Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Nanocapsule suspensions

The procedure chosen for the preparation of lipid complexes of AmB was nanoprecipitation. This procedure has been developed in our laboratory for a number of years and can be applied to the formulation of a number of different colloidal systems liposomes, microemulsions, polymeric nanoparticles (nanospheres and nanocapsules), complexes, and pure drug particles (14-16). Briefly, the substances of interest are dissolved in a solvent A and this solution is poured into a nonsolvent B of the substance that is miscible with the solvent A. As the solvent diffuses, the dissolved material is stranded as small particles, typically 100 to 400 nm in diameter. The solvent is usually an alcohol, acetone, or tetrahydrofuran and the nonsolvent A is usually water or aqueous buffer, with or without a hydrophilic surfactant to improve colloid stability after formation. Solvent A can be removed by evaporation under vacuum, which can also be used to concentrate the suspension. The concentration of the substance of interest in the organic solvent and the proportions of the two solvents are the main parameters influencing the final size of the particles. For liposomes, this method is similar to the ethanol injection technique proposed by Batzii and Korn in 1973 (17), which is however limited to 40 mM of lipids in ethanol and 10% of ethanol in final aqueous suspension. [Pg.95]

Schaffazick SR, Pohlman AR, Dalla-Costa T, Guterres SS. Freezedrying polymeric colloidal suspensions nanocapsules, nanospheres and nanodispersion. A comparative study. Eur ] Pharm Biopharm 2003 56(3) 501-505. [Pg.191]

Suspensions of liposomes, microspheres and microcapsules, and nanospheres and nanocapsules formed from a variety of polymers or proteins, as discussed in section 8.6.3 form a new class of pharmaceutical suspension in which physical stability is paramount. It is important that on injection these carrier systems do not aggregate, as this will change the effective size and the fate of the particles. The exception to this is the deliberate flocculation of latex particles administered to the eye, where aggregation leads to agglomerated... [Pg.254]

Figure 21.13. A) High power microscope image showing that polysaccharide nanoparticles selectively associate with primary human bone marrow stromal cells in a 3D cell suspensions (n=12). The alginate nanocapsule core is stained with a fluorescent dye (Cell Tracker Red) which in white transmitted light is blue. B) TEM image showing presence of nanocapsules (i) at the surface of a primary hBMSC cell membrane and (ii) internalized within vacuoles. The yellow arrows denote position of nanocapsules. Figure 21.13. A) High power microscope image showing that polysaccharide nanoparticles selectively associate with primary human bone marrow stromal cells in a 3D cell suspensions (n=12). The alginate nanocapsule core is stained with a fluorescent dye (Cell Tracker Red) which in white transmitted light is blue. B) TEM image showing presence of nanocapsules (i) at the surface of a primary hBMSC cell membrane and (ii) internalized within vacuoles. The yellow arrows denote position of nanocapsules.
Other work on polymerization in particulate form has included the preparation of polycyanoacrylate nanocapsules as potential lysomotropic carriers, the encapsulation of pancreatic islet cells in hydrogels, " suspension polymerization of glycidyl methacrylate-2-hydroxypropylene dimethacrylate copolymers as hydrophilic macroporous spheres for enzyme immobilization, and the synthesis of macro-porous hydrogels as potential haemoperfusion adsorbents. ... [Pg.359]

The stability of nanoparticle suspensions is an important factor, as it determines the efficacy of the nanocapsules used in drug delivery applications. The stability is determined by the balance between the attractive van der Waals force and repulsive electrostatic force caused by the double layer of the oppositely charged ions [64]. Attraction and aggregation of nanoparticles are due to induced dipole—dipole forces (London dispersion forces). Induced dipole force is a part of the van der Waals forces. These forces result from multipoles formed in molecules, caused by quanmm induced instantaneous polarization. The formation of instantaneous dipoles occurs, because the electrons in adjacent molecules redistribute due to their correlated movements. [Pg.275]

Bouchemal, K., Briangon, S., Fessi, H., Chevalier, Y., Bonnet, I. Perrier, E. (2006). Simultaneous emulsification and interfacial polycondensation for the preparation of colloidal suspensions of nanocapsules. Materials Science and Engineering C, 26, 472-480. [Pg.1328]


See other pages where Nanocapsule suspensions is mentioned: [Pg.995]    [Pg.995]    [Pg.226]    [Pg.226]    [Pg.10]    [Pg.226]    [Pg.226]    [Pg.38]    [Pg.332]    [Pg.332]    [Pg.52]    [Pg.363]    [Pg.560]    [Pg.995]    [Pg.845]    [Pg.144]    [Pg.34]    [Pg.811]    [Pg.285]    [Pg.29]    [Pg.274]    [Pg.843]    [Pg.3]    [Pg.442]    [Pg.138]    [Pg.166]    [Pg.251]    [Pg.281]    [Pg.1322]   
See also in sourсe #XX -- [ Pg.254 ]




SEARCH



© 2024 chempedia.info