Encapsulation nanoencapsulation

Moreover, insulin-loaded PLA nanoparticles with high yields of encapsulation were produced by Elvassore and coworkers [61]. In this work, a homogeneous solution of protein and polymer is sprayed through a nozzle in a high-pressure vessel. In order to achieve nanoencapsulation, mixtures of dichloromethane (DCM) and dimethylsulfoxide (DMSO) were used to ensure the solubility of both the polymer and the protein. In Figure 9.9-3 a SEM image of the fine-particle powders produced is presented. 

While the hterature has demonstrated the viabihty of nanoencapsulation via miniemulsion technology, a great many issues remain. These include the use of surfactant systems to stabihze the solid colloidal particles and bring them into the monomer droplets, uniformity of encapsulation (a uniform [small] number of solid particles per polymer particle for a minimum number of polymer particles, not including the encapsulated sohd), and complete coverage of the solids by the resultant polymer coating. 

Preparations of liposomes via SCF processing are designated as critical fluid liposomes (CFLs). CFLs have successfully encapsulated hydrophobic drugs such as taxoids, camptothecins, doxorubicin, vincristine, and cisplatin. In addition, stable paclitaxel liposomes with a size of 150-250 nm were obtained. Aphios Co. s patent (US Patent 5,776,486) on Super-Fluids CFL describes a method that is useful for the nanoencapsulation of paclitaxel and campothecin in aqueous liposomal formulations called Taxosomes and Camposomes , respectively. 

Microencapsulation is a technique which, as its name suggests, involves the encapsulation of small particles of dmg, or solution of dmg, in a polymer film or coat. Microspheres, on the other hand, are solid but not necessarily homogenous particles which can entrap drug. Although the terms tend to be used interchangeably, we retain the distinction here. Microspheres can be prepared also by a variety of techniques which are briefly discussed in the section on nanoencapsulation below. 

Such microbeads (as small as several hundred nanometres) have been found in North America s Great Lakes [52]. Similarly, the potential uses of nanomaterials in prepared foods have raised health concerns. An example of such a potential new product is a smart food that would respond to an individual s nutritional needs by, for example, selectively releasing encapsulated vitamins. Such potential products have concerns because nanoencapsulated materials having sizes smaller than about 300 nm could move into unintended parts of the body, such as across a placental barrier. 

Nuclear applications of nanocapsules are related to the emitting physical properties of the encapsulated material. Emitted radiation can be electromagnetic of high energy (y), electrons or positrons (/3), alpha particles (" He nucleus), or fission products [67]. These emitters can be in themselves radioactive or can be activated by a nuclear reaction, usually a neutron capture. The particular advantage of carbon nanocapsules in nuclear applications is related to the protective characteristics that the carbon capsule confers to the interior product. Experiments on irradiation of fullerenes have shown that knocked carbon atoms from one cage are foimd in another fuUerene and even form dimers and trimers by a recoil-implantation mechanism [68]. The observed major damage of capsules in nanoencapsulated molybdenum irradiated in a nuclear reactor was produced by... 

All the above-mentioned studies demonstrate that nanoencapsulation into polymeric carriers could enhance the therapeutic effectiveness of natural agents such as EGCG in the prevention and treatment of complex diseases like cancer. Table 2 summarizes the cancers affected by nanoencapsulated EGCG and the polymeric carriers used for the encapsulation. 

Micro- and nanoencapsulation are particularly important methods for protecting bioactive agents. Encapsulation is a process by which active components are surrounded by a polymer shell, the final particle size being as small as a few microns. Polyesters are widely used to create these shells and are examined in more detail below. 

Polymers are particularly useful for encapsulation applications.The use of novel micro- and nanoencapsulation techniques can help to address the main problems of developing novel functional foods, as explained below ... 

There is now an increased interest in reducing the size of the encapsulates (from micro- to nano-) in order to minimize their possible impact on food texture and appearance. Reducing the size of encapsulates also creates some extra benefits for specific functional food applications, because of the greater specific surface of the particles generated (for instance, improved adhesion properties). Lipids, polysaccharides and proteins have mostly been used to generate nanoencapsulation systems. 

To solve these problems encapsulation techniques have been developed [12,13]. Micro- or nanoencapsulation can envelop protein/peptide drugs within a polymeric matrix in order to protect them from degradation and modulate the biological active release [14]. 

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