Abstract:

The diol-type ginsenoside W/O nanoemulsion was prepared and its anti-aging mechanism of skin was studied. According to the solubility of the diol-type ginsenoside and the pseudo-ternary phase diagram, we investigated the nanoemulsion prescription, and determined the nanoemulsion morphology, particle size distribution, drug loading and stability. The Franz diffusion cell was used to study the in vitro transdermal properties of the nanoemulsion, and the effect of local administration of the nanoemulsion on male mice skin microstructure was investigated by HE staining method. And the anti-aging effects of nanoemulsion was investigated as well. The best prescription for diol-type ginsenoside W/O nanoemulsion is isopropyl palmitate as oil phase, Span 80 as emulsifier, 1, 2-propylene glycol as co-emulsifier, and K_m value=2. The ratio of oil phase to mixed emulsifier is 7.5∶2.5. The nanoemulsion has a round and uniform appearance, the average particle size is 17 nm, the particle size distribution value is 0.064, and the glycol-type ginsenoside content is 4.2 mg/mL. The physical stability is good. The results of in vitro transdermal experiments show that the cumulative permeation of the ginsenoside nanoemulsion is 1.640 7 mg/cm ² after 12 h of transdermal administration, which is 2.832 2 times that of the cumulative permeation of 12 h in aqueous solution. The skin retention is 0.018 4 mg/cm², which is 1.179 5 times that of the skin retention of the aqueous solution. The HE staining experiment is found that the structure of the epidermal structure is basically intact without pathological changes after using the ginsenoside nanoemulsion. The dermal collagen fibers are dense and abundant, mostly arrange in bundles. The results of animal experiments show that hydroxyproline, type I collagen, type III collagen, matrix metalloproteinase inhibitor 1 （TIMP-1）, and matrix metalloproteinase inhibitor 2 （TIMP-2） content are significantly higher than the blank group and the ginsenoside aqueous solution group, and the contents of matrix metalloproteinase 1 （MMP-1） are significantly lower than those in the blank group and the aqueous solution group. The prepared ginsenoside nanoemulsion has good stability and excellent transdermal performance, and can achieve anti-aging effects by inhibiting the decomposition of collagen and increasing the collagen content in the skin.

Key words: diol type ginsenoside, W/O nanoemulsion, skin retention, anti-skin aging