Simultaneous determination of oxycodone and its major metabolite, noroxycodone, in human plasma by high-performance liquid chromatography

Oxycodone (14-hydroxy-7,8-dihydrocodeinone) is a potent opioid receptor agonist. In the present study, a liquid-liquid extraction-based reversed-phase HPLC method with UV detection was validated and applied for the analysis of oxycodone and its major metabolite, noroxycodone, in human plasma. The analytes were separated using a mobile phase, consisting of acetonitrile and phosphate buffer (8:92, v/v) at a flow rate of 1 mL/min, and UV detection at 205 nm. The retention times for oxycodone, noroxycodone and codein (internal standard) were 14.7, 13.8 and 10.2 min, respectively. The validated quantitation range of the method was 2-100 ng/mL for oxycodone and 10-100 ng/mL for noroxycodone. The developed procedure was applied to assess the pharmacokinetics of oxycodone and its metabolite following administration of a single 20 mg oral dose of oxycodone hydrochloride to one healthy male volunteer.     

Uranium speciation in biofilms studied by laser fluorescence techniques

Biofilms may immobilize toxic heavy metals in the environment and thereby influence their migration behaviour. The mechanisms of these processes are currently not understood, because the complexity of such biofilms creates many discrete geochemical microenvironments which may differ from the surrounding bulk solution in their bacterial diversity, their prevailing geochemical properties, e.g. pH and dissolved oxygen concentration, the presence of organic molecules, e.g. metabolites, and many more, all of which may affect metal speciation. To obtain such information, which is necessary for performance assessment studies or the development of new cost-effective strategies for cleaning waste waters, it is very important to develop new non-invasive methods applicable to study the interactions of metals within biofilm systems. Laser fluorescence techniques have some superior features, above all very high sensitivity for fluorescent heavy metals. An approach combining confocal laser scanning microscopy and laser-induced fluorescence spectroscopy for study of the interactions of biofilms with uranium is presented. It was found that coupling these techniques furnishes a promising tool for in-situ non-invasive study of fluorescent heavy metals within biofilm systems. Information on uranium speciation and uranium redox states can be obtained.     

Solution and solid-state structure of the anion [Ag(2)[closo-CB(11)H(12)](4)](2-)

Addition of the carbene 1,3-dimesitylimidazol-2-ylidene (IMes) to a toluene solution of Ag[closo-CB(11)H(12)] results in the formation of the complex [(IMes)(2)Ag](2)[Ag(2)[closo-CB(11)H(12)](4)], the anionic component of which contains two silver(I) centers bridged by two carboranes in addition to one terminally bound carborane on each metal, in the solid-state. Comparison of the observed (11)B[(1)H] NMR chemical shifts of [(IMes)(2)Ag](2)[Ag(2)[closo-CB(11)H(12)](4)] or Ag[closo-CB(11)H(12)] with [NBu(4)][closo-CB(11)H(12)] in CD(2)Cl(2) demonstrates that the silver ion interacts significantly with the cage in solution. Theoretical investigations using the ab initio/GIAO/NMR method of [closo-CB(11)H(12)](-) and Na[closo-CB(11)H(12)] as model geometries for the silver salts support experimental evidence for these Ag...[BH] interactions in solution.     

Molecular transfer of surfactant bilayers: widening the range of substrates

Handling nanometer-thick films and nano-objects remains a challenge. Applying self-assembly properties of surfactants to nanomaterials manipulation may be the key to the fast, easy, cost-effective growth of 2D and 3D nanostructures. Newton black films (NBFs) are self-assembled bilayers of surfactant, well-organized, but fragile objects. To render such films amenable to practical applications, it is necessary to find ways to transfer them onto solid substrates. A method developed recently to transfer NBFs onto a solid substrate while preserving their molecular organization (Benattar, J.-J.; Nedyalkov, M.; Lee, F. K.; Tsui, O. K. C. Angew. Chem., Int. Ed. 2006, 45, 4186) is broadened here to different surfaces. The method requires hydrophobic, planar, atomically smooth surfaces. This study presents the adhesion of a fluorinated NBF surfactant onto hydrophobically treated silica and silicon surfaces (with etching or silanization). The structures of the free-standing film, bare substrates, and transferred films are investigated using X-ray reflectivity. The homogeneity of the surfaces before and after bilayer deposition is examined by atomic force microscopy (AFM). Multiple transfers are tested and described for the future development of more complex architectures involving many surfactant layers and inserted nanosized objects.     

