Drug porous silicon particles

Sarparanta M, Makila E, Heikkila T, Salonen J, Kukk E, Lehto V-P, Santos HA, Hirvonen J, Airaksinen AJ (2011) F-Labeled modified porous silicon particles for investigation of drug delivery carrier distribution in vivo with positron emission tomography. Mol Pharm 8(5) 1799-1806... 

Thermally carbonized Human epithelial colorectal adenocarcinoma cell lines Caco-2, HT-29 Hydrophobin Class II protein conjugated to porous sihcon particles. Cell viabihty maintained and still able to allow drug permeation from the porous silicon particle to the cells Bimbo et al. (2012)... 

Foraker et al. 2003). In the paper, Foraker et al. used microfabricated porous silicon particles to enhance insulin permeabihty across Caco-2 cell monolayer, which is commonly used in vitro model of the human small intestinal mucosa to predict the absorption of orally administrated drugs. They observed that the flux of insulin across the cell monolayer was approximately 50-fold compared with liquid formulations and nearly 10-fold higher compared with liquid formulations with permeation enhancer, if insulin was loaded in PSi. 

With the aim of developing a drug delivery vehicle, hydrosilylated and thermally oxidized porous silicon microparticles were injected into the vitreous of rabbit eyes (Cheng et al. 2008). It was noted that the particles settled into the inferior vitreous cavity over a few days. Degradation of the hydrosilylated particles took considerable time (>4 months) in comparison to untreated particles which degraded within a period of 3 weeks. No adverse effects were observed in ocular tissues including the retina and the lens. Furthermore, normal ocular pressure was maintained. 

Wu EC, Andrew JS, Cheng L, Freeman WR, Pearson L, Sailor MJ (2011b) Real-time monitoring of sustained drug release using the optical properties of porous silicon photonic crystal particles. Biomaterials 32 1957-1966... 

Wu EC, Andrew JS, Cheng LY, Freeman WR, Pearson L, Sailor MJ (2011) Real-time monitoring of sustained drug release using the optical properties of porous silicon photonic crystal particles. Biomaterials 32(7) 1957-1966. doi 10.1016/j.biomaterials.2010.11.013 Yu L (2001) Amorphous pharmaceutical solids preparation, characterization and stabilization. Adv Drug Deliv Rev 48(l) 27-42. doi 10.1016/s0169-409x(01)00098-9... 

Electroencapsulation is an application of electrospraying in which liquid is atomized into micro- or even nanosized droplets using electrostatic forces alone. The method allows better controllability of the capsulation process than, e.g., the most commonly used spray drying. Due to the applied electrostatic forces, it also enables production of complex capsule structures, like solid shell covered liquid core particles. In this review, we will focus on electroencapsulation processes used to improve the handling, processing, and administration of porous silicon-based drug delivery systems. 

Porosifying controlled areas of a silicon wafer enables porous silicon to be integrated with silicon circuitry or MEMS devices within chip-based products. Although porous sihcon particles (microparticles and nanoparticles) can be derived from anodized wafers (see handbook chapters Milling of Porous Silicon Microparticles and Photoluminescent Nanoparticle Derivatization Via Porous Silicon ), this route is only viable for low-volume high-value product areas, as in some medical therapy applications (see handbook chapter Drug Delivery with Porous Silicon ). 

Bottom-up strategies, which employ silicate precursors, such as tetraethoxysi-lane (TEOS), produce porous silicon dioxide. Silicon dioxide is a much more chemically stable interface than silicon, and precludes some forms of surface functionalization, such as carbonization, which is used to tune particle properties. Additionally, bottom-up approaches are hmited to the production of either spherical or ellipsoid particles, unless used in conjunction with top-down lithography. Shape has been shown fundamentally to determine several properties of the particle that are relevant for drug deUvery, such as flow dynamics, margination, degradation rate and cell uptake [21, 22]. For these reasons, top-down approaches to the production of pSi for biomedical applications have been historically favored. 

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