Analysis of a Nanocrystalline Polymer Dispersion of Ebselen Using Solid-State NMR, Raman Microscopy, and Powder X-ray Diffraction

作者：Vogt Frederick G^*; Williams Glenn R

来源：Pharmaceutical Research, 2012, 29(7): 1866-1881.

DOI：10.1007/s11095-012-0713-9

• confocal Raman microscopy
• dipolar spin diffusion
• nanocrystalline polymer dispersion
• powder X-ray diffraction
• solid-state NMR

Nanocrystalline drug-polymer dispersions are of significant interest in pharmaceutical delivery. The purpose of this work is to demonstrate the applicability of methods based on two-dimensional (2D) and multinuclear solid-state NMR (SSNMR) to a novel nanocrystalline pharmaceutical dispersion of ebselen with polyvinylpyrrolidone-vinyl acetate (PVP-VA), after initial characterization with other techniques.
A nanocrystalline dispersion of ebselen with PVP-VA was prepared and characterized by powder X-ray diffraction (PXRD), confocal Raman microscopy and mapping, and differential scanning calorimetry (DSC), and then subjected to detailed 1D and 2D SSNMR analysis involving H-1, C-13, and Se-77 isotopes and H-1 spin diffusion.
PXRD was used to show that dispersion contains nanocrystalline ebselen in the 35-60 nm size range. Confocal Raman microscopy and spectral mapping were able to detect regions where short-range interactions may occur between ebselen and PVP-VA. Spin diffusion effects were analyzed using 2D SSNMR experiments and are able to directly detect interactions between ebselen and the surrounding PVP-VA.
The methods used here, particularly the 2D SSNMR methods based on spin diffusion, provided detailed structural information about a nanocrystalline polymer dispersion of ebselen, and should be useful in other studies of these types of materials.

• 出版日期2012-7