In order to combine the advantage of a biopolymer with clay in a drug delivery system

the simple solution-mixing processing technique was used to prepare carboxymethyl chitosan/organic rectorite nanocomposites(COR).The rectorite (REC) was modified with cetyltrimethyl ammonium bromide.A study on these nanocomposites’ microstructures and configurations was conducted through observation of X-ray diffraction (XRD)，fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).The results indicated that carboxymethyl chitosan chains were inserted in silicate layers to form the intercalated nanocomposites

the interlayer distance of rectorite was magnified and rectorite dispersed well in carboxymethyl chitosan matrix.Bovin serum albumin(BSA)

as a model protein drug

was incorporated into the nanocomposite/alginate microspheres.The results showed that their encapsulation efficiency and controlled release property were better than those of pure carboxymethyl chitosan/alginate microspheres.The encapsulation efficiency increased from 56% to 86%. In vitro release studies showed a burst effect and a slow and continuous release followed

and the release time prolonged from 24 h to 72 h.Drug release from nanocomposite/alginate microspheres was pH sensitive.The release rate was slow at pH 1.2 and rapid at pH 7.4

which can be used for drug delivery to the intestinal and colon.Therefore

the carboxymethyl chitosan/organic rectorite nanocomposites are of great potential in the biomedical field.