可溶微针可以安全，高效，无痛地将亲水性药物尤其是蛋白多肽类药物经皮递释。但是，受微针尺寸和制剂工艺等因素的影响，可溶微针的载药量十分有限，无法达到药物治疗剂量，限制了可溶微针技术在临床治疗中的应用。因此，本项目在先前疫苗微针制剂的研究基础上，提出核壳型可溶微针构建，采用可溶空心微针装载药物粉末的方式最大限度提高载药量和药物稳定性；同时，降低微针可溶辅料的使用可增加微针系统的适用性。本项目将系统地考察填充工艺，外壳应力，药物堆密度等对载药能力，微针强度的影响；通过体外透皮实验评价不同规格微针的经皮给药性能；通过动物实验考察微针的治疗效果。最终，以可溶微针的方式，建立药物粉末经皮给药体系，为高效透皮给药剂型的设计提供新思路和理论依据。

Dissolvable microneedle patches can be used for safe, efficient, and painless delivery of hydrophilic drugs like proteins, peptides and antibodies across the skin. However, due to their small capacity and processing technological limitations, the amount of drugs loaded on a microneedle is limited, which could not meet the requirement of clinical applications. Here, we propose to develop a dissolvable powder-encapsulated microneedle. Our hypothesis is that combining dissolvable hollow microneedle arrays with drugs in powder condition loaded in the cavities can maximize drug loading amount and enhances drug stability. Moreover, reduced use of excipients makes microneedle more compatible. In this study, the effect of filling processing, shell stress as well as bulk density on the loading capacity and strength of microneedle will be systematically evaluated. The transdermal tests will be conducted on healthy mice and pigs to investigate the fundamental properties and functionality induced by microneedle application. The long-term goal of this proposal is the establishment of transdermal delivery of powder drugs, which will provide novel strategy and theoretical basis for future design of transdermal drug delivery system.