Direct, preparative enantioselective chromatography of propranolol hydrochloride and thioridazine hydrochloride using carbon dioxide-based mobile phases

In this paper, we describe the direct, preparative enantioselective chromatography of racemic (rac)-propranolol hydrochloride (HCI) and rac-thioridazine.HCl using Chiralpak AD chiral stationary phase and mobile phase systems containing carbon dioxide and methanol without the use of basic or acidic additives. Isolated fractions of propranolol.HCl were positively identified by mass spectrometry, Beilstein flame test, melting point, and chemical analysis to be HCI enantiomers of propranolol-HCl salts exhibited characteristic mass spectra peaks at 36 and 38 mass-to-charge ratio in the expected 3:1 isotopic ratio for the solute that were absent in the mass spectra for the free-base forms. To our knowledge, the direct, preparative enantioselective isolation of HCI enantiomeric salts of rac-propranolol and of rac-thioridazine have not been previously demonstrated and published.     

Synthesis of Nd-doped barium cerate proton conductor from oxalate coprecipitate precursor

The decomposition process of barium, cerium and neodymium oxalates in air was investigated by DTA-TG. Decomposition of an oxalate coprecipitate precursor and formation of barium cerate were examined in air, N₂ and CO₂ atmospheres, respectively, by employing DTA-TG and XRD. The results showed that, in air, cerium oxalate could easily be decomposed to CeO₂ below 350°C and Nd₂O₃ could be obtained at 670°C, while a high temperature of >1400°C was needed to obtain BaO. Although some amount of BaCeO₃ was formed at 500°C in air, at 650°C in N₂ and at 800°C in CO₂, single perovskite phase of BaCeO₃ could only be obtained at a much higher temperature.This work is supported by the National Natural Science Foundation of China under Grant No. 59372103. F. L. Chen is grateful to Danish International Development Assistance (Danida) and State Science and Technology Commission (SSTC) of China for offering this joint Ph. D. study at Materials Department, Risø National Laboratory. Dr. N. Bonanos at Risø National Laboratory is acknowledged for his constant interest and encouragement to this work. Special thanks are given to P. V. Jensen and T. R. Strauss for their experimental assistance.     

Flow-injection on-line oxidizing fluorimetry and solid phase extraction for determination of thioridazine hydrochloride in human plasma

A simple, sensitive and specific fluorimetric method has been developed for the determination of thioridazine hydrochloride in human plasma involving solid phase extraction (SPE). In a flow-injection system, thioridazine hydrochloride is on-line oxidized into a strongly fluorescent compound with a lead dioxide solid-phase reactor and the fluorescence intensity is measured with a fluorescence detector (λ_ex = 349 nm, λ_em = 429 nm). A comparison of plasma sample pretreatment between SPE procedure and precipitation method was made and the results showed that SPE procedure was better than precipitation method. Under the optimum conditions, the fluorescence intensity is proportional to the concentration of thioridazine hydrochloride in the range from 0.015 to 2.000 μg mL⁻¹. The detection limit is 5.5 ng mL⁻¹ of thioridazine hydrochloride and the relative standard deviation is 1.06%. This method has been applied to determination of thioridazine hydrochloride in real patients plasma samples with the results compared with those obtained by HPLC method.     

Features of the precipitation of pectin substances from the valves ofGossypium hirsutum

An effective agent for precipitating pectin substances from the valves of cotton bolls has been selected.Bukhara Technological Institute of the Food and Light Industries. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 202–206, March–April, 1997.     

Gas-liquid chromotographic determination of perazine, thioridazine and thioridazine metabolites in human plasma.

A gas-liquid chromatographic method for the detection of perazine, thioridazine and its major metabolites in human plasma is presented. Repeated extraction, an internal standard and a temperature program with flame ionization detection make possible accurate and reproducible results with patients on therapeutic doses of these drugs. Examples of chromatograms after extraction of plasma are given.     

Technology of the production of pectin substances from the fruit ofSorbus aucuparia

The optimum conditions for the isolation of pectin substances from a pulp of the European mountain ash freed from lipophilic substances have been studied, and the characteristics of the substances are given.     

Synthesis and physicochemical properties of the pectin complexes with Xymedon

Russian Chemical Bulletin - The formation of stable complexes of pectin polysaccharides with 1-(2-hydroxyethyl)-4,6- dimethyl-1,2-dihydropyrimidin-2-one (Xymedon drug) was shown by UV and IR...     

Plant pectin substances. Methods of isolating pectin substances

Information is given on methods of isolating plant pectin substances from various raw-material sources, and the conditions for obtaining high-quality pectin are discussed.     

Plant pectin substances. Methods of isolating pectin substances

Information is given on methods of isolating plant pectin substances from various raw-material sources, and the conditions for obtaining high-quality pectin are discussed.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 635–643, September–October, 1993.     

Reinforcing the membrane-mediated mechanism of action of the anti-tuberculosis candidate drug thioridazine with molecular simulations

Thioridazine is a well-known dopamine-antagonist drug with a wide range of pharmacological properties ranging from neuroleptic to antimicrobial and even anticancer activity. Thioridazine is a critical component of a promising multi-drug therapy against M. tuberculosis. Amongst the various proposed mechanisms of action, the cell membrane-mediated one is peculiarly tempting due to the distinctive feature of phenothiazine drug family to accumulate in selected body tissues. In this study, we employ long-scale molecular dynamics simulations to investigate the interactions of three different concentrations of thioridazine with zwitterionic and negatively charged model lipid membranes. Thioridazine partitions into the interfacial region of membranes and modifies their structural and dynamic properties, however dissimilarly so at the highest membrane-occurring concentration, that appears to be obtainable only for the negatively charged bilayer. We show that the origin of such changes is the drug induced decrease of the interfacial tension, which ultimately leads to the significant membrane expansion. Our findings support the hypothesis that the phenothiazines therapeutic activity may arise from the drug–membrane interactions, and reinforce the wider, emerging view of action of many small, bioactive compounds.     

Technology of the production of pectin substances from the fruit ofSorbus aucuparia

The optimum conditions for the isolation of pectin substances from a pulp of the European mountain ash freed from lipophilic substances have been studied, and the characteristics of the substances are given.Academician I. P. Pavlov Ryazan' Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 777–780, November–December, 1979.