Indomethacin has been encapsulated with polyelectrolyte multilayers for controlled release. Gelatin and alginate were alternatively deposited on indomethacin microcrystals. The released amount of indomethacin from coated microcrystals in pH6. 8 phosphate buffer solution （PBS） was measured with a UV spectrophometer. The polyelectrolyte multilayer capsule thickness was proved to control the release rate. The effects of osmotic pressure existed during the release process of indomethacin from microcapsules coated by （gelatin/alginate） 4. 相似文献
The use of mechanically robust nanoporous alumina capsules, with highly uniform pores of 25 nm to 55 nm, for controled drug delivery is demonstrated. The nanoporous alumina capsules were fabricated by anodization of an aluminum tube, resulting in a highly uniform, large surface area, relatively inexpensive device suitable for biofiltration applications. Characterization of diffusion from the nanoporous capsules using fluorescein isothiocyanate and dextran conjugates of varying molecular weight, showed that molecular transport could be readily controlled by selection of capsule pore size. A branched membrane structure, with a stepwise change in pore size from large to small, is used to provide small pore-sized membranes with sufficient mechanical strength for handling. 相似文献
Composite hollow microspheres consisting of polyaniline (PANI) and indomethacin (IND) are prepared through a self‐assembly process in a mixed methanol/water solutions. Different volume fractions of methanol to water and different aniline concentrations are investigated to obtain the optimal conditions for the formation of PANI/IND composite hollow microspheres. The morphologies of the PANI/IND composites are characterized, showing the inner hollow center of the microspheres. Spectroscopic characterizations reveal that the synthesized materials have many typical features of chemically synthesized PANI and confirm the presence of IND in the composites. A controlled release of IND is achieved by adjusting the pH value of the buffer solution. 相似文献
Using ethyl acrylate and methyl methacrylate as hydrophobic monomers, a series of hydrophobic nanoparticle dispersions were prepared by one‐step polymerization (i.e., soap‐free batch emulsion polymerization). To obtain stable aqueous nanoparticle dispersions, a small amount of ionic comonomer, sodium 4‐ω‐acryloyloxy‐β‐hydroalkyl sulfonate (Cops‐1) was used. The nanoparticles were characterized by TEM, Zetasizer and DSC. It was found that number average diameter ( ) values range from 144 to 202 nm at 25 °C, and the diameter distribution ( ) from 1.11 to 1.14. These results indicate that the nanoparticles show a narrow distribution of sizes. Zeta potentials of the obtained nanoparticles are in range of ?38.8 to ?29.7 mV at 25 °C. This suggests that they can be well dispersed in water. Using salicylic acid (SA) as model drug molecules, a novel swelling method was developed for loading SA into the nanoparticles in an aqueous dispersion state, and both related loading processes and controlled release behavior were investigated. It was found that the nanoparticles can sustain SA release, and compared to different types of nanoparticles, PMMA nanoparticles can retard SA release more effectively.
