Abstract：MCM-41 with pore diameters of 3 nm prepared by hydrolysis of silicate ester was used as the carrier of uniconazole. The pesticide molecules were loaded with impregnation under subatmospheric pressure. The systems were characterized by XRD， BET， TEM， SEM and TG. Subsequently， the formed composite was coated with γ-PGA (M.W.≈9 180 Da) to furnish drug controlled release systems. The controlled release effect of different systems was investigated in various ethanol-PBSaq solutions. The controlled release mechanisms were investigated by fitting the kinetic models of zero-order release， first-order release， Higuchi and Rigter-Peppas. The results showed that uniconazole was adsorbed both on the outer surface and in the holes of MCM-41. The impregnation under subatmospheric pressure enabled incorporation of uniconazole molecules into the holes of 3 nm with monolayer adsorption. The appropriate molecular weight was essential to obtain release system of MCM-41@γ-PGA with uniform shell thickness and good dispersity， and polyethyleneimine was used to bridge silica layer and γ-PGA layer. The release of system， including uncoated by γ-PGA was unfitted to zero-order release， first-order release model， or Higuchi models. Rigter-Peppas release kinetics model was fitted well， and the Fick diffusion mechanism was followed.
2019, Vol. 53 
