Objective: To prepare nasal dry powder inhaler

preparation of microspheres which assembled by baicalin nanoparticles with chitosan as carrier

in vitro release properties and nasal mucous membrane permeability were invesgated. Method: Primary nanoparticles were prepared by ionic cross-linking

nanoparticles were assembled to microspheres by spray drying method.Particles were characterized by scanning electron microscopy (SEM)

X-ray diffraction (XRD)

differential scanning calorimetry (DSC) and so on

its in vitro release in artificial nose liquid electrolyte and permeability under simulated human nasal mucosa were investigated. Result: Average particle size of primary particles was (170.5±2.3) nm

while the second particles was (6.8±0.4) μm with drug dispersed as amorphous form in them.Specific energy of microspheres was (5.46±0.37) mJ · g-1

pressure drop was 0.323 kPa when air kept speed of 2 mm · s-1 through powder bed with force was 15 kPa.And the second particles could decomposed into primary nanoparticles in simulated nasal electrolyte solution.Cumulative release rate of baicalin was (78.85±2.71)% in 33 hours and release curve accorded with Riger-Peppas model.Value of cumulative release rate per unit area of microsphere was 1.77 times that of the pure baicalin sample. Conclusion: These prepared microspheres can release primary particles with good fluidity

permeability and a certain sustained-release effect

it can improve nasal mucous membrane permeability of baicalin.