Determination of pipecuronium bromide and its impurities in pharmaceutical preparation by high-performance liquid chromatography with coulometric electrode array detection

A sensitive and selective HPLC method with coulometric electrode array detection for the determination of pipecuronium bromide and its four impurities has been developed. The coulometric electrode array detection at increasing potentials from +300 to +900mV of the porous graphite electrode versus the palladium reference electrode was used. The limit of detection and quantitation for pipecuronium bromide was 8 and 25ngml(-1), respectively. This elaborate method for the simultaneous analysis of pipecuronium bromide and its impurities proved to be fast, precise, accurate, sensitive, and could be applied to analysis in substances and in pharmaceutical preparations.     

On linear functional equations modulo $${\mathbb {Z}}$$ Z

Aequationes mathematicae - In this paper, we consider the condition $$\sum _{i=0}^{n+1}\varphi _i(r_ix+q_iy)\in {\mathbb {Z}}$$ for real valued functions defined on a linear space V. We derive...     

Bioactive Components,Volatile Profile and In Vitro Antioxidative Properties of Taxus baccata L. Red Arils

This study aimed at assessing the composition of bioactive compounds, including ascorbic acid, carotenoids and polyphenols, the volatile compound profile and the antioxidant activity of red arils (RAs) of Taxus baccata L. grown in diverse locations in Poland. Among the carotenoids assayed in high quantities (3.3–5.42 μg/g), the lycopene content (2.55–4.1 μg/g) was remarkably higher than that in many cultivated fruits. Samples collected from three sites were distinguished by higher amounts of ascorbic acid (125 mg/100 g, on average) than those found in many cultivated berries. Phenylpropanoids quantitatively dominated among the four groups of phenolic compounds. Chromatographic separation enabled the detection of two phenylpropanoid acids: ferulic and p-coumaric. Irrespectively of the growth site, RAs contained substantial amounts of (-)-epicatechin (1080 μg/100 g, on average). A higher ability to scavenge DPPH^● and ABTS^●+ radicals was found in the hydrophilic fraction of RAs from two sites (Warsaw and Koszalin) compared with the other two sites. The volatile compound profile of RAs was dominated by alcohols, followed by ketones, esters and aldehydes. The presence of some volatiles was exclusively related to the specific growth site, which may be regarded as a valuable indicator. The combination of bioactive and volatile compounds and the fairly good antioxidant potential of RAs render them an attractive source for preparing functional foods.     

Iminosugar-ferrocene conjugates as potential anticancer agents

We prepared a series of new iminosugar-ferrocene hybrids displaying potent inhibition of fucosidase (bovine kidney) and inactivation of MDA-MB-231 breast cancer cells proliferation at low micromolar concentrations. The synthetic route brought to light an unprecedented isomerisation of a 2-ethanalylpyrrolidine.     

N-Skatyltryptamines—Dual 5-HT6R/D2R Ligands with Antipsychotic and Procognitive Potential

A series of N-skatyltryptamines was synthesized and their affinities for serotonin and dopamine receptors were determined. Compounds exhibited activity toward 5-HT_1A, 5-HT_2A, 5-HT₆, and D₂ receptors. Substitution patterns resulting in affinity/activity switches were identified and studied using homology modeling. Chosen hits were screened to determine their metabolism, permeability, hepatotoxicity, and CYP inhibition. Several D₂ receptor antagonists with additional 5-HT₆R antagonist and agonist properties were identified. The former combination resembled known antipsychotic agents, while the latter was particularly interesting due to the fact that it has not been studied before. Selective 5-HT₆R antagonists have been shown previously to produce procognitive and promnesic effects in several rodent models. Administration of 5-HT₆R agonists was more ambiguous—in naive animals, it did not alter memory or produce slight amnesic effects, while in rodent models of memory impairment, they ameliorated the condition just like antagonists. Using the identified hit compounds 15 and 18, we tried to sort out the difference between ligands exhibiting the D₂R antagonist function combined with 5-HT₆R agonism, and mixed D₂/5-HT₆R antagonists in murine models of psychosis.     

