| Vitiligo is a complex decolorizing skin disease caused by melanocytes function loss or disorder.Its pathogenesis is not clear,by far autoimunity is the main etiology theory.Studies have shown that IFN-y can directly cause senescence and apoptosis of melanocytes,the release of local IFN-y also causes aggregation of melanocyte-specific CD8+T cell,damages melanocytes and causes vitiligo symptoms.IFN-γ conducts signals to achieve its biological effects mainly through the JAK-STAT pathway,so JAK-STAT pathway inhibitors will play a role in the treatment of vitiligo.Tofacitinib is an oral Janus kinase(JAK)inhibitor developed by Pfizer in the United States.Studies have shown that oral tofacitinib had a certain therapeutic effect on vitiligo.Oral tofacitinib preparations have some side effects such as gastroinexperimentinal reactions and upper respiratory infections and drugs delivered to the skin by circulation of blood are little。Tofacitinib has a small molecular weight and can be prepared as a transdermal formulation.However,the solubility of teicotinib is poor,so the general transdermal preparation is difficult to achieve the treatment need,we need some methods to increase the content of the tofacitinib or enhance the percutaneous penetration in the same content.Commonly methods to promote percutaneous penetration of drugs are using transdermal enhancers or using lipid nanocarriers,lipid nanocarriers have the advantage of high affinity for the skin.The subject of this study is to prepare the tofacitinib loaded nanostructured lipid carriers,in order to increase the drug transdermal properties and intradermal drug retention,reduce adverse reactions.In our study,tofacitinib loaded nanostructured lipid carriers were prepared by thin-film ultrasonication with 54%soybean lecithin,36%glyceryl monostearate,10%tofacitinib as lipid nanoparticles compositions and 2%sodium dodecyl sulfate solution as dispersion.The encapsulation efficiency of the prepared nanostructured lipid carriers was 63.62%,the particle size was about 150 nm,the polydispersity index was 0.212,and the morphology under the transmission electron microscope was nearly spherical.The cytotoxicity of nanostructured lipid carriers was studied by MTT,which showed that nanostructured lipid carriers were almost non-toxic to human epidermal melanocytes.The cells pharmacology of tofacitinib loaded nanostructured lipid carriers was studied by immunofluorescence,which showed that the intracellular content of P-JAK2 protein was significantly lower than that of the pretreatment with the tofacitinib solution,indicating that the inhibitory effect of the tofacitinib-loaded-nanostructured lipid carriers on IFN-y-activated JAK-STAT pathway was stronger than that of tofacitinib solution.The transdermal permeation experiments were conducted to study the transdermal properties of tofacitinib loaded nanostructured lipid carriers using Franz diffusion cells.In the transdermal experiments,we found that tofacitinib loaded nanostructured lipid carriers had good transdermal properties,the drug content in the skin was higher than tofacitinib solution.In vitro release assay showed that nanostructured lipid carriers had a sustained release effect on the release of tofacitinib.The hydrogel contained tofacitinib-loaded-nanostructured lipid carriers or aqueous solution were prepared using sodium carboxymethyl cellulose.Mice skin irritation experiments showed that the prepared tofacitinib hydrogel had no irritation to the intact skin and had a slight irritation to the damaged skin.In vitro release studies showed the release of drug in the hydrogel was slower than that of the aqueous solution or the nanolipid carrier dispersion.In the transdermal experiment in vitro,the transdermal steady-state permeation rate and accumulated amount through the per unit area of the nanolipid carrier hydrogel were much lower than that of the hydrogel prepared by the tofacitinib solution,were 37%and 31%respectively,and the intradermal drug content was higher than that of the tofacitinib solution,about 2.96 times.In summary,encapulating tofacitinib into nanostructured lipid carriers enhanced its ability to enter the cell and enhanced its transdermal properties.Compared with hydrogel prepared by tofacitinib solution,hydrogel prepared by the tofacitinib nanostructured lipid carriers had reduced amount of drugs through the skin.It could avoid excessive drug into the blood circulation,reduce adverse reactions and increase drug content in the skin,which is beneficial to the treatment of vitiligo. |
