Research And Application Of Binary-drug Loaded Cosmetic Microneedles

With overexposed to ultraviolet B(UVB)irradiation and the increasing age of people,skin can cause a series of abnormal reaction,such as the formation of freckles,excessive pigmentation,and skin light damage.At present,a variety of whitening products are used in the cosmetic industry.The main types of cosmetic products are water,lotions,creams and other products.But the effective active ingredients of this type of cosmetic products have low transdermal delivery efficiency.Besides that,the gastrointestinal activity of edible cosmetic drugs will decrease and affect the therapeutic effect.In order to better treat the damaged skin overexposed to ultraviolet light,a MNs patch containing hydrophilic ascorbic acid and hydrophobic vitamin A palmitate was designed in this paper by introducing air bubbles into the microneedles to achieve synergistic administration and treat the damaged skin after UV irradiation.We confirmed that the MNs has a good mechanical properties an can penetrate the skin with the 100%penetration rate by the mechanical test.When the MNs patch was left under the skin for different time,it was found that the ascorbic acid at the tip of the needles was released prior to the vitamin A palmitate and achieved subcutaneous dissolution in 5-30 min.Next,we used a Franz diffusion cell to simulate the diffusion process,we concluded that the diffusion of the drugs from the microneedles to the simulated body fluids needs up to about 6 hours.In animal experiments,we established a model of ultraviolet irradiation damage by irradiating the skin of guinea pigs with ultraviolet rays.Through surface observation and tissue section display,we confirmed that the MNs have a better therapeutic effect than traditional smearing methods and can not only treat melanin deposits and can effectively repair damaged skin.In addition,due to the human body is uneven,traditional small pieces of microneedles cannot fit the skin.We have initially developed the formula of the flexible base and prepared the MNs patch with the 10 x 10 and 20×20 array using chitosan as a substrate material.We also conducted a preliminary investigation on the batch preparation process of hyaluronic acid cosmetic microneedles,and promoted the process of batch preparation of cosmetic microneedle patch.