Functionalized Porphyrin Discotic Liquid Crystals: Photoinduced Charge Separation and Trapping

Individual members of a family of highly absorptive porphyrins bearing symmetrically positioned flexible side chains form discotic liquid crystalline mesophases at modest temperature ranges. The order of this phase is preserved when a thin layer of this self-assembled material is cooled to room temperature. Exposure of such films to visible excitation, with or without an externally applied electrical field, produces photovoltaic effects and/or charge trapping. The latter effect constitutes the basis for optoelectronic information storage.     

Maize kernel hardness classification by near infrared (NIR) hyperspectral imaging and multivariate data analysis

The use of near infrared (NIR) hyperspectral imaging and hyperspectral image analysis for distinguishing between hard, intermediate and soft maize kernels from inbred lines was evaluated. NIR hyperspectral images of two sets (12 and 24 kernels) of whole maize kernels were acquired using a Spectral Dimensions MatrixNIR camera with a spectral range of 960-1662 nm and a sisuChema SWIR (short wave infrared) hyperspectral pushbroom imaging system with a spectral range of 1000-2498 nm. Exploratory principal component analysis (PCA) was used on absorbance images to remove background, bad pixels and shading. On the cleaned images, PCA could be used effectively to find histological classes including glassy (hard) and floury (soft) endosperm. PCA illustrated a distinct difference between glassy and floury endosperm along principal component (PC) three on the MatrixNIR and PC two on the sisuChema with two distinguishable clusters. Subsequently partial least squares discriminant analysis (PLS-DA) was applied to build a classification model. The PLS-DA model from the MatrixNIR image (12 kernels) resulted in root mean square error of prediction (RMSEP) value of 0.18. This was repeated on the MatrixNIR image of the 24 kernels which resulted in RMSEP of 0.18. The sisuChema image yielded RMSEP value of 0.29. The reproducible results obtained with the different data sets indicate that the method proposed in this paper has a real potential for future classification uses.     

Oxoneptunium(v) as part of the framework of a polyoxometalate

(NH4)14Na4[(Np3W4O15)(H2O)3(BiW9O33)3].62H2O (1) and (NH4)14.5Na3.5[(Np3W4O15)(H2O)3(SbW9O33)3].40.5H2O (2) each contain three neptunyl(v) moieties encapsulated within heteropolyoxotungstate frameworks in which axial {NpO2}+ oxygens form one face of a WO6 octahedron.     

Metallorganische Verbindungen mit N-substituierten 3-Hydroxy-2-methyl-4-pyridon-Liganden: quadratisch-planare Rhodium(I)-, Iridium(I)- und Palladium(II)-Komplexe

Organometallic Compounds with N -substituted 3-Hydroxy-2-methyl-4-pyridone Ligands: square planar Rhodium(I), Iridium(I), and Palladium(II) Complexes Reactions of [(OC)₂MCl]₂ (M = Rh, Ir) or [(cod)RhCl]₂ with the anions of N-Aryl or N-Alkyl substituted 3-hydroxy-2-methyl-4-pyridones (O–O′) yield complexes of the general formula [L₂M(O–O′)]. Compounds of this type are also available from reactions of [(OC)₂Rh(acac)] with the corresponding neutral ligands. Substitution of one carbonyl-ligand of the N-phenyl complex [(OC)₂Rh(C₁₂H₁₀NO₂)] ( 2 ) with cyclooctene affords [(OC)(C₈H₁₄)Rh(C₁₂H₁₀NO₂)] ( 8 ). The palladium complexes [(R₃P)Pd(O–O′)Cl] (R = Et, Bu), [(C₆H₄CH₂NMe₂) · Pd(O–O′)] and [(Et₃P)₂Pd(O–O′)]BF₄ ( 9 – 12 ) were synthesized from [(R₃P)PdCl₂]₂, [(C₆H₄CH₂NMe₂)PdCl]₂ or [(Et₃P)PdCl₂]. The structures of the N-methyl compounds [(OC)₂Rh(C₇H₈NO₂)] ( 1 ) and [(Ph₃P)Pd(C₇H₈NO₂)Cl] ( 9 ) were determined by single crystal X-ray diffraction.     

Asymmetric halogeno-bridged complexes: new reagents in organometallic synthesis and catalysis

Several methods to synthesize bimetallic complexes in which two different metal fragments are connected by halide bridges are described. Using simple starting materials a large pool of structurally defined bimetallic complexes with unique chemical reactivities can be prepared in short time. Applications in organometallic synthesis and homogeneous catalysis are discussed.