Liquid Chromatography-Electrospray Mass Spectrometry Determination of Ibogaine and 12-Hydroxy-Ibogamine in Human Urine

A specific and sensitive liquid chromatography-electrospray ionization mass spectrometry method was developed for the determination of ibogaine and noribogaine in human urine. The work-up procedure involved a solid phase extraction of the compounds and the internal standard (fluorescein) using Oasis HLB columns. The system used a Zorbax eclipse XDB C8 analytical column packed with 5µm diameter particles as the stationary phase. The mobile phase consisted of a 20-min gradient (mobile phase A: 0.02% (v/v) trimethylamine in acetonitrile, mobile phase B: 2 mM ammonium formate buffer (pH 3)). Mass spectrometric data were acquired in single ion monitoring mode at m/z 311.1, 297.2 and 333 for ibogaine, noribogaine and fluorescein, respectively. The drug/internal standard peak area ratios were linked via a quadratic relationship to concentrations (1.78?358 μg L^?1 for ibogaine; 2?400 μg L^?1 for noribogaine). Precision ranged from 5.8 to 14.8% and accuracy was between 93.2 and 112.9%. Mean extraction recoveries of ibogaine, noribogaine and fluorescein were 70.0, 81.7 and 94.8%, respectively. The extraction efficiency was independent of concentration over the range studied. The lower limits of quantitation were 1.78 μg L^?1 for ibogaine and 2 μg L^?1 for noribogaine. In this paper, extensive stability testing was undertaken using a wide range of storage conditions. This method was found suitable for urine analysis of a poisoning involving ingestion of drink made from powdered root of shrub Tabernanthe iboga.     

Crystalline molecular alloys

The dicationic tecton 1-2H(+) leads in the presence of anionic M(CN)(6)(3-) complexes to two almost identical crystalline systems A (M = Fe) and B (M = Co) composed of 2-D H-bonded networks and water molecules. The epitaxial growth of B on A used as seed or A on B generates crystalline molecular alloys.     

Study and characterization of virgin and recycled LDPE/PP blends

Recycling of mixed plastic wastes composed of low-density polyethylene (LDPE) matrix and polypropylene (PP) was carried out by compounding using single-screw or twin-screw extruders. Blends of virgin polymers have been prepared to compare mechanical properties of both virgin and regenerated materials. First, a model composition of virgin LDPE/PP blend was prepared to study the effect of process parameters and that of different types of compatibilizers. Second, the results were applied to plastic wastes coming from industrial post-consumer plastic wastes. By adding compatibilizing agents such as ethylene-propylene-diene monomer, ethylene-propylene monomer, or PE-g-(2-methyl-1,3-butadiene) graft copolymer, elongation at break and impact strength were improved for all blends. The effect of these various copolymers is quite different and is in relation with their chemical structure. The recycled blends exhibit suitable properties leading to applications that require good mechanical properties.     

Pharmacomodulation of a ligand targeting the HBV capsid hydrophobic pocket

Hepatitis B virus (HBV) is a small enveloped retrotranscribing DNA virus and an important human pathogen. Its capsid-forming core protein (Cp) features a hydrophobic pocket proposed to be central notably in capsid envelopment. Indeed, mutations in and around this pocket can profoundly modulate, and even abolish, secretion of enveloped virions. We have recently shown that Triton X-100, a detergent used during Cp purification, binds to the hydrophobic pocket with micromolar affinity. We here performed pharmacomodulation of pocket binders through systematic modifications of the three distinct chemical moieties composing the Triton X-100 molecule. Using NMR and ITC, we found that the flat aromatic moiety is essential for binding, while the number of atoms of the aliphatic chain modulates binding affinity. The hydrophilic tail, in contrast, is highly tolerant to changes in both length and type. Our data provide essential information for designing a new class of HBV antivirals targeting capsid–envelope interactions.

Small-molecule binding to the Hepatitis B virus core protein hydrophobic pocket, a possible strategy for targeting viral particle assembly.     

Green ultrasound-assisted extraction of carotenoids based on the bio-refinery concept using sunflower oil as an alternative solvent

A green, inexpensive and easy-to-use method for carotenoids extraction from fresh carrots assisted by ultrasound was designed in this work. Sunflower oil was applied as a substitute to organic solvents in this green ultrasound-assisted extraction (UAE): a process which is in line with green extraction and bio-refinery concepts. The processing procedure of this original UAE was first compared with conventional solvent extraction (CSE) using hexane as solvent. Moreover, the UAE optimal conditions for the subsequent comparison were optimized using response surface methodology (RSM) and ultra performance liquid chromatography – diode array detector – mass spectroscopy (UPLC–DAD–MS). The results showed that the UAE using sunflower as solvent has obtained its highest β-carotene yield (334.75 mg/l) in 20 min only, while CSE using hexane as solvent obtained a similar yield (321.35 mg/l) in 60 min. The green UAE performed under optimal extraction conditions (carrot to oil ratio of 2:10, ultrasonic intensity of 22.5 W cm^?2, temperature of 40 °C and sonication time of 20 min) gave the best yield of β-carotene.     

Measurement of the generalized polarizabilities of the proton in virtual Compton scattering at Q2=0.92 and 1.76 GeV2

We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions P(LL)-P(TT)/epsilon and P(LT), and the electric and magnetic generalized polarizabilities (GPs) alpha(E)(Q2) and beta(M)(Q2) at momentum transfer Q(2)=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from piN intermediate states.     

Origin of the slow linear viscoelastic response of aqueous foams

We have studied the slow linear viscoelastic response of wet aqueous foams by macroscopic creep compliance measurements, combined to a diffusing-wave spectroscopy investigation of the local dynamics. The data strongly suggest that this rheological response arises from two distinct relaxation mechanisms: The first is due to the coarsening induced bubble rearrangements and governs the steady-state creep; the second results from the interplay between surface tension and surface viscosity of the gas-liquid interfaces and gives rise to a transient relaxation.     

Vibrational spectroscopic investigation of the phase diagram of a biomimetic lipid monolayer

The phase behavior of a biomimetic monolayer consisting of diphospholipid molecules on water is investigated using vibrational sum-frequency generation and fluorescence microscopy. In addition to the transition from the-molecularly disordered-liquid phase to the highly ordered and oriented con-densed phase, a novel, extremely sharp transition is observed at low compression, which is attributed to the uncurling of the hydrophobic alkane chains upon compression.