Nanodelivery system

Pirollo KF, Rait A, Zhou Q, Hwang SH, Dagata JA, Zon G, et al. Materializing the potential of small interfering RNA via a tumor-targeting nanodelivery system. Cancer Res 2007 67 2938-2943. 

The targetability of polymeric forms of nanodelivery systems to cancer cells and tumors can be achieved by adopting either of the following two approaches (i) passive targeting and (ii) active targeting [66]. 

All of the earlier mentioned passive approaches for targeting the polymeric forms of nanodelivery systems can be utilized to enhance a tumor-specific delivery of drugs. However, these approaches are rarely used as the predominant methodologies in current cancer therapies. The preferred and more routinely employed technique involves an active targeting of the polymeric forms of nanodelivery systems. 

These and other observations clearly demonstrate that active targeting enhances the overall accumulation of a polymeric nanodelivery system by the cancer cells, thereby increasing the amount of the applied dose to actually penetrate the cancer cells. This may in turn lead to a substantial increase in the cytotoxicity of the drug and thus to a more effective anticancer activity. 

P. Satturwar, G. Gaucher, M. C. Jones, A. Furtos and J. C. Leroux, Polymeric micelles for oral drug delivery. In A Lavasanifar and Arshady R (Ed.). Polymeric Micelles and Related Nanodelivery Systems, Kentus Books, London, in press, (2008). 

A nanodelivery system is defined as a nanostructured material that releases therapeutic substances in the body in an efficacious and safe way. The major advances of such systems are the possibility of controlling size, stmcture, and morphology to tailor a treatment directed to the specific medical need. In the biomaterials field, increasing attention is being given to nanostructured polymers such as hydrogels and nanoparticles (NPs) that are able to offer new possibilities to deliver, in situ, a wide range of molecules and cells with a more controlled and optimized kinetics of release. 

By the investigation of the survival and engraftment of exogenous stem cells after intratracheal injection in a murine model, it was supposed that the cells could be hindered by the physiologic barriers such as mucus and airway surface or alveolar liquid, especially for nanodelivery systems for treatment of airway diseases [85]. 

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). 

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