| At present,microneedles transdermal delivery technology is becoming the focus of domestic and foreign scholars because of its excellent painless and minimally invasive drug delivery characteristics.The market demand of solid microneedles,hollow microneedles and dissolving microneedles in microneedle cosmetology and vaccine delivery is growing.Although there are many studies and reports on microneedles at home and abroad,the mainstream microneedle products in the market are still very limited.The forms of microneedle products are mainly confined to microneedle roller,microneedle cosmetic eye patches and microneedle vaccine patches.Among them,the main material of microneedle roller is silicon or metal stainless steel.The core technical problem of microneedle roller is the biocompatibility of microneedle.The manufacturing cost of microneedle cosmetic eye patches and microneedle vaccine patches is still high,and the expensive product price is difficult to reach the level of market popularization.Aiming at the problems of biocompatibility,tip integrity,forming cycle and batch production efficiency of microneedles in the process of microneedle moulding,the process of preparing polymer microneedles by ultraviolet imprint moulding and layered casting was studied.The process parameters affecting the quality of polymer microneedle moulding were analyzed.And nanoindentation,mechanical properties test,skin puncture and dyeing test in vitro,and insulin transdermal diffusion test were used to characterize the performance of microneedles,so as to ensure the clinical performance of microneedles.The main factors affecting the quality of photoresist microneedle forming were obtained through the experiment of ultraviolet imprint forming,including photoresist material,vacuum time and ultraviolet curing time,and the biocompatibility treatment method of ultraviolet imprint microneedle was put forward.On the premise of guaranteeing the quality of microneedle forming,the production efficiency of polymer microneedles was improved by utilizing the advantages of ultraviolet imprinting technology.Dissolving microneedles were prepared by two-step casting method.The optimum forming conditions of dissolving microneedles were studied.The forming defects of dissolving microneedles were analyzed.The operability and repeatability of the experiment were improved.In order to improve the drug delivery efficiency of dissolving microneedles,drug-loaded layered microneedles were successfully prepared by centralized loading of drugs to the tip of microneedles.In order to shorten the forming period of dissolving microneedles,closed bubbles were introduced into the microneedles,and bubble microneedles were successfully prepared.Finally,the transdermal delivery performance of dissolving microneedles was characterized by nanoindentation mechanics test,skin puncture and dyeing test of dissolving microneedles in mice,puncture and dissolution test of layered microneedles,and insulin transdermal diffusion test. |
