Organic Cations (organic + cation)

Distribution by Scientific Domains

Terms modified by Organic Cations

  • organic cation transporter

  • Selected Abstracts


    ChemInform Abstract: Two Novel Copper,Undecaniobates Decorated by Copper,Organic Cations [{Cu(H2O) L}2{CuNb11O35H4}]5- (L: 10-Phenanthroline, 2,2,-Bipyridine) Consisting of Plenary and Monolacunary Lindqvist-Type Isopolyniobate Fragments.

    CHEMINFORM, Issue 40 2010
    Jing-Yang Niu
    Abstract Compounds (III) and (IV) represent the first examples of copper undecaniobates. [source]


    No pharmacokinetic interaction between paliperidone extended-release tablets and trimethoprim in healthy subjects,

    HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 7 2009
    An Thyssen
    Abstract Objective The effect of trimethoprim, a potent organic cation transport inhibitor, on the pharmacokinetics (PK) of paliperidone extended-release tablets (paliperidone ER), an organic cation mainly eliminated via renal excretion, was assessed. Methods Open-label, two-period, randomized, crossover study in 30 healthy males. Single dose of paliperidone ER 6,mg was administered either alone on day 1 or day 5 during an 8-day treatment period of trimethoprim 200,mg twice daily. Serial blood and urine samples were collected for PK and plasma protein binding of paliperidone and its enantiomers. The 90% confidence interval (CI) of ratios with/without trimethoprim for PK parameters of paliperidone and its enantiomers calculated. Results Creatinine clearance decreased from 119 to 102,mL,min,1 with trimethoprim. Addition of trimethoprim increased unbound fraction of paliperidone by 16%, renal clearance by 13%, AUC, by 9%, and t by 19%. The 90% CIs for ratios with/without trimethoprim were within the 80,125% range for Cmax, AUClast, and renal clearance. For AUC,, 90% CI was 79.37,101.51, marginally below the lower bound of the acceptance range. Paliperidone did not affect steady-state plasma concentrations of trimethoprim. Conclusions No clinically important drug interactions are expected when paliperidone ER is administered with organic cation transport inhibitors. Copyright 2009 John Wiley & Sons, Ltd. [source]


    Novel Potentiometric Sensors of Molecular Imprinted Polymers for Specific Binding of Chlormequat

    ELECTROANALYSIS, Issue 2 2008
    Ayman
    Abstract Molecularly imprinted polymers (MIP) were used as potentiometric sensors for the selective recognition and determination of chlormequat (CMQ). They were produced after radical polymerization of 4-vinyl pyridine (4-VP) or methacrylic acid (MAA) monomers in the presence of a cross-linker. CMQ was used as template. Similar non-imprinted (NI) polymers (NIP) were produced by removing the template from reaction media. The effect of kind and amount of MIP or NIP sensors on the potentiometric behavior was investigated. Main analytical features were evaluated in steady and flow modes of operation. The sensor MIP/4-VP exhibited the best performance, presenting fast near-Nernstian response for CMQ over the concentration range 6.210,6,1.010,2,mol L,1 with detection limits of 4.110,6,mol L,1. The sensor was independent from the pH of test solutions in the range 5,10. Potentiometric selectivity coefficients of the proposed sensors were evaluated over several inorganic and organic cations. Results pointed out a good selectivity to CMQ. The sensor was applied to the potentiometric determination of CMQ in commercial phytopharmaceuticals and spiked water samples. Recoveries ranged 96 to 108.5%. [source]


    Expression of organic cation transporters OCT1 (SLC22A1) and OCT3 (SLC22A3) is affected by genetic factors and cholestasis in human liver,

    HEPATOLOGY, Issue 4 2009
    Anne T. Nies
    An important function of hepatocytes is the biotransformation and elimination of various drugs, many of which are organic cations and are taken up by organic cation transporters (OCTs) of the solute carrier family 22 (SLC22). Because interindividual variability of OCT expression may affect response to cationic drugs such as metformin, we systematically investigated genetic and nongenetic factors of OCT1/SLC22A1 and OCT3/SLC22A3 expression in human liver. OCT1 and OCT3 expression (messenger RNA [mRNA], protein) was analyzed in liver tissue samples from 150 Caucasian subjects. Hepatic OCTs were localized by way of immunofluorescence microscopy. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and genome-wide single-nucleotide polymorphism microarray technology served to genotype 92 variants in the SLC22A1-A3/OCT1-3 gene cluster. Transport of metformin by recombinant human OCT1 and OCT3 was compared using transfected cells. OCT1 mRNA and protein expression varied 113- and 83-fold, respectively; OCT3 mRNA expression varied 27-fold. OCT1 transcript levels were on average 15-fold higher compared with OCT3. We localized the OCT3 protein to the basolateral hepatocyte membrane and identified metformin as an OCT3 substrate. OCT1 and OCT3 expression are independent of age and sex but were significantly reduced in liver donors diagnosed as cholestatic (P , 0.01). Several haplotypes for OCT1 and OCT3 were identified. Multivariate analysis adjusted for multiple testing showed that only the OCT1-Arg61Cys variant (rs12208357) strongly correlated with decreased OCT1 protein expression (P < 0.0001), and four variants in OCT3 (rs2292334, rs2048327, rs1810126, rs3088442) were associated with reduced OCT3 mRNA levels (P = 0.03). Conclusion: We identified cholestasis and genetic variants as critical determinants for considerable interindividual variability of hepatic OCT1 and OCT3 expression. This indicates consequences for hepatic elimination of and response to OCT substrates such as metformin. (HEPATOLOGY 2009.) [source]


