Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.2.42 (DTA)
 1,693 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to formulate and evaluate microencapsulated controlled release preparations of zidovudine using ethyl cellulose as the retardant material with high entrapment efficiency and extended release. Microspheres were prepared by water-in-oil-in-oil (w/o/o) double emulsion solvent diffusion method. A mixed solvent system (MSS) consisting of acetonitrile and dichloromethane in a 1:1 ratio and light liquid paraffin were chosen as primary and secondary oil phases, respectively. Span 80 was used as the surfactant for stabilizing the secondary oil phase. The prepared microspheres were white, free flowing and spherical in shape and characterized by drug loading, infrared spectroscopy (IR), differential scanning colorimetry (DSC) and scanning electron microscopy (SEM). The in vitro release studies were performed using PH 7.4 phosphate buffer. The drug loaded microspheres showed 41-55% of entrapment and release was extended up to 18-20 h. The infrared spectra and DSC and DTA thermograms showed stable character of zidovudine in the drug loaded microspheres and revealed the absence of drug-polymer interactions. SEM studies showed that the microspheres are spherical and porous in nature. Data obtained from in vitro release were fitted to various kinetic models and high correlation was obtained in the Higuchi model. The drug release was found to be diffusion controlled.
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PMID:Formulation and in vitro evaluation of ethyl cellulose microspheres containing zidovudine. 1642 58

The preparation and structural characterization of a novel Ti-O-Ti bonding complex constructed in the mono-lacunary alpha-Keggin polyoxometalate (POM), are described. The water-soluble, crystalline complex with a formula of K5H2[[{Ti(OH)(ox)}2(micro-O)](alpha-PW11O39)] x 13H2O 1 was prepared in 30.2% (0.60 g scale) yield in a 1 : 3 molar-ratio reaction of the tri-lacunary species of alpha-Keggin POM, Na9[A-PW9O34] x 19H2O, with the titanium(IV) source, K2TiO(ox)2 x 2H2O (H2ox = oxalic acid), in HCl-acidic solution (pH 0.08), and characterized by complete elemental analysis, thermogravimetric and differential thermal analyses (TG/DTA), FTIR, solution (31P, 183W, 1H and 13C) NMR spectroscopy and X-ray crystallography. The complex was also obtained in 47.6% (0.81 g scale) yield in a 1 : 2 molar-ratio reaction of the mono-lacunary Keggin POM, K7[PW11O39] x 10H2O, with the anionic titanium(IV) complex under acidic conditions. The molecular structure of [[{Ti(OH)(ox)}2(micro-O)](alpha-PW11O39)]7- 1a, was successfully determined. This POM in the solid state is composed of one host (mono-lacunary site) and two guests (two octahedral Ti groups), in contrast to most titanium (IV)-substituted POMs consisting of one host and one guest. On the other hand, the 31P NMR measurements revealed that in aqueous solution this POM was present under a dissociation equilibrium which depends upon both temperature and pH.
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PMID:Novel Ti-O-Ti bonding species constructed in a metal-oxide cluster. 1647 Oct 56

A new two-dimensional framework germanate, Ge3O5(OH)4[C2N2H10] (denoted ICMM-8), with a 3:9 Ge:O ratio has been synthesized, using a mixture of pyridine, water, and ethanol as the solvent and 1,4-diazabicyclo[2.2.2]octane and ethylenediamine as the structure-directing agents, under solvothermal conditions. The structure was determined by single-crystal X-ray diffraction. In this new compound, the GeO2 natrolite-type infinite four and eight R-containing layers appears for the first time in a pure GeO2 framework. The total 2D structure is built up from SBU-6, four tetrahedra, and two octahedra. The hydroxyl groups occupy four positions of each octahedral germanium atom. The compound is characterized by IR spectra and TGA-DTA. Crystal data: Ge3O5(OH)4[C2N2H10], monoclinic space group P2(1)/c; a = 11.3570(9) Angstroms, b = 8.8819(7) Angstroms, c = 9.9200(8) Angstroms, beta = 90.710(1), V = 1000.6(1) Angstroms(3), Z = 4, R(1) = 0.044 (I > 2(I)), and wR(2) = 0.1051 (all data).
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PMID:GeO2 natrolite-type infinite four and eight R-containing layers in a 2D pure-Ge framework: Ge3O5(OH)4[C2N2H10]. 1647 70

