γ- and δ-Lactams from the Leaves of Clausena lansium.

Eight new clausenamides, including three γ-lactams (1-3), four δ-lactams (4-7), and an amide (8), and seven known lactams, including compounds 9-11, which were purified from natural sources for the first time, were characterized from the leaves of Clausena lansium. Their structures were elucidated using spectroscopic methods, and the absolute configurations were determined using electronic circular dichroism and single-crystal X-ray diffraction analyses with Cu Kα radiation. Compound 2 (50 µM) protected 22.24% of cortical neurons against Aß25-35-induced cell death.

Green Analytical Method for Simultaneous Determination of Glucosamine and Calcium in Dietary Supplements by Capillary Electrophoresis with Capacitively Coupled Contactless Conductivity Detection.

The need for analytical methods that are fast, affordable, and ecologically friendly is expanding. Because of its low solvent consumption, minimal waste production, and speedy analysis, capillary electrophoresis is considered a "green" choice among analytical separation methods. With these "green" features, we have utilized the capillary electrophoresis method with capacitively coupled contactless conductivity detection (CE-C4D) to simultaneously determine glucosamine and Ca2+ in dietary supplements. The CE analysis was performed in fused silica capillaries (50 µm inner diameter, 40 cm total length, 30 cm effective length), and the analytical time was around 5 min. After optimization, the CE conditions for selective determination of glucosamine and Ca2+ were obtained, including a 10 mM tris (hydroxymethyl) aminomethane/acetic acid (Tris/Ace) buffer of pH 5.0 as the background electrolyte; separation voltage of 20 kV; and hydrodynamic injection (siphoning) at 25 cm height for 30 s. The method illustrated good linearity over the concentration range of 5.00 to 200 mg/L of for glucosamine (R 2 = 0.9994) and 1.00 to 100 mg/L for Ca2+ (R 2 = 0.9994). Under the optimum conditions, the detection limit of glucosamine was 1.00 mg/L, while that of Ca2+ was 0.05 mg/L. The validated method successfully analyzed glucosamine and Ca2+ in seven dietary supplement samples. The measured concentrations were generally in line with the values of label claims and with cross-checking data from reference methods (HPLC and ICP-OES).

Formulation and biopharmaceutical evaluation of bitter taste masking microparticles containing azithromycin loaded in dispersible tablets.

The objective of this study was to prepare and evaluate some physiochemical and biopharmaceutical properties of bitter taste masking microparticles containing azithromycin loaded in dispersible tablets. In the first stage of the study, the bitter taste masking microparticles were prepared by solvent evaporation and spray drying method. When compared to the bitter threshold (32.43µg/ml) of azithromycin (AZI), the microparticles using AZI:Eudragit L100=1:4 and having a size distribution of 45-212µm did significantly mask the bitter taste of AZI. Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance spectroscopy (1H NMR) proved that the taste masking of microparticles resulted from the intermolecular interaction of the amine group in AZI and the carbonyl group in Eudragit L100. Differential scanning calorimeter (DSC) analysis was used to display the amorphous state of AZI in microparticles. Images obtaining from optical microscopy and scanning electron microscopy (SEM) indicated the existence of microparticles in regular cube shape with many layers. In the second stage, dispersible tablets containing microparticles (DTs-MP) were prepared by direct compression technique. Stability study was conducted to screen pH modulators for DTs-MP, and a combination of alkali agents (CaCO3:NaH2PO4, 2:1) was added into DTs-MP to create microenvironment pH of 5.0-6.0 for the tablets. The disintegration time of optimum DTs-MP was 53±5.29s and strongly depended on the kinds of lubricant and diluent. The pharmacokinetic study in the rabbit model using liquid chromatography tandem mass spectrometry showed that the mean relative bioavailability (AUC) and mean maximum concentration (Cmax) of DTs-MP were improved by 2.19 and 2.02 times, respectively, compared to the reference product (Zithromax®, Pfizer).

Clinical screening of paraquat in plasma samples using capillary electrophoresis with contactless conductivity detection: Towards rapid diagnosis and therapeutic treatment of acute paraquat poisoning in Vietnam.

The employment of a purpose-made capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C4D) as a simple and cost-effective solution for clinical screening of paraquat in plasma samples for early-stage diagnosis of acute herbicide poisoning is reported. Paraquat was determined using an electrolyte composed of 10mM histidine adjusted to pH 4 with acetic acid. A detection limit of 0.5mg/L was achieved. Good agreement between results from CE-C4D and the confirmation method (HPLC-UV) was obtained, with relative errors for the two pairs of data better than 20% for 31 samples taken from paraquat-intoxicated patients. The results were used by medical doctors for identification and prognosis of acute paraquat poisoning cases. The objective of the work is the deployment of the developed approach in rural areas in Vietnam as a low-cost solution to reduce the mortality rate due to accidental or suicidal ingestion of paraquat.