Separation of Unprecedented Degradants of Domperidone by Ultra-Performance Convergence Chromatography and Their Structure Elucidation

Domperidone, a gastroprokinetic agent, is a common drug to treat emesis. It was subjected to acid, base-mediated hydrolysis, peroxide-mediated oxidation, photolysis and thermal degradation according to ICH guidelines to observe stability of the selected drug under the stress conditions. Although the drug is resistant to base hydrolysis, photolysis and thermal stressors, two degradants (DP-ISO1 and DP-ISO2) were formed in acid mediated hydrolysis. Oxidation with hydrogen peroxide also resulted in one product (DP-OX). All three degradants were isolated from the crude reaction mixture by preparative high-performance liquid chromatography and supercritical fluid chromatography. Structures of isolated compounds were unambiguously characterized as 5-chloro-1-(1-(3-(6-chloro-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)propyl)piperidin-4-yl)-1,3-dihydro-2H-benzo[d]imidazol-2-one (DP-ISO1), 5-chloro-1-(3-(4-(5-chloro-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)piperidin-1-yl)propyl)-1,3-dihydro-2H-benzo[d]imidazol-2-one (DP-ISO2), 4-(5-chloro-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)-1-(3-(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-1-yl)propyl)piperidine 1-oxide (DP-OX) by analysis of mass spectrometry, 1D and 2D nuclear magnetic resonance spectra. To the best of our knowledge, DP-ISO1 and DP-ISO2 are new and DP-OX was previously reported as domperidone impurity.

Evaluation of tolerance of tubers Solanum tuberosum to silicа nanoparticles

In recent years, researches on the impact of nanometals on the state of soil ecosystems, including silicon, which is known to have a positive effect on plants under stressful conditions, have become relevant. The aim of this study was to assess the biological effects of nanoparticles (NP) of SiO₂ on the plant Solanum tuberosum. Testing of biological activity of NP SiO₂ on potato tubers was carried out on the example of five concentrations of metal increasing exponentially (0.03, 0.09, 0.18, 0.21, and 0.36 g/kg of potatoes) and control (without processing of NP SiO₂). We have shown that on the 21st day of the experiment after tuber treatment, the average mass of tuber in concentrations 0.18 and 0.21 g/kg of NP SiO₂ increased by 6.6% and 2.2%, respectively; stimulation of root length by 27.8-21.0%, the length of sprouts increased to 55.3%, and at a concentration of 0.36 g/kg on the 14th and 45th days, there was a maximum accumulation of Si in different parts of the plants. Analysis of chlorophyll content in the sprouts Solanum tuberosum showed that concentrations of nanoform SiO₂ 0.03-0.21 g/kg chlorophyll were higher than control by 48.8% and content of carotenoids by 29.7%. According to the results of field studies, the maximum mass of potato stems and tubers was observed at concentrations of 0.09 g/kg and 0.18 g/kg NP SiO₂, which confirmed the absence of toxic properties of NP SiO₂. The absence of the toxic effect of the investigated range of concentrations of NP SiO₂ from 0.03 to 0.36 g/kg was also confirmed by electrophoretic mobility of plant DNA molecules after incubation with silicon nanoparticles in vitro.

Fast determination of codeine, orphenadrine, promethazine, scopolamine, tramadol, and paracetamol in pharmaceutical formulations by capillary electrophoresis

Paracetamol is an active ingredient commonly found in pharmaceutical formulations in combination with one of the following compounds: codeine, orphenadrine, promethazine, scopolamine, and tramadol. In this work, we propose a unique analytical method for determination of these active ingredients in pharmaceutical samples. The method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection. The separation was achieved on a fused silica capillary (50 cm total length, 40 cm effective length, and 50 μm id) using an optimized background electrolyte composed of 20 mmol/L β-alanine/4 mmol/L sodium chloride/4 μmol/L sodium hydroxide (pH 9.6). Each sample can be analyzed in a single run (≤2 min) and the limits of detection were 2.5, 0.62, 0.63, 2.5, 15, and 1.6 μmol/L for scopolamine, tramadol, orphenadrine, promethazine, codeine, and paracetamol, respectively. Recovery values for spiked samples were between 94 and 104%.