Introduction of passive targeting preparations

After intravenous injection, the distribution of passive targeting particles in the body depends on the particle size first, and nanocapsules or nanospheres smaller than 100nm can slowly accumulate in bone marrow. When it is less than 3μm, it is generally absorbed by liver and spleen macrophages; Particles larger than 7μm are usually intercepted by the smallest capillary bed in the lung by mechanical filtration and absorbed into lung tissue or alveoli by monocytes. The surface properties of particles play an important role in the distribution.