Quantitation of crystalline and amorphous forms of anhydrous neotame using 13C CPMAS NMR spectroscopy
| Autor: | Stephen A. Schroeder, Zedong Dong, Eric J. Munson, Jonathon S. Salsbury, Indra Prakash, Eric M. Gorman, Thomas J. Offerdahl, David J.W. Grant, Dewey H. Barich |
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| Rok vydání: | 2005 |
| Předmět: |
Carbon Isotopes
Magnetic Resonance Spectroscopy Calorimetry Differential Scanning Molecular Structure Analytical chemistry Pharmaceutical Science Dipeptides Nuclear magnetic resonance spectroscopy Carbon-13 NMR Amorphous solid chemistry.chemical_compound Solid-state nuclear magnetic resonance Polymorphism (materials science) chemistry Sweetening Agents Neotame Anhydrous Physical chemistry Chemical stability Crystallization |
| Zdroj: | Journal of Pharmaceutical Sciences. 94:2591-2605 |
| ISSN: | 0022-3549 |
| DOI: | 10.1002/jps.20469 |
| Popis: | Although most drugs are formulated in the crystalline state, amorphous or other crystalline forms are often generated during the formulation process. The presence of other forms can dramatically affect the physical and chemical stability of the drug. The identification and quantitation of different forms of a drug is a significant analytical challenge, especially in a formulated product. The ability of solid-state 13 C NMR spectroscopy with cross polarization (CP) and magic-angle spinning (MAS) to quantify the amounts of three of the multiple crystalline and amorphous forms of the artificial sweetener neotame is described. It was possible to quantify, in a mixture of two anhydrous polymorphic forms of neotame, the amount of each polymorph within 1–2%. In mixtures of amorphous and crystalline forms of neotame, the amorphous content could be determined within 5%. It was found that the crystalline standards that were used to prepare the mixtures were not pure crystalline forms, but rather a mixture of crystalline and amorphous forms. The effect of amorphous content in the crystalline standards on the overall quantitation of the two crystalline polymorphic forms is discussed. The importance of differences in relaxation parameters and CP efficiencies on quantifying mixtures of different forms using solid-state NMR spectroscopy is also addressed. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association. |
| Databáze: | OpenAIRE |
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