bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of maleated styrene–(ethylene‐co‐butene)–styrene on the morphology and mechanical and thermal properties of polystyrene/polyamide 1212 blends
Authors: Li Yulin , Xie Tingxiu , Yang Guisheng
Published: January 2005

Polystyrene (PS)/polyamide 1212 (PA 1212) blends were compatibilized with a maleated triblock copolymer of styrene–(ethylene‐co‐butene)–styrene (SEBS‐g‐MA). Scanning electron microscopy revealed that the addition of SEBS‐g‐MA was beneficial to the dispersion of PA 1212 in the PS matrix because of the reaction between them. The variation of the fraction of SEBS‐g‐MA in the blends allowed the manipulation of the phase structure, which first formed a sheetlike structure and then formed a cocontinuous phase containing PA 1212/SEBS‐g‐MA core–shell morphologies. As a result, the mechanical properties, especially the Charpy notched impact resistance, were significantly improved with the addition of SEBS‐g‐MA. Differential scanning calorimetry (DSC) data indicated that the strong interaction between SEBS‐g‐MA and PA 1212 in the blends retarded the crystallization of PA 1212. The heat distortion temperature of the compatibilized blends was improved in comparison with that of the unmodified blend, probably because of the apparent increase in the glass‐transition temperature with an increasing concentration of SEBS‐g‐MA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1354–1360, 2005
Influence of the synthesis conditions on the curing behavior of phenol–urea–formaldehyde resol resins
Authors: He Guangbo , Yan Ning
Published: January 2005

The curing behavior of synthesized phenol–urea–formaldehyde (PUF) resol resins with various formaldehyde/urea/phenol ratios was studied with differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The results indicated that the synthesis parameters, including the urea content, formaldehyde/phenol ratio, and pH value, had a combined effect on the curing behavior. The pH value played an important role in affecting the shape of the DSC curing curves, the activation energy, and the reaction rate constant. Depending on the pH value, one or two peaks could appear in the DSC curve. The activation energy was lower when pH was below 11. The reaction rate constant increased with an increase in the pH value at both low and high temperatures. The urea content and formaldehyde/phenol ratio had no significant influence on the activation energy and rate constant. DMA showed that both the gel point and tan δ peak temperature (Ttanδ) had the lowest values in the mid‐pH range for the PUF resins. A different trend was observed for the phenol–formaldehyde resin without the urea component. Instead, the gel point and Ttanδ decreased monotonically with an increase in the pH value. For the PUF resins, a high urea content or a low formaldehyde/phenol ratio resulted in a high gel point. The effect of the urea content on Ttanδ was bigger than that on the gel point because of the reversible reaction associated with the urea component. Too much formaldehyde could lead to more reversible reactions and a higher Ttanδ value. The effects of the synthesis conditions on the rigidity of the cured network were complex for the PUF resins. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1368–1375, 2005
Rheological and thermal properties of single‐site polyethylene blends
Authors: Chen Fei , Shanks Robert A. , Amarasinghe Gandara
Published: January 2005

Branched polyethylenes, low‐density polyethylenes (LDPE1 and LDPE2) or long‐chain‐branched very low density polyethylenes (VLDPE2), were blended with very low density polyethylenes containing short branches (VLDPE1 and VLDPE3). The rheological and thermal measurements of the pure copolymers and their blends (VLDPE1–LDPE1, VLDPE1–LDPE2, VLDPE1–VLDPE2, and VLDPE2–VLDPE3) were taken by controlled stress rheometry and differential scanning calorimetry, respectively. The shear‐thinning effect became stronger with increasing long‐chain‐branched polymer compositions when it was correlated with the flow behavior index, and the extent of shear thinning was different for each blend set. Stronger shear thinning and a linear composition dependence of the zero‐shear viscosity were observed for the VLDPE1–LDPE1 and VLDPE1–LDPE2 blends. These blends followed the log additivity rule, and this indicated that they were miscible in the melt at all compositions. In contrast, a deviation from the log additivity rule was observed for the VLDPE1–VLDPE2 blend compositions with 50% or less VLDPE2 and for the VLDPE3–VLDPE2 blends with 50% or more VLDPE2. The thermal properties of the blends were consistent with the rheological properties. VLDPE1–LDPE1 and VLDPE1–LDPE2 showed that these blends were characteristic of a single‐component system at all compositions, whereas the phase separation (immiscibility) was detected only for VLDPE1–VLDPE2 blends with 50% or less VLDPE2 and for VLDPE3–VLDPE2 blends with 50% or more VLDPE2. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1549–1557, 2005
Morphology and mechanical properties of polyamide 12 blends with styrene/ethylene–butylene/styrene rubbers with and without maleation
Authors: Jose S. , Thomas S. , Lievana E. , Karger‐Kocsis J.
Published: January 2005