A novel ligand, diethylenetriamine-N,N''-bis(acetyl-p-hydroxybenzoyl hydrazine)-N,N',N''-triacetic acid (H3L) was synthesized and characterized on the basis of elemental analysis, molar conductivity, 1H-NMR spectrum, FAB-MS, TG-DTA analysis and IR spectrum. Its complex of Gd(III) holding promise of magnetic resonance imaging (MRI) was synthesized, and relaxivity (R1) of complex and Gd(DTPA)2- used as a control was determined in water solution, respectively. The relaxivity of GdL (R1 = 6.39 l.mmol(-1).s(-1)) was larger than that of Gd(DTPA)2- (R1 = 4.34 l.mmol(-1).s(-1)). The relaxivity of GdL has also been investigated in human serum albumin (HSA) solution, the relaxivity of GdL was enhanced from 6.39 l.mmol(-1).s(-1) in water solution to 7.69 l.mmol(-1).s(-1) in HSA solution. In addition, thermodynamics stability constant of GdL was determined. The results showed that complex of GdL is a prospective MRI contrast agent, although the thermodynamic stability constant of GdL complex (K(GdL) = 10(19.56)) was a little less than that of Gd(DTPA)2- (K(Gd-DTPA) = 10(20.73)).
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PMID:Synthesis, thermodynamics stability constant and relaxation properties of neutral Gd(III) complex with derivative from diethylene triamine pentaacetic acid and p-hydroxybenzoyl hydrazine. 1650 4

Five novel antimony(III) complexes with the mono- and bis(thiosemicarbazone) ligands of 2N1S or 4N2S donor atoms, N'-[1-(2-pyridyl)ethylidene]morpholine-4-carbothiohydrazide (Hmtsc, L1) and bis[N'-[1-(2-pyridyl)ethylidene]]-1,4-piperazinedicarbothiohydrazide (H(2)ptsc, L7), and the tridentate semicarbazone ligand of 2N1O donor atoms, 2-acetylpyridine semicarbazone (Hasc, L2b), were prepared by reactions of SbCl(3) or SbBr(3), and characterized by elemental analysis, TG/DTA, FT-IR and (1)H NMR spectroscopy. The crystal and molecular structures of five antimony(III) complexes were determined by single-crystal X-ray structure analysis. The neutral, 6-coordinate antimony(III) complexes ([Sb(mtsc)Cl(2)] 1, [Sb(mtsc)Br(2)] 2, [Sb(asc)Cl(2)] 3 and [Sb(asc)Br(2)] 4) are depicted with one electron pair (5s(2)) of the antimony(III) atom, deprotonated forms of multidentate thiosemicarbazone or semicarbazone ligands, and two monodentate halogen ligands, respectively. In the dimer complex 5 ([Sb(2)(ptsc)Cl(4)]) with the ligand in which two tridentate thiosemicarbazone moieties are connected by the piperazine moiety, each antimony(III) was also described as a neutral 6-coordinate structure. These antimony(III) complexes were thermally stable around 200 degrees C. Water-soluble antimony(III) complexes 1 and 2 showed moderate antimicrobial activities against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and -negative bacteria (Escherichia coli and Pseudomonas aeruginosa), yeasts (Candida albicans and Saccharomyces cerevisiae) and molds (Aspergillus niger and Penicillium citrinum). Complex 5 showed moderate antimicrobial activities against four bacteria, and two molds, while the ligand itself showed only modest antimicrobial activities against selected bacteria (B. subtilis, E. coli and S. aureus). The molecular structures and antimicrobial activities of antimony(III) complexes were compared with those of bismuth(III) complexes in the same 15 group in the periodic table.
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PMID:Syntheses, crystal structures and antimicrobial activities of 6-coordinate antimony(III) complexes with tridentate 2-acetylpyridine thiosemicarbazone, bis(thiosemicarbazone) and semicarbazone ligands. 1654 59

The ternary chelates of piroxicam (Pir) and tenoxicam (Ten) with Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) in the presence of various amino acids such as glycine (Gly) or dl-phenylalanine (PhA) were prepared and characterized with different physicochemical methods. IR spectra confirm that Pir and Ten behave as a neutral bidentate ligand coordinated to the metal ions via the pyridine-N and carbonyl group of the amide moiety. Gly molecule acted as a uninegatively monodentate ligand and coordinate to the metal ions through its deprotonated carboxylic group. In addition, PhA acted as a uninegatively bidentate ligand and coordinate to the metal ions through its deprotonated carboxylic and amino groups. The solid reflectance spectra and magnetic moment measurements confirm that all the chelates have octahedral geometrical structures while Cu(II)- and Zn(II)-ternary chelates with PhA have square planar geometrical structures. Thermal behaviour of the complexes is extensively studied using TG and DTA techniques. TG results show that water molecules (hydrated and coordinated) and anions are removed in the first and second steps while Gly, PhA, Pir and Ten are decomposed in the next and subsequent steps. The pyrolyses of the chelates into different gases are observed in the DTA curves as exo- or endothermic peaks. Also, phase transition states are observed in some chelates. Different thermodynamic parameters are calculated using Coats-Redfern method and the results are interpreted.
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PMID:Synthesis and thermal characterization of new ternary chelates of piroxicam and tenoxicam with glycine and DL-phenylalanine and some transition metals. 1661 14

