We report a study of encapsulation and release from polymeric micro- and nano-particles of the antiischemic drug N6-cyclopentyladenosine (CPA) and bovine serum albumin (BSA). Classical preparation methods of the particles (nanoprecipitation, single or double emulsion/solvent evaporation) are compared with those obtained by their formulation with a novel method, employing a thermosensible gel of Pluronic F-127, whose aqueous solutions can be liquid when refrigerated, but gel upon warming. CPA-loaded nanoparticles obtained by classical methods drastically reduce their drug content and the ability to control its release. The novel method allows us to obtain, instead, CPA encapsulation values in nanoparticles similar to those obtained for microparticles, achieving also a control of the drug release. Any drastic reduction of BSA particle content is observed by decreasing their size from micro- to nano-scales, independently on the employment of classical or novel preparation methods. Moreover, the size reduction induces only a weak increase of the BSA release rate. The patterns of protein released from micro- and nano-particles obtained by the same formulation method are similar: the micro- and nano-spheres prepared by double emulsion technique show an incomplete BSA release, characterized by an elevated burst effect followed by a very slow phase; the release from micro- and nano-particles obtained by the novel method is complete and quite regular, being characterized by a little burst release followed by a fast phase. The results can be related to the strong BSA distribution in the surface or in the core of microparticles (observed by confocal laser scanning microscope) obtained by the classical or novel methods, respectively.

New formulation strategies of nanoparticles for the controlled relase of drugs with small or large molecuar weight

SCATTURIN, Angelo;DALPIAZ, Alessandro
2006

Abstract

We report a study of encapsulation and release from polymeric micro- and nano-particles of the antiischemic drug N6-cyclopentyladenosine (CPA) and bovine serum albumin (BSA). Classical preparation methods of the particles (nanoprecipitation, single or double emulsion/solvent evaporation) are compared with those obtained by their formulation with a novel method, employing a thermosensible gel of Pluronic F-127, whose aqueous solutions can be liquid when refrigerated, but gel upon warming. CPA-loaded nanoparticles obtained by classical methods drastically reduce their drug content and the ability to control its release. The novel method allows us to obtain, instead, CPA encapsulation values in nanoparticles similar to those obtained for microparticles, achieving also a control of the drug release. Any drastic reduction of BSA particle content is observed by decreasing their size from micro- to nano-scales, independently on the employment of classical or novel preparation methods. Moreover, the size reduction induces only a weak increase of the BSA release rate. The patterns of protein released from micro- and nano-particles obtained by the same formulation method are similar: the micro- and nano-spheres prepared by double emulsion technique show an incomplete BSA release, characterized by an elevated burst effect followed by a very slow phase; the release from micro- and nano-particles obtained by the novel method is complete and quite regular, being characterized by a little burst release followed by a fast phase. The results can be related to the strong BSA distribution in the surface or in the core of microparticles (observed by confocal laser scanning microscope) obtained by the classical or novel methods, respectively.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/497825
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