    A survey of the behavior of the hydroxybisphosphonic function in crystallized acids, metallic salts, and some related compounds

    HETEROATOM CHEMISTRY, Issue 2 2001
    J.-P. Silvestre
    The flexibility and the different degrees of ionization of the hydroxybisphosphonic function provide numerous possibilities for the complexation of metallic and organic cations to molecules possessing these functions. The properties of this class of compounds are very interesting for different industrial and medical applications. They depend in a large part on the nature of the hydrocarbonated chain substituted to CH3 in hydroxyethylidenebisphosphonic acid and of the number and the position of the bisphosphonic groups grafted on this chain. 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:73,89, 2001 [source]


    The polymine spermine regulates osteogenic differentiation in adipose stem cells,

    JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 5a 2008
    G.S. Tjabringa
    Abstract For bone tissue engineering, it is important that mesenchymal stem cells (MSCs) differentiate into osteoblasts. To develop a method for differentiation of adipose tissue-derived mesenchymal stem cells (AT-MSCs) along the osteogenic lineage, we studied the effect of polyamines, which are organic cations implicated in bone growth and development, on differentiation of AT-MSCs. Treatment of goat-derived AT-MSCs with 1,25-dihydroxyvitamin-D3 (1,25(OH)2D3), which stimulates osteogenic differentiation, for 7 days induced gene expression of the polyamine-modulated transcription factor-1 (PMF-1) and spermidine/spermine N (1)-acetyltransferase (SSAT), which are both involved in polyamine metabolism, suggesting that polyamines are involved in osteogenic differentiation of AT-MSCs. Furthermore, treatment of AT-MSCs with the polyamine spermine-regulated gene expression of runx-2, a transcription factor involved in early stages of osteogenic differentiation, and that of osteopontin, a bone matrix protein expressed in later stages of osteogenic differentiation. Runx-2 gene expression was increased 4 and 14 days after a short 30 min. treatment with spermine, while osteopontin gene expression was only increased 4 days after spermine treatment. Finally, alkaline phosphatase activity, which is intimately involved in the formation of extracellular matrix of bone, was increased 4 weeks after the 30 min.-spermine treatment of AT-MSCs. In conclusion, this study shows for the first time that the polyamine spermine regulates differentiation of AT-MSCs along the osteogenic lineage, which can be used as a new method for differentiation of AT-MSCs along the osteogenic lineage. Therefore, polyamines may constitute a promising tool for bone tissue engineering approaches using AT-MSCs, such as a one-step surgical procedure for spinal interbody fusion. [source]


    Uptake of lamivudine by rat renal brush border membrane vesicles

    JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2002
    Takatoshi Takubo
    Uptake of lamivudine, a nucleoside analogue antiviral agent, by brush border membrane vesicles (BBMV) prepared from rat renal cortex was investigated. Initial uptake of lamivudine by BBMV was stimulated in the presence of an outward pH gradient. Determination of the kinetic parameters of the initial uptake yielded apparent Km and Vmax values of 2.28 mM and 1.56 nmol (mg protein),1 (20 s),1, respectively. The pH-driven uptake of lamivudine was inhibited by organic cations such as trimethoprim and cimetidine. The inhibitory effect of trimethoprim on lamivudine uptake was competitive, with an apparent Ki of 27.6 ,M. The uptake of lamivudine was also inhibited by nitrobenzylthioinosine, a representative inhibitor of nucleoside transport, and by other nucleoside analogues, such as azidothymidine and dideoxycytidine, that are excreted by renal tubular secretion. These findings suggest that efflux of lamivudine at the brush border membrane of renal tubular epithelium is mediated by an H+/lamivudine antiport system, which may correspond to the H+/organic cation antiport system, and that this system is also involved in the renal secretion of other nucleoside analogues. [source]


