Simultaneous determination of erlotinib and its isomeric major metabolites in human plasma using isocratic liquid chromatography–tandem mass spectrometry and its clinical application

This study developed a method for the simultaneous determination of erlotinib and its isomeric major metabolites, OSI‐413 and OSI‐420, in human plasma using an isocratic liquid chromatography–tandem mass spectrometry. Plasma specimens deproteinized with acetonitrile were separated using a 3‐µm particle size octadecylsilyl column. The m/z values of the precursor and product ions for the analytes were as follows: erlotinib, 394.2/278.2; and OSI‐413 and OSI‐420, 380.2/278.2. The total run time was 21 min and no peaks interfering with the analytes and internal standard (d₆‐erlotinib) in human plasma were observed. The calibration curves of erlotinib, OSI‐413 and OSI‐420 were linear over the concentration ranges of 10–3000, 2–500 and 2–100 ng/mL, respectively. The pretreatment recovery ratios were >86.1%. The intra‐ and inter‐assay precisions and accuracies were <12.7 and 89.0–108.9% for all analytes. This validated method was applied to the determination of plasma samples in lung cancer patients receiving 150 mg of oral erlotinib. The plasma concentration ranges of erlotinib, OSI‐413 and OSI‐420 were 373–2354, 15.7–379 and 2.5–43.6 ng/mL, respectively. In conclusion, the present method can be helpful for evaluating the plasma exposures of erlotinib and its major isomeric metabolites in clinical settings. Copyright © 2014 John Wiley & Sons, Ltd.     

Scale factor effect of RGB monochromatic speckle grains on color speckle distribution

Optical Review - A measured color speckle distribution around a white point plotted in the xyYnorm color space was compared with the color speckle distribution calculated by the conventional...     

Construction of type II blow-up solutions for a semilinear parabolic system with higher dimension

This paper is concerned with blow-up solutions for a semilinear parabolic system with a power type nonlinearity. Non self-similar blow-up solution is constructed by the matched asymptotic expansions. One component of this solution converges to the singular steady state, and another component converges to zero in self-similar variables.     

Conductive liquid crystalline compounds having a piperazine structure

New conductive thermotropic liquid crystalline materials having a piperazine ring in the central core: 1-[4-(9-decenyloxy)phenyl]-4-alkylpiperazines (6) were synthesized. The mesomorphic behaviours of these compounds and their conductivity in the liquid crystal phase were measured. The principal features of these compounds are to exhibit a smectic B phase around room temperature (for example 6: Cr 50 SmB 81 I, °C) and to exhibit a large dark current (6d: 430 μA cm^?2, applied voltage 20 V, at 70°C) in the smectic B phase.     

Electron Spin Resonance Study on Grafting of Tetrafluoroethylene onto Polyethylene

An ESR study has been made on the course of grafting of tetrafluoroethylene onto polyethylene. Alkyl and allyl radicals trapped in the polymers were measured under various grafting conditions. It was observed that alkyl radicals decay very rapidly when monomers are in contact with the irradiated polymer, while allyl radicals decay very slowly even in the presence of monomers as in the decay of radicals in irradiated polymers without monomers. The effect of pre-irradiation temperature on grafting was also studied, and the rate of grafting was found to be much faster for lower pre-irradiation temperatures. From these experimental results it was concluded that alkyl radicals play an important Tole in the initiation reaction of grafting.     

Simple and validated UHPLC method coupled to UV detection for determination of daptomycin in human plasma and urine

Daptomycin, a lipopeptide antibiotic with excellent activity against Gram‐positive bacteria, is excreted primarily by the kidneys. Development of effective chromatographic methodologies for the determination of daptomycin in human specimens is necessary for clinical use. This study developed a simple and validated ultra‐high‐performance liquid chromatography method coupled to ultraviolet detection for determination of daptomycin in human plasma and urine. After the pretreatments involving protein precipitation, the supernatants were separated using a 2.3 µm particle size octadecylsilyl column, and the run time was 1 min. The calibration curves were linear over the concentration ranges of 2–200 mg/L for plasma and 25–300 mg/L for urine. Intra‐ and inter‐assay precision and accuracy values of plasma were within 13.5 and 92–100% and within 10.7 and 100–107%, respectively. Those of urine were within 5.0 and 101–104% and within 3.7 and 100–101%, respectively. The validated method was applied to the determination of plasma and urine samples in patients receiving 4–6 mg/kg of intravenous daptomycin, resulting in sufficient sensitivity for evaluating the plasma exposure and urinary excretion. In conclusion, the present method with acceptable analytical performance can be helpful for evaluating the pharmacokinetic disposition of daptomycin in clinical settings. Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of Protecting Groups and Solvents in Anomeric O-Alkylation of Mannopyranose1

Abstract

Anomeric O-alkylation of mannopyranoses with various protecting groups was investigated using mannose derivatives and 2,3-O-isopropylidene-l-O-trifluoro-methanesulfonyl-D-glycerol (1) as alkylating agent. Generally, in polar solvents higher α/β ratios were obtained than in nonpolar solvents. Sterically demanding protecting groups at the 6-O-position and polar solvents led to higher yields. Reactivity differences were explained by different complex formation. Based on these results mannopyranosyl-α(1-4) glucopyranosides 26 and 27 were synthesized using mannose derivatives 5 and 6 having a 6-O-(p-methoxyphenyl)diphenylmethyl group and galactosyl trifluoromethane-sulfonate 24 or nonafluorobutanesulfonate (nonaflate) 25, respectively, as alkylating agents.     

Intense Red-Blue Luminescence Based on Superfine Control of Metal–Metal Interactions for Self-Assembled Platinum(II) Complexes

A series of assembled Pt^II complexes comprising N-heterocyclic carbene and cyanide ligands was constructed using different substituent groups, [Pt(CN)₂(R-impy)] (R-impyH⁺=1-alkyl-3-(2-pyridyl)-1H-imidazolium, R=Me ( Pt-Me ), Et ( Pt-Et ), ⁱPr ( Pt- ⁱ Pr ), and ^tBu ( Pt- ^t Bu )). All the complexes exhibited highly efficient photoluminescence with an emission quantum yield of 0.51–0.81 in the solid state at room temperature, originating from the triplet metal-metal-to-ligand charge transfer (³MMLCT) state. Their emission colors cover the entire visible region from red for Pt-Me to blue for Pt- ^t Bu . Importantly, Pt- ^t Bu is the first example that exhibits blue ³MMLCT emission. The ³MMLCT emission was proved and characterized based on the temperature dependences of the crystal structures and emission properties. The wide-range color tuning of luminescence using the ³MMLCT emission presents a new strategy of superfine control of the emission color.     

On finite truncation of infinite shot noise series representation of tempered stable laws

Tempered stable processes are widely used in various fields of application as alternatives with finite second moment and long-range Gaussian behaviors to stable processes. Infinite shot noise series representation is the only exact simulation method for the tempered stable process and has recently attracted attention for simulation use with ever improved computational speed. In this paper, we derive series representations for the tempered stable laws of increasing practical interest through the thinning, rejection, and inverse Lévy measure methods. We make a rigorous comparison among those representations, including the existing one due to Imai and Kawai [29] and Rosiński (2007) [3], in terms of the tail mass of Lévy measures which can be simulated under a common finite truncation scheme. The tail mass are derived in closed form for some representations thanks to various structural properties of the tempered stable laws. We prove that the representation via the inverse Lévy measure method achieves a much faster convergence in truncation to the infinite sum than all the other representations. Numerical results are presented to support our theoretical analysis.