Results found: 3

Number of results on page

Search results

Search:
in the keywords: porous silicon

Sort By:

Limit search:

On the mechanism of electroluminescence emission by porous silicon layers

100%

Velasco J.

Open Chemistry

2005

vol. 3

issue 3

470-481

The analytical treatment of a model considering the electrooxidation of p-porous silicon layers under galvanostatic conditions is able to give account of experimental facts such as the shape and location of the electroluminescence peak as well as of the spectral shift of the electroluminescence peak produced by oxidation. The proposed model considers electroluminescence to be the result of electron injection into the conduction band by an adsorbed intermediate produced by electrooxidation of the surface coverage with hydrogen or siloxene of the silicon nanocrystallites. The access of holes to the surface is made possible by low accumulation layer conditions and is the rate determining step in the electroluminescence mechanism. In this way it is possible to give a satisfactory explanation to the shift towards the blue experimented by the electroluminiscence emission maximum as a consequence of electrooxidation.

Celecoxib confinement within mesoporous silicon for enhanced oral bioavailability

88%

Wang F., Barnes T. J., Prestidge C. A.

Mesoporous Biomaterials

2014

vol. 1

issue 1

We investigate the physicochemical characteristics of celecoxib (CEL) entrapped within particles of an oxidized porous silicon matrix (pSiox); determine the oral dose response of CEL compared to pure drug and innovator formulation; develop in vivo-in vitro correlation (IVIVC). CEL was loaded into a pSiox matrix by solvent partitioning, with the physical state of the CEL characterized by FTIR, DSC, TGA and XRD, and correlated with in vitro dissolution behavior. Single dose pharmacokinetic parameters of orally dosed CEL were determined in fasted rats for aqueous suspensions of pure CEL, Celebrexr and CEL-pSiox microparticles. Physicochemical testing of CEL-pSiox formulation confirmed the entrapment of CEL within porous nanostructure in an amorphous or non-crystalline form. CEL-pSiox demonstrated superior pharmacokinetics compared with CEL particles or Celebrexr, i.e. increased absolute bioavailability (96.2% vs. 65.2% vs. 88.1%), increased Cmax (0.91 ± 0.09 μg/mL vs. 0.50 ± 0.16 μg/mL vs. 0.73 ± 0.23 μg/mL) and reduced Tmax (1.0 ± 0.0 h vs. 2.8 ± 0.8 h vs. 3.4 ± 1.0 h). Single point correlation was established between in vitro dissolution efficiency (% DE) and in vivo absolute bioavailability or Cmax . Porous silicon microparticles can be formulated as an effective orally dosed solid dispersion preparation for celecoxib

Desorption/ionization on silicon for small molecules: a promising alternative to MALDI TOF.

63%

Kraj A., Dylag T., Gorecka-Drzazga A., Bargiel S., Dziuban J., Silberring J.

Acta Biochimica Polonica

2003

vol. 50

issue 3

783-787

A method has been developed for laser desorption/ionization of catecholamines from porous silicon. This methodology is particularly attractive for analysis of small molecules. MALDI TOF mass spectrometry, although a very sensitive technique, utilizes matrices that need to be mixed with the sample prior to their analysis. Each matrix produces its own background, particularly in the low-molecular mass region. Therefore, detection and identification of molecules below 400 Da can be difficult. Desorption/ionization of samples deposited on porous silicon does not require addition of a matrix, thus, spectra in the low-molecular mass region can be clearly readable. Here, we describe a method for the analysis of catecholamines. While MALDI TOF is superior for proteomics/peptidomics, desorption/ionization from porous silicon can extend the operating range of a mass spectrometer for studies on metabolomics (small organic molecules and their metabolites, such as chemical neurotransmitters, prostaglandins, steroids, etc.).

Refine search results

1 Acta Biochimica Polonica

1 Mesoporous Biomaterials

1 Open Chemistry

1 2014

1 2005

1 2003

1 Bargiel S.

1 Barnes T. J.

1 Dylag T.

1 Dziuban J.

1 Gorecka-Drzazga A.

1 Kraj A.

1 Prestidge C. A.

1 Silberring J.

1 Velasco J.

1 Wang F.

Search results

On the mechanism of electroluminescence emission by porous silicon layers

Celecoxib confinement within mesoporous silicon for enhanced oral bioavailability

Desorption/ionization on silicon for small molecules: a promising alternative to MALDI TOF.