All‐Solid‐State Ion Selective and All‐Solid‐State Reference Electrodes

This paper is aiming to give a brief overview of recent research in the field of all‐solid‐state, internal solution free, ion‐selective electrodes and reference electrodes, employing conducting polymers or nano‐/microstructures as solid contacts beneath the polymeric, ion‐selective or reference membranes. The emphasis is on papers published in the last five years (after 2006). According to the papers published, poly(3‐octylthiophene) conducting polymer transducers offer highly reliable sensors for various applications, involving demanding analytical approaches and miniature sensors. On the other hand, the search for alternative materials continues: the sensors obtained by placing nano‐/microstructures (conducting polymers but also other materials, like, e.g., carbon nanotubes) underneath the receptor membrane are intensively tested. The recent years have also shown how useful the application of advanced instrumental methods is for the investigation of processes occurring within all‐solid‐state ion‐selective electrodes.     

Distinguishing between polymorphic forms of linezolid by solid-phase electronic and vibrational circular dichroism

For the first time two crystalline forms of the same compound (linezolid polymorphs) were investigated by means of the solid-phase ECD and VCD spectra. The ECD spectra show distinct differences and the band at 221 nm serves as a diagnostic one because it is present in form II but absent in form III. The VCD spectra strongly differ in the diagnostic carbonyl absorption range exhibiting two relatively strong bands of opposite signs.     

An assessment of various powdered baby formulas by conventional methods (DSC) or FT-IR spectroscopy

Milk components are assumed to be uniformly distributed in a concentrate whilst it is being dried. During milk powder production, these components are redistributed in the drying droplets and the powder surface composition is significantly different from that of the bulk of it. The objective of this article was to analyze and compare phase transitions of powdered baby formulas as well as to make a study of their FT-IR spectra. Food powders of different composition were tested by a differential scanning calorimeter (DSC, TA Instruments Q 200) with a normal pressure cell and a System 2000 spectrophotometer. Significant differences were observed in the shape of curves of the mixtures and the agglomerates. The observed phase transitions in powders depended on fat content. Characteristic peaks of melting lactose were observed in the curves of the powdered baby formulas. The IR spectra proved to be useful in determining adulteration of baby formulas. Both methods were complimentary during a thorough evaluation of these food powders.     

Expression of GD3 synthase modifies ganglioside profile and increases migration of MCF-7 breast cancer cells

B- and c-series of gangliosides are over-expressed in neuro-ectoderm-related cancers, including breast cancer. It has been shown that G_D3 ganglioside is over-expressed in about 50% of invasive ductal breast carcinoma and the G_D3 synthase (GD3S) gene displays higher expression among estrogen receptor (ER) negative breast tumors. We previously showed that GD3S expression in MDA-MB-231 breast cancer cells induces the expression of G_D2 and increased cell proliferation and migration via a G_D2-dependent activation of c-Met receptor. Here, we show that in ER-positive MCF-7 breast cancer cells, GD3S expression resulted in an increase of G_D1b, which was associated with a decrease of G_M1a and G_M2. Meanwhile, GD3S expressing MCF-7 cells exhibited an increased migration without any modification of proliferation rate. Therefore, GD3S expression can result in different modifications of both ganglioside profiles and cell phenotypes depending on breast cell types.     

Self‐assembly of long‐chain quaternary ammonium cations in a hybrid inorganic–organic material with one‐dimensional polymeric tribromidoplumbate(II)

catena‐Poly[benzyldecyldimethylammonium [plumbate(II)‐tri‐μ‐bromido]], {(C₁₉H₃₄N)[PbBr₃]}_n, crystallizes as an inorganic–organic hybrid following monoclinic space‐group symmetry P2₁/c. The structure consists of extended chains running along the [001] direction and built of [PbBr₃]⁻ units. These inorganic chains are separated by interdigitated ammonium cations which form hydrophilic layers through weak C—H...Br interactions. The architecture is essentialy the same as found for n‐alkylbenzyldimethylammonium bromides.