Simultaneous determination of prochlorperazine and its metabolites in human plasma using isocratic liquid chromatography tandem mass spectrometry

Oral prochlorperazine (PCZ), an antiemetic, undergoes extensive first-pass metabolism. The study developed a simultaneous analytical method for PCZ and its major metabolites, prochlorperazine sulfoxide (PCZSO), N-demethylprochlorperazine (NDPCZ) and 7-hydroxyprochlorperazine (PCZOH), in human plasma using an isocratic liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Deproteinized plasma specimens were separated using a 3 μm particle size octadecylsilyl column, and the run time was 10 min. The calibration curves were linear over the concentration ranges of 0.01-40 μg/L for PCZ, NDPCZ and PCZOH, and 0.05-80 μg/L for PCZSO. The intra- and inter-assay precisions and accuracies were within 7.0 and 99-104% and within 9.0 and 99-105%, respectively. The lower limits of quantification in human plasma were 10 ng/L for PCZ, NDPCZ and PCZOH, and 50 ng/L for PCZSO. The validated method was applied to the determination of plasma samples in 37 cancer patients receiving PCZ. Large interindividual variations were observed in plasma concentrations of PCZ, PCZSO, NDPCZ and PCZOH (relative standard deviation, 89.4, 88.7, 86.4 and 78.2%, respectively). In conclusion, this simultaneous LC-MS/MS method with acceptable analytical performance can be helpful for evaluating the pharmacokinetics of PCZ, including the determination of its metabolites in cancer patients and in clinical research.     

Shifting from Hydrogen Bond Network to π–π Stacking: A Key Mechanism for Reversible Thermochromic Sulfonated Poly(Ether Ether Ketone)

Sulfonated poly(ether ether ketone) (SPEEK) thin film performs reversible thermochromic property by developing the color to be yellowish at the temperature above 190 °C. The detailed analyses based on temperature‐dependent techniques suggest the thermal treatment inducing the shifting of the hydrogen bond network between the sulfonated group and the hydrated water molecules to the π–π stacking among aromatic rings in SPEEK chains. Although it is general that the polymer chain packing is unfavorable at high temperature, the present work shows a good example that when the polymer chains can form specific molecular interaction, such as π–π stacking, even in harsh thermal treatment, a rearrangement will effectively occur, which leads to an external stimuli‐responsive property.

     

Optical detection of organic hydrides with platinum-loaded tungsten trioxide

Tungsten trioxide powder with loading 0.1 wt% platinum (Pt/WO₃) was prepared for optical detection of organic hydrides such as cyclohexane, decalin by impregnation with PtCl₆^2? and subsequent calcination in air at 500 °C. The scanning electron microscopic observation of Pt/WO₃ shows that the Pt particles with mean diameters of 80–100 nm were on the surface of the WO₃ powder. The Pt/WO₃ showed coloration for 13% cyclohexane at higher 100 °C and for 1.3% cyclohexane at 200 °C. The in-situ XRD results of the Pt/WO₃ in coloring/bleaching change indicate that the coloring of Pt/WO₃ was caused by transformation of WO₃ to tungsten bronze. The analysis of reacted gas demonstrates that Pt on WO₃ produces only hydrogen and benzene through dehydrogenation of cyclohexane over 100 °C. It was founded that the Pt/WO₃ has potential of optical detection of organic hydrides by heating at higher 100 °C.     

Synthesis and characterization of (Bi,Cu)Sr2(RE,Ca)Cu2Oz (RE: Y or rare-earth element)

Samples with nominal compositions of x = 0–0.1 in (Bi_(1+3x)/3Cu_(2?3x)/3)Sr₂(RE_1?xCa_x)Cu₂O_z ((Bi,Cu)-“1-2-1-2”; RE: Y or rare-earth element) were synthesized by a solid-state reaction method and characterized by means of X-ray diffractometry (XRD). It is confirmed that the (Bi,Cu)-“1-2-1-2” forms only when RE = Y, Dy and Ho. Single- or nearly single-phase samples are obtained for x = 0–0.05 and the Ca-free composition of this compound is determined to be (Bi_1/3Cu_2/3)Sr₂RECu₂O_z. Since ionic radii of Y, Dy and Ho are very close to each other and this seems to be an essential factor for the stability of the (Bi,Cu)-“1-2-1-2”.     

