Multiple-sample probe for solid-state NMR studies of pharmaceuticals.

Benjamin N Nelson; Loren J Schieber; Dewey H Barich; Joseph W Lubach; Thomas J Offerdahl; David H Lewis; John P Heinrich; Eric J Munson

doi:10.1016/j.ssnmr.2005.08.006

PubMed · 16246531

Multiple-sample probe for solid-state NMR studies of pharmaceuticals.

Benjamin N Nelson·Loren J Schieber·Dewey H Barich·Joseph W Lubach·Thomas J Offerdahl·David H Lewis·John P Heinrich·Eric J Munson

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Abstract

Solid-state NMR spectroscopy (SSNMR) is an extremely powerful technique for the analysis of pharmaceutical dosage forms. A major limitation of SSNMR is the number of samples that can be analyzed in a given period of time. A solid-state magic-angle spinning (MAS) probe that can simultaneously acquire up to seven SSNMR spectra is being developed to increase throughput/signal-to-noise ratios. A prototype probe incorporating two MAS modules has been developed and spectra of ibuprofen and aspirin have been acquired simultaneously. This version is limited to being a two-module probe due to large amounts of space required for the tuning elements located next to the MAS modules. A new probe design incorporating coaxial transmission lines and smaller MAS modules has been constructed. This probe allows for close proximity of the MAS modules (within 3 cm), adequate proton decoupling power (>50 kHz), and the capability of remote tuning and sample changing. Spectra of hexamethylbenzene (HMB) have been acquired and show signal-to-noise ratios comparable to existing SSNMR probes. Adamantane line widths are also comparable to conventional probe technology. Decoupling powers of 70 kHz have been achieved using a MAS module suitable for 3 cm spacing between modules. Remote tuning has also been achieved with this new coaxial transmission line design. This probe design can be easily scaled to incorporate multiple MAS modules, which is a limitation of the previous design. The number of modules that can be incorporated is only limited by the number of transmission lines that will fit in a cross-sectional diameter of the bore and the axial field length of the magnet.

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Complex Mixtures Equipment Design Equipment Failure Analysis Magnetic Resonance Spectroscopy Molecular Probe Techniques Pharmaceutical Preparations Reproducibility of Results Sensitivity and Specificity Transducers Evaluation Study Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S.

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Benjamin N Nelson, Loren J Schieber, Dewey H Barich, Joseph W Lubach, Thomas J Offerdahl, David H Lewis, John P Heinrich, Eric J Munson. 2005-10-24. Multiple-sample probe for solid-state NMR studies of pharmaceuticals.. https://doi.org/10.1016/j.ssnmr.2005.08.006

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