Complexation behavior of antiestrogen drug tamoxifen citrate with natural and modified β-cyclodextrins

Inclusion complexes of the poorly-soluble antiestrogen drug tamoxifen citrate (TMX) were prepared with β-cyclodextrin (β-CD) and 2,3-di-O-hexanoyl-β-cyclodextrin (β-CDC6) being natural and amphiphilic cyclodextrins, respectively using the co-lyophilization technique. Complexation occurred in aqueous medium for natural cyclodextrin β-CD and a medium of water:ethanol mixture for the amphiphilic cyclodextrin β-CDC6. The complexes were characterized using analytical techniques including Differential Scanning Calorimetry (DSC), Fourier Transform Infrared spectroscopy (FTIR) and proton Nuclear Magnetic Resonance Spectrometry (¹H NMR). Anticancer efficacies of the complexes were determined against MCF-7 human breast carcinoma cell line with MTT assay. It was found that tamoxifen citrate can be incorporated in the cavity for β-CD and both in the cavity and the aliphatic chains for β-CDC6. The latter having two hydrophobic sites for inclusion of water-insoluble drug exhibited significantly higher anticancer efficacy accordingly.     

Transition metal complexes with tridentate salicylaldimine derived from 3,5-di-t-butylsalicylaldehyde

Several new binuclear Cu^II, Ni^II, OV^IV and Mn^II complexes of tridentate salicylaldimine (H₂L), obtained from 3,5-di-t-butylsalicylaldehyde and o-aminophenol, have been prepared and characterized by analytical, spectroscopic (i.r., u.v.–vis., e.s.r.) techniques, magnetic and thermal measurements. The adduct formation or dissociation of these complexes in the presence of strongly coordinating solvents like pyridine and DMSO did not take place. The complexation of Co^II with H₂L is accompanied by intramolecular electron transfer from the metal to the coordinated ligand yielding the radical ligand Co^III complex (g = 2.003, A ^Co = 10 G). The e.s.r. spectra of the Cu^II, OV^IV and Mn^II complexes in the solid state and in solution are very broad due to intramolecular dipolar antiferromagnetic interactions.     

An Infrared Spectroscopic Study on the Hofmann-diam-type 1,9-Diaminononanemetal(II) Tetracyanonickelate(II)-Aromatic Guest Clathrates: M(H2N(CH2)9NH2)Ni(CN)4 ċG(M = Cd or Ni; G = Benzene, Naphthalene, Anthracene or Phenanthrene

IR spectra of M(1,9-Diaminononane)Ni(CN)₄G (M = Cd or Ni; G = benzene, naphthalene, anthracene or phenanthrene) are reported. The spectral data suggest that the host structures in these clathrates are similar to those of Hofmann-, -diaminoalkane type clathrates.     

Synthesis and electrochemical characterization of biphenyl-malonic ester substituted cobalt,copper, and palladium phthalocyanines

Phthalocyanines with four biphenyl-malonic ester groups on the periphery were synthesized by cyclotetramerization of 4-(1,1-dicarbethoxy-2-(4-biphenyl)-ethyl)-phthalonitrile. The new compounds were characterized by elemental analyses, FT-IR, ¹H NMR, ¹³C NMR, UV–Vis, and MASS spectral data. Electrochemical behaviors of novel Co(II), Cu(II), and Pd(II) phthalocyanines were investigated by cyclic voltammetry, potential differential pulse voltammetry, and applied potential chronocoulometry techniques. While Cu(II) and Pd(II) phthalocyanines give up to four common phthalocyanine ring reductions, Co(II) phthalocyanine gave two ligand-centered and two metal-centered redox processes. HOMO–LUMO gap of the complexes are comparable with the reported MPc papers.     

