Application Of Polymer Roller Microneedle Pretreatment In Melasma

Microneedles(MN)have the advantages of painlessness,good biocompatibility,and high patient compliance,and have received widespread attention.However,the application of patch-type microneedles for drug delivery to large areas of skin and special parts of the body is restricted.The metal roller microneedles currently on the market are poor in biocompatibility and pose great safety problems.Melasma is prone to occur on the cheeks,forehead,lips and other parts of the face that are susceptible to sunlight.Some patients have large lesions and are prone to recurrence,which brings great troubles to patients,especially women.Topical application of hydroquinone cream is the most common treatment method,and the penetration of the drug is not good.In order to solve these problems,the main research contents of this paper are as follows:1.Explored a new method of manufacturing detachable polymer roller microneedles.First,the polymer microneedle sheet was prepared by the mold hot pressing method,and then solidworks was used to mechanically design and 3D print the detachable roller model.The needle and the detachable roller model were adhered tightly through PET mucosa.Characterization of mechanical properties,sealing membrane penetration experiments and in vitro penetration experiments showed that the roller microneedle adopts a conical needle shape and can successfully penetrated the back skin of mice;the mechanical stability was good.After rolling 15 times on the eight-layer sealing membrane,The first layer of parafilm still maintained a penetration rate of 90%.The roller microneedle with a microneedle height of 400 μm and a roller diameter of 25 mm exhibits relatively superior mechanical stability;the roller diameter increased,the penetration area increased,and the drug The penetration rate was increased.2.A mouse model of melasma was constructed by ultraviolet irradiation.A polymer roller microneedle with a microneedle height of 400 μm and a roller diameter of 25 mm is used for pretreatment to treat melisma mice.The measurement of SOD activity and MDA content in skin and liver tissues showed that the SOD activity and MDA content in the skin and liver tissues of the UV group mice decreased,indicating that this paper successfully constructed a mouse model of melasma.The SOD activity increased and the MDA content decreased in the two treatment groups,and the treatment effect of the polymer roller microneedle pretreatment group was better.The tissue sections and OCT photos reflected the changes in the skin tissue of mice with melasma,and the results showed that the UV+HQC+MNR group had a better treatment effect.