    Ionic liquids in the synthesis and modification of polymers

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2005
    Przemys, aw Kubisa
    Abstract Ionic liquids are organic salts that are liquid at ambient temperatures, preferably at room temperature. They are nonvolatile, thermally and chemically stable, highly polar liquids that dissolve many organic, inorganic, and metallo-organic compounds. Many combinations of organic cations with different counterions are already known, and the properties of ionic liquids may be adjusted by the proper selection of the cation and counterion. In the last decade, there has been increasing interest in using ionic liquids as solvents for chemical reactions. The interest is stimulated not only by their nonvolatility (green solvents) but also by their special properties, which often affect the course of a reaction. In recent years, ionic liquids have also attracted the attention of polymer chemists. Although the research on using ionic liquids in polymer systems is still in its infancy, several interesting possibilities have already emerged. Ionic liquids are used as solvents for polymerization processes, and in several systems they indeed show some advantages. In radical polymerization, the kp/kt ratio (where kp is the rate constant of propagation and kt is the rate constant of termination) is higher than in organic media, and thus better control of the process can be achieved. Ionic liquids, as electrolytes, have also attracted the attention of researchers in the fields of electrochemical polymerization and the synthesis of conducting polymers. Finally, the blending of ionic liquids with polymers may lead to the development of new materials (ionic liquids may act as plasticizers, electrolytes dispersed in polymer matrices, or even porogens). In this article, the new developments in these fields are briefly discussed. 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4675,4683, 2005 [source]


    Octahedral distortion caused by hydrogen bonding in tris(diethylammonium) hexachloridoantimonate(III)

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010
    Maciej Bujak
    The factors influencing the distortion of inorganic anions in the structures of chloridoantimonates(III) with organic cations, in spite of numerous structural studies on those compounds, have not been clearly described and separated. The title compound, [(C2H5)2NH2]3[SbCl6], consisting of isolated distorted [SbCl6]3, octahedra that have C3 symmetry and [(C2H5)2NH2]+ cations, unequivocally shows the role played by hydrogen bonding in the geometry variations of inorganic anions. The organic cations, which are linked to the inorganic substructure through N,H...Cl hydrogen bonds, are clearly responsible for the distortion of the octahedral coordination of SbIII in terms of differences (,) in both Sb,Cl bond lengths [, = 0.4667,(6),] and Cl,Sb,Cl angles [, = 9.651,(17)]. [source]


    catena -Poly[bis(trimethylphenylammonium) [hexa-,-chlorido-dichloridotricuprate(II)]]: an alternating zigzag chain of CuCl4 and Cu2Cl6 complexes

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2010
    Marcus R. Bond
    The title compound, {(C9H14N)2[Cu3Cl8]}n, consists of parallel chains of alternating quasiplanar Cu2Cl6 and planar CuCl4 complexes separated by trimethylphenylammonium cations. Both inorganic complexes possess inversion symmetry. Pairs of neighboring chloride ions of the CuCl4 complex each form a symmetric bridge and an asymmetric bridge to Cu2Cl6 complexes on either side. The Cu2Cl6 complex contains two symmetric chloride bridges between the copper cations with a terminal chloride bound to each five-coordinated CuII ion. The CuCl4 complex completes its coordination environment by forming two long semicoordinate contacts to the bridging chloride ions of neighboring Cu2Cl6 complexes. The use of the bridging rather than the terminal chloride ions to form semicoordinate contacts generates a new zigzag chain structure that differs from the straight chain structures found for other A2Cu3Cl8 compounds. The zigzag chain structure is adopted so as to conform to the shorter repeat distance dictated by stacking of the organic cations. [source]


    Hydrogen-bonded frameworks of bis(2-carboxypyridinium) hexafluorosilicate and bis(2-carboxyquinolinium) hexafluorosilicate dihydrate

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2007
    Vladimir O. Gelmboldt
    In bis(2-carboxypyridinium) hexafluorosilicate, 2C6H6NO2+SiF62,, (I), and bis(2-carboxyquinolinium) hexafluorosilicate dihydrate, 2C10H8NO2+SiF62,2H2O, (II), the Si atoms of the anions reside on crystallographic centres of inversion. Primary inter-ion interactions in (I) occur via strong N,H...F and O,H...F hydrogen bonds, generating corrugated layers incorporating [SiF6]2, anions as four-connected net nodes and organic cations as simple links in between. In (II), a set of strong N,H...F, O,H...O and O,H...F hydrogen bonds, involving water molecules, gives a three-dimensional heterocoordinated rutile-like framework that integrates [SiF6]2, anions as six-connected and water molecules as three-connected nodes. The carboxyl groups of the cation are hydrogen bonded to the water molecule [O...O = 2.5533,(13),], while the N,H group supports direct bonding to the anion [N...F = 2.7061,(12),]. [source]


    Tetraethylammonium dihydrogenarsenate bis(arsenic acid) and 1,4-diazoniabicyclo[2.2.2]octane bis(dihydrogenarsenate) arsenic acid: hydrogen-bonded networks containing dihydrogenarsenate anions and neutral arsenic acid molecules

    ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2007
    Clare Lee
    The title compounds, (C8H20N)[H2AsO4][H3AsO4]2, (I), and (C6H14N2)[H2AsO4]2[H3AsO4], (II), are unusual salts containing organic cations, dihydrogenarsenate anions and neutral arsenic acid molecules. In (I), the dihydrogenarsenate anion lies across a twofold rotation axis in the space group C2/c, while the cation is disordered across a centre of inversion. The [H2AsO4], and H3AsO4 species interact by way of O,H...O hydrogen bonds, leading to sheets and a three-dimensional network for (I) and (II), respectively. [source]