浸渍法制备涂层聚乳酸微针

涂层高分子微针作为一种经皮给药系统，由于具有诸多优点而受到广泛关注。采用热压法制备了带有4个限位大针的聚乳酸微针；借助限位板的辅助作用，分别采用翻转浸渍法和漂浮浸渍法将聚乳酸微针浸渍到磺酰罗丹明B(模型药物)的涂层溶液中，制得涂层聚乳酸微针，涂层溶液与微针底板的距离约为300μm；力学性能测试结果表明，当位移为300μm时，单根针受力可达1N，表明涂层聚乳酸微针具有足够的力学性能刺入皮下；涂层聚乳酸微针的单根针载药量约为15ng，相对标准偏差为11.67%。此外，还制备了超疏水限位板，在其表面浸渍涂层溶液后几乎无溶液残留，解决了涂层溶液浪费的问题。

Preparation of coated polylactic acid microneedles by a dipping method

Polymer-coated microneedles have attracted extensive attention as a transdermal drug delivery system due to their many advantages. Polylactic acid microneedles with four limiting pins were prepared by hot pressing. With the aid of the limiting plate, coated polylactic acid microneedles were prepared by dipping into a coating solution of sulforhodamine B (as a model drug) by the flip dipping method and the floating dipping method. The distance between the coating solution and the bottom plate of the microneedle was about 300 μm. Mechanical property tests showed that when the displacement was 300 μm, the force of a single needle could reach 1 N, indicating that the coated polylactic acid microneedles have sufficient mechanical strength to penetrate the skin. The single-needle drug loading of the coated polylactic acid microneedles was about 15 ng, and the relative standard deviation was 11.67%. In addition, a superhydrophobic limiting plate was also prepared, and a negligible amount of solution remained after dipping the coating solution on its surface, eliminating any waste of the coating solution.