8.5.2　NPs based on biomedical polymers

The use of polymer NPs to carry drugs is an important strategy in the second generation of TDD technology.Polymer NPs can not only reduce the degradation of drugs and enhance the transdermal penetration ability of drugs，but also achieve controlled drug release.Polymer NPs usually accumulate in hair follicles and achieve transdermal delivery through the transcellular pathway.Polymer NPs encompass natural polymer NPs（e.g.，chitosan，albumin NPs）and synthetic polymer NPs（e.g.，PLGA，dendrimer NPs）.The application of NPs in TDD technology is detailed in Chapter 6.(https://www.daowen.com)