Quantitative NMR Analysis of Complex Mixtures Using CRAFT (Complete Reduction to Amplitude Frequency Table) Method

Scott, Anne; Tim, A. Smitka; David, J. Russell; Krish, Krishnamurthy

doi:10.2174/2213235x03666150226231519

Cited by 18 publications

(12 citation statements)

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“…Analysis based on the raw data, namely, the time-domain data, would provide uniform and even improved absolute quantitation of individual components in a mixture analysis. Such analysis has been recently reported for the quantitation of spent media components of mammalian cell cultures (Bradley et al, 2015) and may be adopted in the future in metabolism studies.…”

Section: Discussionmentioning

confidence: 99%

Comparison between Radioanalysis and 19F Nuclear Magnetic Resonance Spectroscopy in the Determination of Mass Balance, Metabolism, and Distribution of Pefloxacin

Katyayan

Czeskis

et al. 2017

Drug Metabolism and Disposition

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Mass balance and metabolism studies using radiolabeled substances are well recognized as an important part of the drug development process. In this study, we directly assessed the use of fluorine nuclear magnetic resonance (F NMR) to achieve quantitative mass balance, metabolism, and distribution information for fluorinated compounds, without the need for radiolabeled synthesis or study. As a test case, the disposition of pefloxacin, a fluoroquinolone antibiotic, was evaluated in rats using quantitative F NMR in parallel with a radiolabeled study. Urine, bile, and feces samples were collected over specific periods after oral administration of either 25 mg/kg [C]pefloxacin or 25 mg/kg pefloxacin and were subsequently profiled by radioactivity or F NMR, respectively. The percentage of dose excreted in each matrix was comparable between the two methods, with the total dose recovered by radioactivity andF NMR determined to be 86.8% and 81.8%, respectively. In addition, plasma samples were collected to determine the exposure of pefloxacin and its circulating metabolites. The plasma exposure of pefloxacin determined by F NMR was within 5% to that calculated by a validated liquid chromatography-tandem mass spectrometry bioanalytical method. By both methods, pefloxacin was identified as the major circulating entity, with pefloxacin glucuronide as the major circulating metabolite. Quantitative analysis of metabolites in excreta was generally comparable between the two methods. In selected tissues, both methods indicated that the parent drug accounted for most of the drug-related material. In summary, we have demonstrated thatF NMR can be used as an alternative method to conventional radiolabeled studies for compounds containing fluorine without the need for radiolabeled synthesis/study.

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Section: Discussionmentioning

confidence: 99%

Comparison between Radioanalysis and 19F Nuclear Magnetic Resonance Spectroscopy in the Determination of Mass Balance, Metabolism, and Distribution of Pefloxacin

Katyayan

Czeskis

et al. 2017

Drug Metabolism and Disposition

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“…Recent reports have shown that the direct analysis of time domain, or free induction decay (FID), data can overcome many of the subjective issues associated with quantitating FT data . Complete Reduction to Amplitude‐Frequency Table (CRAFT) is an approach to time‐domain analysis that uses Bayesian probability theory to extract frequency, amplitude, phase, and decay rate directly from a single FID or clustered FIDs using frequency ranges defined from regions of interest (ROIs) identified from the FT spectra . Using CRAFT to quantitate time‐domain data negates the need for the rigorous corrections required when integrating or peak fitting FT data, thus providing an objective and reproducible approach to data analysis.…”

Section: Introductionmentioning

confidence: 99%

Band‐selective excitation NMR spectroscopy and quantitative time‐domain analysis using Complete Reduction to Amplitude‐Frequency Table (CRAFT) to determine distribution coefficients during drug development

Soulsby

2019

Magnetic Reson in Chemistry

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A sensitive quantitative 1H NMR method for determining distribution or partition coefficients has been developed that is applicable to early drug discovery. After partitioning and equilibration, aliquots from each layer are analyzed using band‐selective excitation 1H NMR spectroscopy in regions that are free of 1‐octanol and water solvent signals. Signals are quantitated directly using CRAFT software, and their amplitudes are adjusted to correct for nonuniformity within the excitation band. Using this approach, the distribution coefficients for 20 drugs present at low concentrations were determined giving values that were in excellent agreement with literature values.

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“…Recently, Krishnamurthy published CRAFT (complete reduction to amplitude frequency table), as a processing technique that converts the raw FID data (i.e., time domain data) into a table of frequencies, amplitudes, decay rate constants, and phases. Initial applications of CRAFT were focused on the automated extraction of amplitudes of various resonances from the time domain data, thereby avoiding the ubiquitous phase and baseline correction necessary for the extraction of amplitude information from spectral domain. CRAFT analyses of FIDs require minimal or no apodization prior to extraction of the four parameters (frequency, amplitude, decay rate constant, and phase) of all “resolved” (defined as per the data sampling duration of the FID) resonances.…”

Section: Introductionmentioning

confidence: 99%

Application of CRAFT (complete reduction to amplitude frequency table) in nonuniformly sampled (NUS) 2D NMR data processing

Krishnamurthy¹,

Hari

2017

Magnetic Reson in Chemistry

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The recently published CRAFT (complete reduction to amplitude frequency table) technique converts the raw FID data (i.e., time domain data) into a table of frequencies, amplitudes, decay rate constants, and phases. It offers an alternate approach to decimate time-domain data, with minimal preprocessing step. It has been shown that application of CRAFT technique to process the t dimension of the 2D data significantly improved the detectable resolution by its ability to analyze without the use of ubiquitous apodization of extensively zero-filled data. It was noted earlier that CRAFT did not resolve sinusoids that were not already resolvable in time-domain (i.e., t max dependent resolution). We present a combined NUS-IST-CRAFT approach wherein the NUS acquisition technique (sparse sampling technique) increases the intrinsic resolution in time-domain (by increasing t max), IST fills the gap in the sparse sampling, and CRAFT processing extracts the information without loss due to any severe apodization. NUS and CRAFT are thus complementary techniques to improve intrinsic and usable resolution. We show that significant improvement can be achieved with this combination over conventional NUS-IST processing. With reasonable sensitivity, the models can be extended to significantly higher t max to generate an indirect-DEPT spectrum that rivals the direct observe counterpart.

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Quantitative NMR Analysis of Complex Mixtures Using CRAFT (Complete Reduction to Amplitude Frequency Table) Method

Cited by 18 publications

References 0 publications

Comparison between Radioanalysis and 19F Nuclear Magnetic Resonance Spectroscopy in the Determination of Mass Balance, Metabolism, and Distribution of Pefloxacin

Comparison between Radioanalysis and 19F Nuclear Magnetic Resonance Spectroscopy in the Determination of Mass Balance, Metabolism, and Distribution of Pefloxacin

Band‐selective excitation NMR spectroscopy and quantitative time‐domain analysis using Complete Reduction to Amplitude‐Frequency Table (CRAFT) to determine distribution coefficients during drug development

Application of CRAFT (complete reduction to amplitude frequency table) in nonuniformly sampled (NUS) 2D NMR data processing

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