Publications by authors named "Ai Kohama"
Article Synopsis
- P-NMR is easier to analyze than H-NMR, making it simpler to identify target signals for quantitation.
- The study presents a method for determining the purity of brigatinib (BR), an organophosphorus compound, using quantitative P-NMR (P-qNMR) across multiple labs.
- Results showed that the purity of BR was 97.94 ± 0.69% with P-qNMR, closely matching the 97.26 ± 0.71% found using H-qNMR, suggesting P-qNMR is a viable alternative for measuring organophosphorus compounds.
Quantitative P-NMR for Purity Determination of Sofosbuvir and Method Validation.
Chem Pharm Bull (Tokyo)
December 2022
Article Synopsis
- The study examines the effectiveness of phosphorus quantitative NMR (P-qNMR) for measuring the purity of the drug sofosbuvir (SOF), as it offers clearer signals compared to hydrogen quantitative NMR (H-qNMR).
- Soxfabuvir's purity was found to be 100.63% via P-qNMR and 99.07% via H-qNMR using methanol-d, highlighting numerical discrepancies likely due to overlapping signals in H-qNMR.
- When switching to dimethyl sulfoxide-d (DMSO-d) as a solvent, P-qNMR yielded a SOF purity of 99.10%, which aligns closely with H
Recently, quantitative NMR (qNMR), especially H-qNMR, has been widely used to determine the absolute quantitative value of organic molecules. We previously reported an optimal and reproducible sample preparation method for H-qNMR. In the present study, we focused on a P-qNMR absolute determination method.
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- Quantitative NMR (qNMR) is used to establish the absolute quantitative value of standards for HPLC-based quantification, specifically for hygroscopic substances like saikosaponin a and indocyanine green (ICG).
- The study highlights the impact of humidity on the purity determination of ICG, noting that non-controlled humidity resulted in higher variation (86.12 ± 2.70%) and residual ethanol in the samples.
- Using a controlled humidity environment, the purity of ICG decreased variability (84.19 ± 0.47%), and employing a constant temperature and humidity box minimized variation further (82.26 ± 0.19%), suggesting its use for standard reference preparation in JP
A 70-year-old man presented with sudden onset of global aphasia and right hemiplegia. Brain MRI revealed occlusion of the left middle cerebral artery. He was diagnosed as having a hyperacute cerebral infarction.
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