title: Enhanced resistance of polyelectrolyte multilayer microcapsules to pepsin erosion and release properties of encapsulated indomethacin.
abstract: Polyelectrolyte multilayer films were prepared through layer-by-layer (LbL) self-assembly using polysaccharide sodium alginate (ALG) and chitosan (CHI). After incubation in an enzyme pepsin solution, the multilayer film was partially destroyed as detected by the decrease in fluorescent intensity because of the enzymatic degradation of CHI. The enzymatic desorption was also observed from the microcapsule wall made of the ALG/CHI multilayer film directly deposited on indomethacin (IDM) microcrystals through LbL self-assembly. After pepsin erosion, the IDM release from the microcapsules monitored by UV absorbance was obviously accelerated because of desorption. To enhance the stability of the ALG/CHI multilayer film to the enzymatic erosion, some physical and chemical methods were established to increase film thickness or to cross-link the polysaccharides within the film. Increasing the layer number and raising the deposition temperature effectively slowed down the enzymatic desorption and release rate. Especially, increasing deposition temperature was more effective because of producing a more perfect structure in the ALG/CHI multilayer film. Cross-linking the neighboring layers of ALG and CHI with 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide in the ALG/CHI multilayer film significantly reduced the enzymatic desorption and release rate. Therefore, increasing deposition temperature and cross-linking neighboring layers are effective methods to protect the multilayer film fabricated using LbL assembly from the enzymatic erosion and to prolong the release of the encapsulated drug.
authors: Research Institute of Materials Science, South China University of Technology, Guangzhou 510640, China.
authors: Chaoyang
authors: C
authors: Wang
authors: Shiqu
authors: S
authors: Ye
authors: Lin
authors: L
authors: Dai
authors: Xinxing
authors: X
authors: Liu
authors: Zhen
authors: Z
authors: Tong
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000737:chemistry; D002214:Capsules; D048271:Chitosan / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000737:chemistry; D016503:Drug Delivery Systems; D004573:Electrolytes / Q000737:chemistry; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007213:Indomethacin / Q000008:administration & dosage* / Q000737:chemistry; D018625:Microscopy, Atomic Force; D010434:Pepsin A / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry
chemical_list: D000464:Alginates; D000894:Anti-Inflammatory Agents, Non-Steroidal; D002214:Capsules; D003692:Delayed-Action Preparations; D004573:Electrolytes; D006603:Hexuronic Acids; D011134:Polysaccharides; D020723:Glucuronic Acid; D048271:Chitosan; D010434:Pepsin A; D007213:Indomethacin