Colloidal-encapsulated polymeric nanoparticles

To increase the bioavailabiUty of proteins and peptides is a major concern during oral absorption because of the low absorption and instability of proteins in the gastrointestinal tract (GIT). Colloidal-encapsulated polymeric nanoparticles are an important... 

Nanodelivery systems can be defined as colloidal particles below lOOOnm size, such as nanospheres, nanocapsules, micelles, liposomes, solid lipid nanoparticles, nanocrystals, etc. The drug can be dissolved, entrapped, encapsulated, or attached to a nanoparticle matrix. Polymeric nanoparticle is a collective term given for any type of polymer nanoparticle (Soppimath et al., 2001). Generally, two main strategies are employed for their preparation the dispersion of preformed polymers and the polymerization of monomers. Depending on the process used for the preparation of nanoparticles, nanospheres (matrix-type), or nanocapsules (reservoir-type) can be obtained (Couvreur, 2013 Fattal et al., 2012 Rao and Geckeler, 2011). 

Particulates are commonly classified into micro- and nanoparticles based on the size of the particles. Nanoparticles are colloidal particles ranging from 10 to 1,000 run, in which drag may be entrapped, encapsulated, and/or absorbed. Microparticulates are drag-containing small polymeric particles (erodible, non-erodible or ion-exchange resins) within the size of 1-10 /on, which are suspended in a liquid carrier medium. 

Nanoparticles Nanoparticles have been among the most widely studied particulate delivery systems over the past three decades. They are defined as submicrometer-sized polymeric colloidal particles ranging from 10 to 1000 nm in which the drug can be dissolved, entrapped, encapsulated, or adsorbed [206]. Depending on the preparation process, nanospheres or nanocapsules can be obtained. Nanospheres have a matrixlike structure where the drug can either be firmly adsorbed at the surface of the particle or be dispersed/dissolved in the matrix. Nanocapsules, on the other hand, consist of a polymer shell and a core, where the drug can either be dissolved in the inner core or be adsorbed onto the surface [207],... 

Bouanani F, Bendedouch D, Hemery P, et al. (2008) Encapsulation of montmorillonite in nanoparticles by miniemulsion polymerization. Colloid Surf A Physicochem Eng Asp... 

Nanoparticles are classified into two groups according to preparation techniques, which are nanocapsules and nanospheres (see Figure 11.3). Nanocapsules are vesicular systems enveloped with a polymeric membrane film. The active substances are encapsulated in the inner core. Nanocapsules consist of oily core and unilayer polymeric membrane or aqueous core and double layer polymeric membrane, called nanocapsule and polymersome, respectively. Nanospheres are matrix-type colloidal particles and they do not have an oily core, in contrast to nanocapsules. Nanoparticles can be prepared directly from cationic polymers such as chitosan, PEI or PLL. These cationic nanoparticles have been studied extensively for nucleic acid delivery in particular. 

Hannah DC, Yang J, Podsiadlo P, Chan MKY, Demortiere A, Gosztola DJ, Prakapenka VB, Schatz GC, Kortshagen U, Schaller RD (2012) On the origin of photoluminescence in silicon nanocrystals pressure-dependent structural and optical studies. Nano Lett 12 4200 205 Harun NA, Horrocks BR, Fulton DA (2011) A miniemulsion polymerization technique for encapsulation of silicon quantum dots in polymer nanoparticles. Nanoscale 3 4733-4741 Heinrich JL, Curtis CL, Credo GM, Kavanagh KL, Sailor MJ (1992) Luminescent colloidal silicon suspensions from porous silicon. Science 255 66-68 Heitmaim J, Mueller F, Zacharias M, Goesele U (2005) Silicon nanocrystals size matters. Adv Mater 17 795-803... 

Conducting polymer nanocomposites consist of a conducting polymer or copolymer having nanofiUers in the form of particulate (OD) or fiber (ID) or flake (2D) dispersed in the conducting polymer matrix. These may be of different shape, but at least one dimension must be in the nanoscale. Nanocomposites of conducting polymers have been prepared by various methods such as colloidal dispersions, electrochemical encapsulation, coating of inorganic polymers, in situ polymerization with nanoparticles and have opened new avenues for material synthesis. 

P.S. Singh, V.K. Aswal, Characterization of physical structure of silica nanoparticles encapsulated in polymeric structure of polyamide films. Journal of Colloid and Interface Science 52(i (2008) 176-185. 

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