes (L-Vc or L-GX-50), the EE of Vc in L-Vc-GX-50 is obviously higher than that of L-Vc, while the EE of GX-50 in L-Vc-GX-50 is similar to that in L-GX-50; the antioxidant capacity and tyrosinase inhibition activity of L-Vc-GX-50 are higher than those of L-GX-50 or L-Vc. The in vitro permeation data indicate that the final cumulative permeation amount of Vc and GX-50 in L-Vc-GX-50 can reach around 2.1 and 1.3 mg/cm2, respectively. The release kinetics fitting data show that the release kinetics of L-Vc-GX-50 follows the Korsmeyer–Peppas model and that the release of active ingredients is mainly dominated by the synergistic effect of diffusion release and rupture release. Moreover, L-Vc-GX-50 has good low-temperature storage stability, and the storage stability of GX-50 in L-Vc-GX-50 is significantly improved compared to L-GX-50. The main objective of this study is to improve the instability of Vc and the insolubility of GX-50 in cosmetics.