LC‐NMR has been applied to componential analysis of carotenoids in several foods, specifically, tomato juice, palm oil, and satsuma mandarin orange juice. The crude carotenoids extracted with organic solvent from these foodstuffs were analyzed after simple pre‐processing. Three, four, and two kinds of carotenoids were identified for tomato juice, palm oil, and satsuma mandarin orange, respectively, primarily by comparing their NMR spectra with those of pure standard.

Carbamazepine (CBZ), a widely used antiepileptic, is known to be sensitive to light. The aim of this study was to evaluate the photostabilities of three cocrystals of CBZ (CBZ–succinic acid (SUC), CBZ–saccharin (SAC) form I, and CBZ–SAC form II) illuminated with a D₆₅ fluorescent lamp compared with those of the conventional solid forms: CBZ polymorphs (forms I, II, and III). The order of discoloration determined using a colorimetric measurement was almost consistent with that of the degradation rates estimated using Fourier-transform infrared reflection–absorption spectroscopy, and these parameters of CBZ polymorphs increased in the order of form III, form I, and form II. CBZ–SUC and CBZ–SAC form I significantly suppressed the discoloration and degradation of CBZ compared with the raw CBZ, while CBZ–SAC form II facilitated the discoloration and degradation of CBZ. These results were supported by the results from the low-frequency Raman spectroscopy. The molecular mobility estimated using solid-state nuclear magnetic resonance ¹H spin–lattice relaxation time strongly correlated with the degradation rate constant, indicating that molecular mobility significantly decreased following the formation of CBZ–SUC and CBZ–SAC form I and resulted in higher photostability. Overall, CBZ–SUC and CBZ–SAC form I are photostable forms and cocrystallization was proven to be an effective approach to improving the photostability of a photolabile drug.

We aimed to synthesize novel liver X receptor (LXR) agonists with potent agonist activity and subtype selectivity. Our synthetic scheme started with naphthoquinone derivatives, such as menadione and 2,3-dichloro-1,4-naphthoquinone. We introduced different substituents into the naphthoquinone structures, including aniline, piperidine, pyrrolidine, and morpholine, in one or two steps, and thus, we produced 14 target compounds. All 14 synthetic ligands were tested to determine whether they mediated LXR-mediated transcriptional activity. We investigated the transcriptional activity of each compound with two types of receptors, LXRα and LXRβ. Among all 14 compounds, two showed weak LXRβ-agonist activity, and two others exhibited potent LXRα-agonist activity. We also performed docking studies to obtain a better understanding of the modes of compound binding to LXR at the atomic level. In conclusion, we successfully synthesized naphthoquinone derivatives that act as LXRα/β agonists and selective LXRα agonists.

To prove the presence of a hydrogen-deuterium (H-D) exchange reaction, (1)H- and (13)C-NMR spectra of warfarin were measured in solvents containing D(2)O and H(2)O. In D(2)O or D(2)O/dimethyl sulfoxide (DMSO)-d(6) solvent, signal pattern changes were observed on H12 and H11 as well as 14 methyl protons over time while no changes were observed on H(2)O or H(2)O/DMSO-d(6) solvent. The observed changes in the solvents containing D(2)O were concluded to be caused by the H-D exchange reaction on H12, the process of CH(2)-->CHD-->CD(2). MS spectroscopy also confirmed these H-D exchanges. The kinetics of this reaction were analyzed as the successive reaction, and the mechanism was also proposed.

Liquid chromatography-nuclear magnetic resonance (LC-NMR) is an innovative technique that connects nuclear magnetic resonance (NMR) with high-performance liquid chromatography (HPLC) online, and can offer not only one-dimensional (1-D) but also two dimensional (2-D) NMR spectra for the components se...