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Letermovir is a cytomegalovirus inhibitor for cytomegalovirus infection a hematopoietic-cell transplantation. In the degradation test of Letermovir, five new impurities were detected at levels of ND ∼ 2.21 % (by oxide, thermal or photolytic). These impurities were synthesized directly, characterized and identified by HRMS NMR spectra and X-ray crystallography. Then co-injected with commercial products to confirm their retention times in HPLC. The possible formation pathways and synthetic methods of these impurities were discussed in details. Furthermore, the toxicological properties of impurities were evaluated by ACD/Percepta 14.52.0 (Build 3525) software. • Five new impurities were characterized and identified. • The possible formation pathways and synthetic methods of these impurities were discussed. • X-ray crystal structure of Imp P salt with diisopropylamine was obtained. [ABSTRACT FROM AUTHOR]

• Two novel pharmaceutical salts of letermovir (LM) were successfully achieved. • This is the first report of a single crystal structure of LM, which could contribute to the development of corresponding drugs. • Salt 1 and salt 2 showed better solubility and stability under wet conditions, and had the potential to replace the bulk drug. Two novel pharmaceutical salts of letermovir (LM) were successfully achieved by a slow reaction in solution containing LM with ethylenediamine (EDA) and diisopropylamine (DIPA). In this article, crystal structure, X-ray diffraction, thermal properties, 1H NMR, 13C NMR, HPLC analysis, stability and solubility of salt 1 and salt 2 have been discussed. Salt 1 crystalized in R 3 space group and salt 2 crystalized in P 3 2 21 space group. The formation of salt was proved by p K a rule and single crystal determination. From the perspective of crystal structure, for salt 1 and salt 2 , the strong hydrogen bond makes the crystal structure more stable. The weak interaction between molecules is further studied by Hirshfeld surface and 2D-fingerprint plots. Notably, this is the first report of a single crystal structure of LM, which could contribute to the development of corresponding drugs. In addition, salt 1 and salt 2 showed better solubility and stability under wet conditions, and had the potential to replace the bulk drug. Two novel pharmaceutical salts of letermovir (LM) were successfully synthesized. [Display omitted] [ABSTRACT FROM AUTHOR]

We present detailed ophthalmic findings in a case of tuberculum sellae meningioma with acute visual symptoms due to optic canal involvement. A 62-year-old Japanese woman reported a 1-week history of headaches and blurred vision in her left eye. Her visual acuity was 0.3 in the left eye with no ophthalmoscopic abnormalities. A relative afferent pupillary defect and inferior temporal field defect were found in the left eye. Pattern visual evoked potentials were undetectable in the left eye. Enhanced magnetic resonance imaging showed a 9 mm intracranial lesion around the left optic nerve anterior to the chiasm. She was diagnosed with granulomatous inflammation because of the increased cell counts and protein concentration in the cerebrospinal fluid. She was treated with steroid pulse therapy, and her visual acuity and visual field defect improved to normal in 3 weeks. However, 16 months after the onset, she suffered from headaches again and had a complete loss of vision in her left eye. There was no response to steroid pulse therapy. Enhanced magnetic resonance imaging revealed that the lesion had extended into the left optic canal, and emergency tumor removal surgery was carried out. The histopathological diagnosis was meningioma. One month after the surgery, her left visual acuity improved to 1.2, and her visual field was almost normal. Pattern visual evoked potentials were present but had a prolonged P100 latency of 170 ms. A thinning of the ganglion cell complex was detected by optical coherence tomography. Ophthalmologists should be aware that a small tuberculum sellae meningioma can cause acute visual symptoms due to optic canal involvement. Early consultation with a neurosurgeon is necessary. Visual evoked potentials and optical coherence tomography are sensitive and helpful in following patients with optic nerve compression. [ABSTRACT FROM AUTHOR]

In this work, novel stationary phase coatings by zeolite SiO 2 NPs coupled with β-cyclodextrin (β-CD) or β-CD/L-phenylalanine were developed for chiral open-tubular capillary electrochromatography (OT-CEC). The OT columns were prepared taking advantage of the strong adhesion of polydopamine in one-step method. Scanning electron micrography and electroosmotic flow were used to characterize the prepared single/dual-selector OT columns. Chiral separation of four chiral analytes (catechin/epicatechin, ephedrine/pseudoephedrine, ritodrine and salbutamol) was carried out in order to evaluate the performance of the prepared columns in OT-CEC with amperometric detection system. In terms of migration time, peak area, resolution, and selectivity factor of catechin/epicatechin and salbutamol, the run-to-run, day-to-day, and column-to-column repeatability were within 8.9%. Under the optimum conditions, the developed methods were applied for the analyses of Chinese herbal medicine Catechu herbs and salbutamol aerosol samples. [ABSTRACT FROM AUTHOR]

Novel open-tubular (OT) columns were prepared for the first time based on zeolite silica nanoparticles (SiO2NPs) as the nano coating materials. The main immobilization factors, including the size and concentration of zeolite SiO2NPs, the content of bovine serum albumin (BSA), heat temperature and time, were investigated to obtain OT columns with good stability and repeatability. Then, the separation performance of the prepared OT columns with/without BSA modifier was explored using capillary electrochromatography with an amperometric detection system. Under the optimum conditions, eight groups of model molecules, including homologues, structural isomers, epimers and enantiomers, underwent baseline separation in the prepared OT columns. The zeolite SiO2NPs-OT columns provided an efficiency of up to 108 200 plates m−1 for 4-chloro-2-methylaniline, and the OT column modified with BSA accomplished the separation and analysis of ephedrine and pseudoephedrine in ephedra herbs. The relative standard deviations of the migration time, peak area and resolution of the selected model analytes were within 8.4% for run-to-run, day-to-day, and column-to-column repeatability. Furthermore, the prepared OT columns could provide acceptable separation performance in a simple running buffer without any organic additives or surfactants, indicating their promising potential for isomer separation. [ABSTRACT FROM AUTHOR]