Stereospecific synthesis of a new class of aminocyclitol with the conduramine D-2 configuration

A new aminocyclitol derived from bicyclo[4.2.0^1,6]octane was synthesized starting from cyclooctatetraene. Photooxygenation of trans-7,8-diacetoxy-bicyclo[4.2.0]octa-2,4-diene afforded a bicyclic endoperoxide. Reduction of the endoperoxide with thiourea followed by a palladium-catalyzed ionization/cyclization reaction gave an oxazolidinone derivative. Oxidation of the double bond in the oxazolidinone with KMnO₄ followed by acetylation gave the oxazolidinone-tetraacetate whose exact configuration was determined by X-ray diffraction analysis. Hydrolysis of the oxazolidinone ring and removal of the acetate groups furnished the desired aminocyclitol.     

Diaquabis(4‐fluorobenzoato‐κO)bis(nicotinamide‐κN)cobalt(II)

The title compound, [Co(C₇H₄FO₂)₂(C₆H₆N₂O)₂(H₂O)₂], is a three‐dimensional hydrogen‐bonded supramolecular complex. The Co^II ion resides on a centre of symmetry and is in an octahedral coordination environment comprising two pyridyl N atoms, two carboxylate O atoms and two O atoms from water molecules. Intermolecular N—H...O and O—H...O hydrogen bonds produce R₃²(6), R₂²(12) and R₂²(16) rings, which lead to two‐dimensional chains. An extensive three‐dimensional network of C—H...F, N—H...O and O—H...O hydrogen bonds and π–π interactions are responsible for crystal stabilization.     

Thermal Behaviour Studies on Some Heterotrinuclearpolyacids

An improved method for the synthesis of four heterotrinuclearpolyacids of the type: H_x[EM′_yM″_zO₄₀⋅nH₂O (E=P, Si; M′=Mo, W; M″=V, W) was elaborated. The studied compounds were characterized by elemental analysis, IR spectra and thermal behaviour over 20–800°C temperature range. This revised version was published online in August 2006 with corrections to the Cover Date.     

Predictability and stopping on lattices of sets

Summary As a first step in the development of a general theory of set-indexed martingales, we define predictability on a general space with respect to a filtration indexed by a lattice of sets. We prove a characterization of the predictable -algebra in terms of adapted and left-continuous processes without any form of topology for the index set. We then define a stopping set and show that it is a natural generalization of the stopping time; in particular, the predictable -algebra can be characterized by various stochastic intervals generated by stopping sets.Research supported by a grant from the Natural Sciences and Engineering Research Council of CanadaResearch partially done while the second author was visiting the University of Ottawa. He wishes to thank the Department of Mathematics for its hospitality     

Studies on the Non-Isothermal Decomposition of H3PMo12O40·xH2O and H4PVMo11O40·yH2O

This paper reports a comparative study of the non-isothermal decompositions of the heteropolyacids HPM and HPVM, with structures consisting of Keggin units (KUs). Non-isothermal analysis at low heating rates demonstrated the existence of 4 crystal hydrate species, depending on the temperature. The stability domains of the anhydrous forms of HPM and HPVM were found to be 150–380°C, respectively. Processing of the TG curves obtained at different heating rates by the Ozawa method revealed that the decomposition of anhydrous HPM takes place according to a unitary mechanism, whilst for anhydrous HPVM two mechanisms are observed. Thus, the first part of the constitution water is lost simultaneously with the departure of vanadium from the KU as VO²⁺, while the second part is lost at higher temperatures as in the case HPM. This revised version was published online in August 2006 with corrections to the Cover Date.     

The effect of series resistance on capacitance-voltage characteristics of Schottky barrier diodes

The capacitance-voltage (C-V) and current-voltage (I-V) characteristics of the Ti/p-Si Schottky barrier diodes (SBDs) have been investigated taking into account the effect of the interface states and series resistance of the device. The forward C-V measurements have been carried out in the range frequency of 0.3-2 MHz (at six different frequencies). It is seen that the forward C-V plots exhibit anomalous peaks in the presence of a series resistance. It has been experimentally determined that the peak positions in the C-V plot shift towards lower voltages and the peak value of the capacitance decreases with increasing frequency. In addition to, the effect of series resistance on the capacitance is found appreciable at higher frequencies due to the capacitance decreases with increasing frequency.