Effects Of Phenylethyl Resorcinol Cationic Nanoliposomes On Enhancing Permeability And Whitening

Phenylethyl resorcinol(PR),a highly effective whitening active ingredient,is a highly active tyrosinase inhibitor,which can effectively inhibit the synthesis of melanin in melanocytes.However,PR has poor photothermal stability,easy oxidation and discoloration,and poor solubility,which makes it difficult to be absorbed through the skin and absorbed by melanocytes.Nanoliposomes have good cell affinity and biocompatibility,which can effectively increase the stability of active ingredients and improve the solubility of active ingredients.Human skin and skin cells are negatively charged.The modification of nanoliposomes into positively charged cationic nanoliposomes can promote the transdermal absorption of the active ingredients and increase the uptake of the active ingredients by target cells,thus enhancing the efficacy of the active ingredients.Oxidative stimulation can up-regulate the activity of tyrosinase and accelerate the production of melanin.Melanin in the synthesis of melanocytes,gradually transferred to the skin stratum corneum,thus affecting the complexion.Carnosine(CAR)is a natural antioxidant,which can effectively eliminate ROS.Nicotinamide(NA)is an inhibitor of melanosome migration.Therefore,multi-effect and multi-target whitening effect can be achieved by co-encapsulating PR,CAR and NA with positive nanoliposomes.Phenylethyl resorcinol cationic nanoliposomes(PR-CLPs)were prepared to enhance the skin permeability and melanocyte uptake of PR.Cationic nanoliposomes co-encapsulating with PR,CAR and NA(PCN-CLPs)were developed to achieve transdermal co-delivery and synergy of whitening active compounds.The main research work of this paper is as follows:(1)Preparation of PR-CLPs and characterization of their physical and chemical properties.The mean particle size,polydispersity index(PDI)and Zeta potential of PR-CLPs were 102.1 ± 1.3 nm,0.221 ± 0.010 and +23.7 ± 1.7 m V,respectively.The drug loading efficiency and encapsulation efficiency were 8.8% ± 0.1% and 90.3% ± 1.3%,respectively.PR-CLPs stored at 4℃ for 3 months showed no significant changes in particle size,PDI and Zeta potential.In vitro release results showed that PR-CLPs showed a sustained release behavior.The results of PR-CLPs in vitro transdermal experiments showed that the skin retention and cumulative permeation per unit area of PR in 24 h were significantly higher than those of free phenylethyl resorcinol(free PR)and phenylethyl resorcinol nanoliposomes(PR-NLPs)(P < 0.05).To evaluate the whitening efficacy of PR-CLPs in vitro in mouse melanoma cells(B16F10 cells).Cellular uptake behavior was studied by laser confocal analysis and flow cytometry.The results showed that cationic nanoliposomes could significantly promote the uptake of encapsulated fluorescent dyes by melanocytes.Compared with free PR and PR-NLPs,PR-CLPs significantly increased the inhibition rate of tyrosinase activity in B16F10 cells(P < 0.01)and significantly reduced melanin production in B16F10 cells(P < 0.05 or P < 0.01).(2)Cationic nanoliposomes co-encapsulating with PR,CAR and NA(PCN-CLPs)were prepared and their physicochemical properties were characterized.PCN-CLPs mean particle size,PDI and Zeta potential were 91.6 ± 1.1 nm,0.238 ± 0.006 and +24.3 ± 1.5m V,respectively.The drug loading efficiency of PR,CAR and NA were 6.6% ± 0.3%,3.7% ± 0.1% and 4.2% ± 0.1%,respectively.The encapsulation efficiency of PR,CAR and NA were 90.6% ± 2.3%,61.8% ± 3.6% and 62.3% ± 1.5%,respectively.PCN-CLPs stored at 4℃ for 3 months showed no significant changes in particle size,PDI and Zeta potential.The in vitro release results showed that the PR,CAR and NA encapsulated by PCN-CLPs showed obvious sustained release behavior.The in vitro transdermal results showed that PCN-CLPs significantly increased the skin permeation and retention of PR,CAR and NA compared with the same dose of free PCN and PCN-NLPs(P < 0.05 or P <0.01).B16F10 cells and human keratinocytes(Ha Ca T cells)were used to evaluate the whitening efficacy of PCN-CLPs in vitro.The results showed that,compared with free PCN and PCN-NLPs,the inhibition rate of tyrosinase activity in B16F10 cells was significantly increased by PCN-CLPs(P < 0.01)and significantly reduced melanin production in B16F10 cells(P < 0.05 or P < 0.01);Significantly increased the survival rate of Ha Ca T cells in oxidative injury model(P < 0.05 or P < 0.01),reduce the production of ROS(P < 0.01);The migration of melanosomes from B16F10 cells to Ha Ca T cells was significantly inhibited.(3)The hen’s egg test on the chorioallantoic membrane and human patch test were used to evaluate the safety of PCN-CLPs.The results showed that PCN-CLPs had no irritation to the chorioallantoic membrane and no obvious irritation to human skin.Human melanin measurement test and human face image collection to evaluate the human whitening effect of 2.5% PCN-CLP whitening cream.The results showed that,compared with free PCN group and PCN-NLPs group,the amount of melanin in the flexure side of the forearm of subjects in the PCN-CLPs group decreased significantly after 28 days(P <0.05),the facial whitening degree of subjects was significantly increased(P < 0.05),the melanin was significantly decreased(P < 0.05).This study shows that cationic nanoliposomes can effectively promote the transdermal permeation of whitening active ingredients and increase the uptake of melanocytes.Co-delivery of active ingredients with different mechanisms of action can achieve synergistic effect.The research work provides theoretical and experimental basis for the development of novel whitening active ingredient nanocarrier.