Preparation And Drug Release Performance Of Intelligent Response System Based On Mesoporous Silica

Generally,the drug will have certain damage to the normal part in addition to the treatment of the diseased part in the process of treating diseases.Therefore,finding a drug carrier with targeted release is a research hotspot.Among them,mesoporous silica?MSN?has good biocompatibility,adjustable pore volume and other advantages,which has become an important research direction of drug carrier materials.Mesoporous silica has a certain ability of drug-loading,but it does not have the ability to target drug release.In this paper,mesoporous silica is prepared by copolycondensation of ethyl orthosilicate and cetyltrimethylammonium bromide as template.MSN-NH₂/PAA composite microgels with pH single response and MSN-S-S-CS with pH/redox co-responsive were prepared by graft modification on the surface.After synthesizing mesoporous silica and amination,a polyacrylic acid microgel?PAA?was synthesized on the surface by a free radical polymerization method to prepare a MSN-NH₂/PAA composite microgel.The MSN and its composites were characterized by XRD,FT-IR,BET and other characterization methods.The results show that the synthesized mesoporous silica belongs to the MCM-41 type,and its structure is a spherical structure with a diameter of about 100 nm.The release rate of MSN-NH₂/PAA loaded with 5-Amino Salicylic Acid?5-ASA?drug reached 68.9%under the condition of pH 8.4 of the large intestine solution,and only 15.9%under the condition of pH of the gastric juice of 1.2.The release rate of the drug at the pH of the intestinal juice was significantly higher than that of the gastric juice.Therefore,the MSN-NH_2/PAA composite microgel has pH responsiveness.In this experiment,the natural polymer compound chitosan?CS?was selected as the drug goalkeeper,and the pH/redox double responsive MSN-S-S-CS was prepared by3,3-dithiodipropionic acid linkage.Experiments show that MSN and MSN-S-S-CS are stable in ethanol solution,and MSN-S-S-CS has different swelling degree under pH and reduced glutathione?GSH?conditions.The drug release experiment showed that when the GSH concentration was 0.02 mM,the release rate was 21.5%,and when the 10 mM GSH solution was used,the release rate was 59.7%.When the pH was 1.2,the release rate was 38.9%.When the pH was increased to 7.4,the release rate was only 26.8%.Under the condition of pH 7.4 and GSH coexistence,the release rate was 45.2%,and at pH 1.2 and GSH coexistence,the release rate reached 67.1%.It can be seen that MSN-S-S-CS has certain responsive of GSH and pH,and the degree of GSH response alone is greater than the degree of pH response alone.There is a certain synergistic effect in the presence of both.