The ternary rare-earth complexes were synthesized using cinnamic acid (L), 2,2'-bipyridine (bipy) and rare-earth (RE= Tb, Eu, Gd, Nd) in ethanol solution. Their compositions were confirmed to be REL3 x bipy by the element analysis, infrared and ultraviolet absorption spectra, and DTA-TGA, respectively. The spectral properties of complexes and the fluorescent property of EuL3 x bipy were discussed. The fluorescence intensity of EuL3 is 4.5 times stronger than that of EuL3 x bipy x H2O.
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PMID:[Synthesis, characterization and fluorescent property of ternary complexes of rare-earth, cinnamic acid and 2,2'-bipyridine]. 1683 34

A new ligand, N,N'-di(pyridine N-oxide-2-yl)pyridine-2,6-dicarboxamide (LH2) and its several lanthanide (III) complexes (La, Eu, Gd, Tb, Y) were synthesized and characterized in detail based on elemental analysis, conductivity measurements, IR, 1H NMR, MS (FAB) and UV spectra and TG-DTA studies. The results indicated that the composition of these binary complexes is [Ln(LH2)(NO3)2.H2O]NO3.nH2O (n=0-1); while the ligand has a good planar structure with strong hydrogen bonds. The fluorescence spectra exhibits that the Tb (III) complex and the Eu (III) complex display characteristic metal-centered fluorescence in solid state while ligand fluorescence is completely quenched. However, the Tb (III) complex displays more effective luminescence than the Eu (III) complex, which is attributed to especial effectivity in transferring energy from the lowest triplet energy level of the ligands (T) onto the excited state (5D4) of Tb (III) than that (5D1) of Eu (III).
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PMID:Synthesis, characterization and luminescence property of N,N'-di(pyridine N-oxide-2-yl)pyridine-2,6-dicarboxamide and corresponding lanthanide (III) complexes. 1683 6

A novel ligand, diethylenetriamine-N,N''-bis(acetyl-isoniazid)-N,N',N''-triacetic acid (H(3)L) has been synthesized from diethylene triamine pentaacetic acid (DTPA) and isoniazid. Ligand and its five neutral rare earth (RE=La, Sm, Eu, Gd, Tb) complexes holding promise of magnetic resonance imaging (MRI) were characterized on the basis of elemental analysis, molar conductivity, (1)H-NMR spectrum, FAB-MS, TG-DTA analysis and IR spectrum. The relaxivity (R(1)) of complexes and Gd(DTPA)(2-) used as a control were determined. The relaxivity of LaL, SmL, EuL, GdL, TbL and Gd(DTPA)(2-) were 0.14, 1.66, 3.14, 6.08, 2.79 and 4.34 l.mmol(-1).s(-1), respectively. The spin-lattice relaxivity of GdL was larger than that of Gd(DTPA)(2-). The relaxivity of GdL had also been investigated in human serum albumin (HSA) solution, the relaxivity of GdL was enhanced from 6.08 l.mmol(-1).s(-1) in water solution to 9.09 l.mmol(-1).s(-1) in HSA solution. In addition, thermodynamics stability constant of GdL complex was determined, the thermodynamic stability constant of GdL complex (K(GdL)=10(20.84)) was a few larger than that of Gd(DTPA)(2-) (K(Gd-DTPA)=10(20.73)). The results showed that complex of GdL may be a prospective MRI contrast agent with low osmotic pressure due to non-ion complex, high spin-lattice relaxivity, good stability and binding affinity for the serum protein.
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PMID:Synthesis neutral rare earth complexes of diethylenetriamine-N,N''-bis(acetyl-isoniazid)-N,N',N''-triacetic acid as potential contrast enhancement agents for magnetic resonance imaging. 1688 Jun 71

Biochemical sludges of sewage and petrochemistry and surplus sludge were taken as raw materials to prepare adsorbents for flue gas desulfurization by pyrolysis. To compare with active carbon, the abilities of adsorbents made from different sludges were studied by SEM, X-ray diffraction diagram, TG and DTA, pore characteristics and elements analysis, and the adsorption mechanisms of systems of SO2 -O2-N2 and SO2-O2-H2O(g)-N2 were studied by FTIR. Results indicated that the desulfurization performance of adsorbent made from surplus sludge was better, subsequent was petrochemical sludge, and the adsorbent made from biochemical sludge of sewage was worse. The desulfurization efficiency of adsorbent made from surplus sludge was slightly lower than active carbon. In the system of SO2-O2-N2, physical adsorption was primary, but in the condition of water, chemical adsorption was primary, where catalysis and oxidation of SO2 took place in sludge-derived adsorbent. In adsorption process, the adsorption depends on micropore structure.
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PMID:[Preparation of adsorbent made from sewage sludge and its spectrum properties]. 1688 62


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