Solid-state nuclear magnetic resonance applications

In the following, some examples of applications of Fourier transform infrared (FTIR) Spectroscopy and of solid-state nuclear magnetic resonance (NMR) to the study of polymorphism in polymers are described. 

DE Bugay. Solid-state nuclear magnetic resonance spectroscopy Theory and pharmaceutical applications. Pharm Res 10(30) 317-327, 1993. 

Byrn SE, Bugay DE, Tishmack PA. Solid state nuclear magnetic resonance spectroscopy—pharmaceutical applications. J Pharm Sci 2003 92(3) 441-474. 

The purpose of this article is to review the progress of solid-state nuclear magnetic resonance over the last 4 years (ca. May 1995-May 1999) and is written as a sequel to our previous review.1 As in that review, the emphasis will be placed on the methodological developments. Nevertheless, the applications of the technical advances, particularly those that are significant to chemistry, biochemistry, biology and materials science, will also be mentioned. 

All the powerful methods of magnetic resonance, from solid-state nuclear magnetic resonance (NMR) to medical magnetic resonance imaging, depend on measuring the time evolution of a spin system following the application of one or more radio frequency pulses. In the visible and ultraviolet, ultrafast optical pulse sequences have been used for many years to measure both population dynamics and coherence phenomena. At low... 

Wu, G. (1998) Recent developments in solid-state nuclear magnetic resonance of quadrupolar nuclei and applications to biological systems, Biochemistry and Cell Biology, 76, 429-442. 

Plasticisers are added to PVC to achieve flexibility and workability. The flexibility or softness is determined by the type of plasticiser and level used in relation to the PVC (phr). They also operate as an internal lubricant between the PVC molecules. Based on organic esters, e.g., phthalates, adipates, trimellitates, phosphates, etc., addition levels can be as low as 20 phr for semi-rigid to 100 phr for very flexible applications. The effect on the thermal stability significantly depends on the physical state of the PVC-plasticiser system (260). The relative amount of crystalline PVC in PVC/diethylhexyl phthalate has been identified on the basis of a combination of carbon-13 solution and solid state nuclear magnetic resonance (NMR) (361). 

One technique that is becoming increasingly important for the characterization of materials is that of solid-state nuclear magnetic resonance (NMR) spectroscopy, and the application of this methodology to topics of pharmaceutical interest has been amply demonstrated.The NMR spectra of polymorphs or solvatomorphs often contains non-equivalent resonance peaks for analogous nuclei since the intimate details of the molecular environments associated with differing crystal structures can lead to perturbations in nuclear resonance energies. 

Solid-state nuclear magnetic resonance (SSNMR) spectroscopy is a powerful technique used in the analysis of solids, and is currently finding more and more applications, particularly in the analysis of pharmaceutical formulations. It is a non-destructive, non-invasive technique that can be employed to simultaneously examine the physical and chemical states of both the active pharmaceutical ingredient (API) and the excipients present as they exist within the formulation. It is also highly selective, as nuclei of the API often have different chemical shifts than do common excipients. 

Duer MJ (ed) (2002) Solid-state nuclear magnetic resonance spectroscopy, principles and applications. Blackwell Science, Oxford... 

Tishmack, P.A. Bugay, D.E. Byrn, S.R. Solid-state nuclear magnetic resonance spectroscopy— pharmaceutical applications. J. Pharm. Sci. 2003, 92, 441-474. 

Y Aboul-Enein. Applications of solid-state nuclear magnetic resonance spectroscopy to pharmaceutical research. Spectroscopy 5 32-33, 1990. 

R 598 L. K. Thompson, Unraveling the Secrets of Alzheimer s j3-Amyloid Fibrils , P. Natl. Acad. Sci. U. S. A., 2003,100, 383 R 599 T. Timusk, The Mysterious Pseudogap in High Temperature Superconductors An Infrared View , Solid State Commun., 2003,127, 337 R 600 P. A. Tishmack, D. E. Bugay and S. R. Byrn, Solid-State Nuclear Magnetic Resonance Spectroscopy - Pharmaceutical Applications , J. Pharm. Sci., 2003, 92,441... 

R 651 Y. -h. Fang, Principles of High Resolution Solid-State Nuclear Magnetic Resonance and Its Application in Research of Cement Chemistry , Jianzhu Cailiao Xuebao, 2003,6, 54... 

Freude, D. Quadrupolar Nuclei in Solid-state Nuclear Magnetic Resonance. In Encyclopedia of Analytical Chemistry. Applications, Theory and... 

Solid-state nuclear magnetic resonance (ssNMR) spectroscopy has emerged over the years as a powerful analytical method in solid-state chemistry, especially with the advancements in techniques that allow the acquisition of high-resolution spectra [47]. In the broadest sense, ssNMR is mostly applied in characterization of crystalline materials as a means to support PXRD structural analyses by providing information on the number of molecules in the asymmetric unit or the symmetry of the occupied positions within the unit cell. Another major field of application is the structural characterization of amorphous and disordered solids where standard X-ray diffraction-based techniques fail to give detailed structural information. When discussing ssNMR in the context of API polymorphism and synthesis of co-crystals,... 

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