An improved experiment for heteronuclear-correlation 2D NMR in Solids

Burum, D. P.; Bielecki, Anthony

doi:10.1016/0022-2364(91)90155-m

Cited by 50 publications

(66 citation statements)

References 3 publications

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“…Since the correlation peaks are observed by utilizing dipolar coupling-driven magnetization transfer in the HETCOR method, the peak intensity correlates mainly with the distance between the nuclei and therefore it is expected that the method can provide a great deal of the configurational information. 8,10) Although the cross peaks of directly bound C-H pairs were observed in the HETCOR spectrum of the complex with natural abundance, no signals related to intermolecular interaction were observed unambiguously. Therefore the samples prepared using [ 13 C-19]-benzoic acid were measured instead, on the assumption that the carboxyl group most probably interacted with the other group and the enriched carboxyl carbon would enhance the intensity of signals relevant to interaction including the long-range signals.…”

Section: Resultsmentioning

confidence: 95%

“…7,8) Powdered sample (400-500 mg) was packed into a 7-mmf zirconia rotor with a Kel-F cap and was rotated at 5 kHz. The spinning speed was set to 3-5 kHz in most HETCOR experiments, because of a good compromise between the need to suppress the 13 C spinning sidebands and the requirement for CRAMPS that the rotor speed be slow to strengthen peak intensity.…”

Section: Methodsmentioning

confidence: 99%

“…The spinning speed was set to 3-5 kHz in most HETCOR experiments, because of a good compromise between the need to suppress the 13 C spinning sidebands and the requirement for CRAMPS that the rotor speed be slow to strengthen peak intensity. 8) In this experiment the spinning speed was set to 5 kHz to avoid a overlap of significant correlation peaks with spinning side bands. In the t 1 period ( 1 H dimension) 64-128 points and in the t 2 period ( 13 C dimension) 1584 points were acquired, and the spectra were zero-filled to a final size of 128ϫ1024.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, 2D heteronuclear-correlation (HETCOR) method is expected to provide still more information about the geometry of molecules than 1D proton or carbon solidstate NMR does. 7,8) Since the heteronuclear dipolar coupling just depends on the distance between the nuclei, the correlated peak intensity of HETCOR spectrum correlate mainly with the distance of nuclei. [8][9][10] Therefore 1D and 2D solidstate NMR can be one of powerful methods for investigation of intermolecular interaction in formulation.…”

mentioning

confidence: 99%

“…7,8) Since the heteronuclear dipolar coupling just depends on the distance between the nuclei, the correlated peak intensity of HETCOR spectrum correlate mainly with the distance of nuclei. [8][9][10] Therefore 1D and 2D solidstate NMR can be one of powerful methods for investigation of intermolecular interaction in formulation. In order to verify the usefulness of the solid-state NMR technique for the interaction study, we measured 1D 13 C CP/MAS NMR and 2D HETCOR spectra of the molecular complex of tryptamine and benzoic acid, found by Koshima et al, 11,12) as a model sample.…”

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confidence: 99%

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Investigation of Intermolecular Interaction in Molecular Complex of Tryptamine and Benzoic Acid by Solid-State 2D NMR

Terakita

Matsunaga

Ueda

et al. 2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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In the course of drug development, it is a great concern to understand an intermolecular interaction, such as hydrogen bonding and electrostatic interaction, between an active ingredient and excipients in a drug formulation, because the interaction may affect the physicochemical properties of the formulation, such as polymorphism, 1) chemical reactivity, 2,3) and dissolution.4) The influence of the interaction can be either preferable to the quality of formulation or not. 3,4) Therefore there is possibility to design drug formulation for better quality by utilizing or avoiding the intermolecular interaction intentionally. For such an intentional formulation design, the compatibility testing with various combinations of components is usually necessary to investigate whether an active ingredient interacts with any excipients or not, and reveal the mechanism and influence of the interaction on the quality if any. Although the analytical method such as powder X-ray diffraction (PXRD) and IR could be often used for such a research, it would be difficult to evaluate the interaction in drug formulation containing some components since the coexistent matrix would complicate the results.Recently the solid-state NMR technique has been commonly used for research on the drug conformation as represented by polymorphism studies. 1,5,6) In the conformational study for drug formulation, solid-state NMR has intrinsic advantages as follows: 1) This method is less destructive so that the sample probably remains in the original conformation. 2) It is more possible to avoid the interference of coexistent excipients with evaluation because some chemical shifts of an active ingredient, which mostly has some unsaturated bonds, likely separate from those of excipients used commonly for solid dosage form, many of which have no unsaturated bonds. In addition, 2D heteronuclear-correlation (HETCOR) method is expected to provide still more information about the geometry of molecules than 1D proton or carbon solidstate NMR does. 7,8) Since the heteronuclear dipolar coupling just depends on the distance between the nuclei, the correlated peak intensity of HETCOR spectrum correlate mainly with the distance of nuclei.8-10) Therefore 1D and 2D solidstate NMR can be one of powerful methods for investigation of intermolecular interaction in formulation. In order to verify the usefulness of the solid-state NMR technique for the interaction study, we measured 1D 13 C CP/MAS NMR and 2D HETCOR spectra of the molecular complex of tryptamine and benzoic acid, found by Koshima et al.,11,12) as a model sample. Although the crystal structure of the complex has not been determined, the complex was predicted to have hydrogen bonding and/or electrostatic interaction from the results of X-ray crystallographic analysis for other analogous complexes. Since such interactions could be generated in drug formulation and its structure was unknown, it was selected as a model sample. ExperimentalMaterials Tryptamine was purchased from Tokyo Kasei Kogyo Co., Ltd. Benzoic...

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Section: Resultsmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Investigation of Intermolecular Interaction in Molecular Complex of Tryptamine and Benzoic Acid by Solid-State 2D NMR

Terakita

Matsunaga

Ueda

et al. 2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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Molecular Motions in the Supramolecular Complexes between Poly(ɛ-caprolactone)-Poly(ethylene oxide)-Poly(ɛ-caprolactone) andα- andγ-Cyclodextrins

Mirau²,

Shin

et al. 2002

Macromol. Chem. Phys.

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Nuclear Magnetic Resonance, Solid State in Analysis of Polymers and Rubbers

Mirau¹

2000

Encyclopedia of Analytical Chemistry

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Solid‐state nuclear magnetic resonance (NMR) has emerged as one of the premier methods for polymer characterization in the solid‐state. High‐resolution spectra can be obtained with cross‐polarization and magic‐angle sample spinning using equipment that is commonly available on modern NMR spectrometers. Information about the chain structure, conformation, dynamics, intermolecular interactions and the morphology can be obtained by measuring the chemical shifts, line shapes and relaxation times. New experiments have been developed to filter the NMR response such that the spectrum from aparticular component can be measured. The resolution has been increased with the development of multidimensional NMR methods for measuring the structure and dynamics. Solid‐state NMR experiments can provide the link between the chemical structure and the macroscopic properties of polymers.

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An improved experiment for heteronuclear-correlation 2D NMR in Solids

Cited by 50 publications

References 3 publications

Investigation of Intermolecular Interaction in Molecular Complex of Tryptamine and Benzoic Acid by Solid-State 2D NMR

Investigation of Intermolecular Interaction in Molecular Complex of Tryptamine and Benzoic Acid by Solid-State 2D NMR

Molecular Motions in the Supramolecular Complexes between Poly(ɛ-caprolactone)-Poly(ethylene oxide)-Poly(ɛ-caprolactone) andα- andγ-Cyclodextrins

Nuclear Magnetic Resonance, Solid State in Analysis of Polymers and Rubbers

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