Microscopic Fourier Transform Infrared Characterization on Two Types of Spherulite with Polymorphic Crystals in Poly(heptamethylene terephthalate)

FTIR microspectrometry with in situ temperature variation and IR‐peak‐mapping capability, and POM characterization were used to study the crystal distribution in dual spherulites in poly(heptamethylene terephthalate). By tracing the crystalline IR bands of the α‐crystal and β‐crystal to get the crystal distribution, the techniques resolve that the ringed and ringless spherulites comprise α‐ and β‐crystals, respectively. In addition, temperature‐dependent IR analyses on the spots related to the two crystals also reveal the α‐ and β‐crystals melt at 98 and 104 °C, respectively. The ringed and ringless spherulites were proven to be correlated with the α‐ and β‐crystal forms, respectively.

     

Double core hole creation and subsequent Auger decay in NH3 and CH4 molecules

Energies of the hollow molecules CH(4)(2+) and NH(3)(2+) with double vacancies in the 1s shells have been measured using an efficient coincidence technique combined with synchrotron radiation. The energies of these states have been determined accurately by high level electronic structure calculations and can be well understood on the basis of a simple theoretical model. Their major decay pathway, successive Auger emissions, leads first to a new form of triply charged ion with a core hole and two valence vacancies; experimental evidence for such a state is presented with its theoretical interpretation. Preedge 2-hole-1-particle (2h-1p) states at energies below the double core-hole states are located in the same experiments and their decay pathways are also identified.     

Time‐resolved wide‐angle X‐ray scattering measurements during the isothermal crystallization and ferroelectric phase‐transition processes of a vinylidene fluoride/trifluoroethylene copolymer

The time‐resolved measurement of wide‐angle X‐ray scattering was performed with a synchrotron radiation source during the processes of the isothermal crystallization and ferroelectric phase transition of a vinylidene fluoride/trifluoroethylene copolymer with 73 mol % vinylidene fluoride. When the sample was cooled rapidly from the melt to the temperature region of the paraelectric high‐temperature phase, the peak position of the 200/110 reflection shifted toward the higher angle side and the half‐width became narrower. This indicated an increase in the crystallite size with a more compact chain‐packing mode. Even when the temperature jump was made from the melt into the region of the ferroelectric or low‐temperature phase, the crystallization of the high‐temperature phase was first observed before the appearance of the low‐temperature phase. This was consistent with a prediction based on the so‐called Ostwald state rule: the thermodynamically unstable but kinetically preferable high‐temperature phase can appear first even when the thermodynamically more stable low‐temperature phase should be created. The time‐dependent intensity changes were analyzed with the Avrami kinetic equation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4175–4181, 2004     

Amyloid‐like Nanofibrillation of Metal‐Organic Complex Arrays Ruled by Their Precisely Designed Metal Sequences

Self‐assembly of a series of dimetallic sequences constructed on a backbone with two successive tyrosine moieties ( Fmoc‐M ¹ ‐M ² ‐CO₂H ) revealed that the resultant morphology is clearly dependent on the metal sequence, where Re‐containing sequences such as homometallic Fmoc‐Re‐Re‐CO₂H specifically afforded amyloid‐like nanofibers. These findings further allowed to achieve the fibrillation of a longer metal sequence containing three different metals ( Fmoc‐Rh‐Pt‐Re‐Re‐CO₂H ). Cyclic voltammetry of the fibrillated Fmoc‐Re‐Re‐CO₂H demonstrated that the redox activity of the metal complexes in the sequence is preserved in the nanofibrous forms.     

Synthesis of a novel azapseudodisaccharide related to allosamidin employing N,N''-diacetylchitobiose as a key starting material

Design and synthesis of a potential chitinase inhibitor 4, related to allosamidin (2), is described. Radical cyclization mediated by tributyltin hydride was applied for the first time to chitobiose-derived oxime ethers 9a,b to give four stereoisomers of an aminocyclopentane derivative connected to an N-acetyl-D-glucosamine residue at C-1 position. The major isomer 10b was efficiently converted into a novel pseudodisaccharide 4 via a series of cyclic-guanidine formation reaction.