In order to improve the drug loading

urea was used to insert into the montmorillonite interlayer by solid-phase grinding method. After this process

the ibuprofen was loaded by the solution blending to obtain ibuprofen/urea-montmorillonite (S(+)-IBU/urea-MMT) composite. The composites were characterized by X-ray diffraction (XRD) and Fourier transformed infrared (FT-IR) spectroscopy. The in vitro drug release behaviors of S(+)-IBU/urea-MMT were investigated by the dialysis method. Three models of in vitro drug release could be used to simulate the release performance of the S(+)-IBU/urea-MMT composites. The results show that the urea was intercalated into the montmorillonite layers

and the interlayer spacing of montmorillonite was enlarged from 1.20 to 1.79 nm. The maximum loading capacity of S(+)-IBU on the modified montmorillonite was 227.9 mg·g-1

increased by a factor of 30%. In the artificial gastric juice (pH 1.2) and in the artificial intestinal juice (pH 6.8)

the in vitro cumulative amount of the composites were 19.2% and 88.4% respectively. The variation of in vitro release rate can be well described by the zero order kinetics model.