Microsphere absorption by the nasal mucosa of the rat.

Uptake by nasal epithelial tissue of fluorescent polystyrene latex microparticles of diameter 0.8 micron was studied in rats after single intranasal dosing. At intervals following administration, particles were observed in the blood compartment. Peak concentration of particles occurred in normal animals at 10 min. At 24 h some particles were still present in these animals' circulation. Throughout the sampling, tracheotomised animals demonstrated a steady state presence of particles. These results show that the uptake and translocation of solid particles does also take place through the nasal epithelial lining as it does through gut epithelia, possibly through the nasal associated lymphatic tissue.