Preparation And Properties Of Gelatin-Chitosan/Montmorillonite Drug-loaded Microspheres

The drug-loaded microspheres made by biodegradable polymer , has broaden prospects for application as drug-carrier in medicine field. Chitosan (CS) can be used as a new drug-carrier , for its in-toxicity, good biocompatibility and biodegradability. Gelatin (Gel) has no adverse reaction, no immunogenicity, and good biodegradability, and is widely applied. Gel/CS drug-loaded microspheres has been prepared by method of emulsifying-chemical crosslinking. But glutaraldehyde(GLA) ,the crosslinking agent used, is toxic to human at some extent. In this experiment, polymer had been intercalated into silicate lamellars of montmorillonite (MMT), to get a proper material properties and decrease the content of GLA. Acyclovir (ACV) is a kind of efficient broad-spectrum antiviral agent, but has bad oral medication-delivery absorption, and short half-life. So it's necessary to make it sustained-release agency, to extend the duration of effect.In this experiment, Gel-CS/MMT intercalated composites were prepared, the mechanical properties and swelling properties were researched, and the effect made by the ratio of Gel to CS and the content of GLA were discussed. On this basis, Gel-CS/MMT-ACV drug-loaded microspheres were prepared by method of emulsifying-chemical crosslinking, characterized by X-ray diffractometer(XRD), scanning electron microscope(SEM), polarization microscope, laser grain size analyzer. Its sustained-release properties had been researched by ultraviolet-visible spectrophotometers(UV-spectrophotometer), and the encapsulation efficiency and the releasing behavior were determined.The results show that,the breaking stress and breaking strain of Gel-CS/MMT intercalated composites reach the max value ,when the content of GLA is proper. High or low content of GLA have effect on mechanical properties. And the young′s modulus decreased with the reducing of the content of GLA. When the ratio of Gel to CS increased, the breaking stress and breaking strain of Gel-CS/MMT increased correspondingly. When the ratio of Gel to CS was moderate, the materials got higher young′s modulus. The swelling degree increased when the ratio of Gel to CS increased or the content of GLA decreased. With the same content of MMT, preparing the drug-loaded microspheres at a certain ratio of Gel to CS by some way , can get more regular microsphere. The diameter of microsphere concentrated on 2600nm. In comparison, the microsphere of initial drug administration content of 0.005, has the highest drug utilization. The sustained-release drug-loaded microspheres has long effectiveness and high utilization.