An exploratory study of drug concentration and inhibitory effect of cetylpyridinium chloride buccal tablets on SARS-CoV-2 infection among 10 Chinese subjects.

BACKGROUND: It was evidenced that cetylpyridinium-chloride (CPC) mouthwash could inhibit SARS-COV-2 activity and reduce salivary viral load, thus reducing SARS-CoV-2 transmission. However, due to insufficient residence time in the oral cavity, CPC-containing mouthwashes have no prolonged antiviral effect. The duration of action of the CPC buccal tablet is expected to be longer than that of the mouthwash. However, there are currently no reports on the salivary drug concentration of CPC buccal tablets. OBJECTIVE: The study aimed to investigate the salivary drug concentration of CPC buccal tablets and the antiviral effect of CPC on SARS-CoV-2 in vitro. TRIAL DESIGN: This is a single-dose, single-arm clinical trial, involving 10 Chinese healthy subjects who received 2-mg CPC buccal tablet to collect saliva samples and to detect saliva concentration at different timepoints within 2 h (Clinical Trial Registration Number: NCT05802628, Registration Date: April 6, 2023). MATERIALS AND METHODS: CPC concentration in saliva was detected by liquid chromatography tandem mass spectrometry (LC-MS/MS), and pharmacokinetic parameters were calculated based on the non-compartmental model. With an in vitro antiviral experiment, the activity of CPC buccal tablets against SARS-CoV-2 and its cellular toxicity was tested. RESULTS: Drug concentrations in saliva at 15 min, 30 min, 1 h, 1.5 h, and 2 h after administration were 8008.33 (1042.25, 41081.11), 2093.34 (373.15, 5759.83), 1016.58 (378.66, 3480.68), 891.77 (375.66, 6322.07), and 717.43 (197.87, 2152.71) ng/mL. PK parameters of saliva concentration: Cmax = 8008.33 (1042.25, 41081.11) ng/mL, AUC0-t = 4172.37 (904.42, 13912.61) ng/mL * h, AUC0-∞ = 6712.85 (1856.77, 19971.12) ng/mL * h, T1/2 = 1.22 (0.59, 2.83) h, Tmax = 0.25 (0.25, 0.25) h. As determined in in vitro experiment, CPC was active on SARS-CoV-2 with cytotoxic and inhibitory activity of CC50 = 35.75 µM (≈12155 ng/mL) and EC50 = 7.39 µM (≈2512.6 ng/mL). CONCLUSIONS: The comparison between the salivary CPC concentration and EC50/CC50 values from in vitro antiviral experiments suggests that CPC buccal tablets may inhibit SARS-CoV-2 activity, and the inhibition may last for approximately 30 min without cytotoxicity.

An Unsymmetric Salamo-like Chemosensor for Fuorescent Recognition of Zn2.

A new unsymmetric tetradentate salamo-like chemical sensor H2L for fluorescent recognition of Zn2+ has been designed and synthesized. The sensor can recognize Zn2+ from other metal ions examined with selectivity, anti-interference, reliability and high sensitivity (LOD = 1.89 × 10-6 M) in ethanol/H2O solution. The results of UV-Vis and fluorescent spectra analyses, X-ray crystallographic study and DMol3 simulation and calculation (on Materials Studio) indicate that the chelation-enhanced fluorescence (CHEF) recognition mechanism of the sensor H2L for Zn2+ is of its hindered PET process. The sensor H2L for Zn2+ has excellent fluorescence characteristics and has potential application value in biological and environmental systems.

Reinforced carbon fiber laminates with oriented carbon nanotube epoxy nanocomposites: Magnetic field assisted alignment and cryogenic temperature mechanical properties.

The epoxy nanocomposites with ordered multi-walled carbon nanotubes (MWCNTs) were used to influence the micro-cracks resistance of carbon fiber reinforced epoxy (CF/EP) laminate at 77 K, Oxidized MWCNTs functionalized with Fe3O4 (Fe3O4/O-MWCNTs) with good magnetic properties were prepared by co-precipitation method and used to modify epoxy (EP) for cryogenic applications. Fe3O4/O-MWCNTs reinforced carbon fiber epoxy composites were also prepared through vacuum-assisted resin transfer molding (VARTM). The ordered Fe3O4/O-MWCNTs were observed to have effectively improved the mechanical properties of epoxy (EP) matrix at 77 K and reduce the coefficient of thermal expansion (CTE) of EP matrix. The ordered Fe3O4/O-MWCNTs also obviously improved the micro-cracks resistance of CF/EP composites at 77 K. Compared to neat EP, the CTE of ordered Fe3O4/O-MWCNTs modified CF/EP composites was decreased 37.6%. Compared to CF/EP composites, the micro-cracks density of ordered Fe3O4/O-MWCNTs modified CF/EP composites at 77 K was decreased 37.2%.

Preparation and Characterization of Ni Spines Grown on the Surface of Cubic Boron Nitride Grains by Electroplating Method.

Cubic boron nitride (cBN) is widely applied in cutting and grinding tools. cBN grains plated by pure Ni and Ni/SiC composite were produced under the same conditions from an additive-free nickel Watts type bath. The processed electroplating products were characterized by the techniques of scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermoanalysis (TG-DTA). Due to the presence of SiC particles, there are some additional nodules on the surface of Ni/SiC plated cBN compared with the pure Ni plated cBN. The unique morphology of Ni/SiC plated cBN should attain greater retention force in resin bond. Moreover, the coating weight of cBN grains could be controlled by regulating the plating time. cBN grains with 60% coating weight possess the optimum grinding performance due to their roughest and spiniest surface. In addition, Ni spines plated cBN grains show good thermal stability when temperature is lower than 464 °C. Therefore, the plated cBN grains are more stable and suitable for making resin bond abrasive tools below 225 °C. Finally, the formation mechanism of electroplating products is also discussed.