Poly(vinyl alcohol) (PVA) microspheres were prepared by dispersion reticulation with glutaraldehyde and further aminated. These microspheres were firstly loaded with plasmid DNA by electrostatic interactions and then entrapped in cellulose acetate butyrate (CAB) microcapsules for gastric protection. The entrapped PVA microspheres do not have enough force by swelling to produce the rupture of CAB shell, therefore the resistance of microcapsules was weaken by incorporating different amount of the intelligent polymer N-isopropylacrylamide-co-methyl methacrylate-co-methacrylic acid (NIPAAm-co-MM-co-MA). This polymer is insoluble in gastric juice at pH=1.2 and 36 ºC, but quickly solubilized in intestinal fluids (pH=6.8 and pH=7.4). Therefore, DNA loaded PVA microspheres were not expelled in acidic media but were almost entirely discharged in small intestine or colon. The integrity of DNA after entrapment was tested by agarose gel electrophoresis indicating that no DNA degradation occurs during encapsulation. Free and loaded aminated PVA microspheres display good bioadhesive properties.
Cellulose acetate butyrate-pH/thermosensitive polymer microcapsules containing aminated poly(vinyl alcohol) microspheres for oral administration of DNA
BORTOLOTTI, Fabrizio;CORTESI, Rita;MENEGATTI, Enea
2007
Abstract
Poly(vinyl alcohol) (PVA) microspheres were prepared by dispersion reticulation with glutaraldehyde and further aminated. These microspheres were firstly loaded with plasmid DNA by electrostatic interactions and then entrapped in cellulose acetate butyrate (CAB) microcapsules for gastric protection. The entrapped PVA microspheres do not have enough force by swelling to produce the rupture of CAB shell, therefore the resistance of microcapsules was weaken by incorporating different amount of the intelligent polymer N-isopropylacrylamide-co-methyl methacrylate-co-methacrylic acid (NIPAAm-co-MM-co-MA). This polymer is insoluble in gastric juice at pH=1.2 and 36 ºC, but quickly solubilized in intestinal fluids (pH=6.8 and pH=7.4). Therefore, DNA loaded PVA microspheres were not expelled in acidic media but were almost entirely discharged in small intestine or colon. The integrity of DNA after entrapment was tested by agarose gel electrophoresis indicating that no DNA degradation occurs during encapsulation. Free and loaded aminated PVA microspheres display good bioadhesive properties.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