Blends of polyamide 12 (PA12) with styrene/ethylene–butylene/styrene (SEBS) and maleic anhydride grafted SEBS (SEBS‐g‐MA) were prepared by twin‐screw extrusion and injection molding. The morphology, mechanical properties, and dynamic mechanical properties of the blends were studied. The morphology of the blends was evaluated from the etched surfaces of cryogenically fractured specimens with scanning electron microscopy. The morphological parameters showed that the PA12/SEBS‐g‐MA blends (PM series) exhibited a finer and more uniform rubber dispersion than the PA12/SEBS blends (PS series) because of the interfacial chemical reactions. SEBS functionalization via maleic anhydride grafting strongly affected the morphological parameters, such as the domain size, interfacial area per unit of volume, and critical interparticle distance, but the distribution of the rubber domains in the blends was less affected. Tensile and impact studies showed that the PS blends had worse mechanical properties than the PM blends. The tensile strength and elongation at break of the PM blends were considerably greater than those of the PS blends. The fracture toughness and energy values determined for notched Charpy specimens in high‐speed impact tests were markedly higher for the PM blends than for the PS blends. A similar observation was obtained from instrumented falling weight impact studies. Dynamic mechanical analysis confirmed the incompatibility of the blend components because the glass‐transition temperatures of PA12 and the rubber phase (SEBS and SEBS‐g‐MA) were not affected. © 2005 Wiley Periodicals, Inc. J Appl polym Sci 95: 1376–1387, 2005
Thermal switching of the actuation ability of an electroactive polymer actuator
Authors: Watanabe Masashi , Wakimoto Naoko , Hirai Toshihiro , Yokoyama Mikito
Published: January 2005

Electroactive polymer actuators have the simple ability to be actuated by a voltage. In this study, we added a new function: the ability to be actuated by temperature. We used a bending‐electrostrictive actuator made of a polyurethane film. The polyurethane was designed to be rigid at room temperature but to be flexible at temperatures greater than 40°C because of the melting of the soft segment in the polyurethane. Therefore, the actuator showed slight bending in response to a voltage at room temperature. However, it showed significant bending at 61°C. The degree of bending at 61°C was 29 times greater than that at 13°C. Thus, the actuation ability was switched on at 61°C but switched off at 13°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1566–1570, 2005
Properties and structure of PVP–lignin “blend films”
Authors: Liu Changhua , Xiao Chaobo , Liang Hui
Published: January 2005

Blend films of poly (4‐vinylpyridine) and lignin were prepared by the casting method. Their structure and properties were studied by Fourier transform infrared (FTIR), wide‐angle X‐ray diffraction (WXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), and differential scanning calorimetry (DSC). The IR spectra of the blend films indicated that hydrogen‐bonding interaction occurred between poly (4‐vinylpyridine) and lignin. The glass transition temperature of these blends increased with the increase of lignin content, which indicated that these blends were able to form a miscible phase due to the formation of intermolecular hydrogen bonding between the hydroxyl of lignin and the pyridine ring of poly (4‐vinylpyridine). The thermostability of these blends decreased with the increase of lignin content. Initially, an appreciable increase in the measured tensile strength was achieved with a lignin content of 15%, at which the maximum value of 33.03 MPa tensile strength was reached. At a 10% lignin incorporation level, the blend film exhibited a maximum value of 9.03% strain. When the threshold in lignin content for blend films exceeded that limit of 10% lignin, the strain behavior of these blend films deteriorated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1405–1411, 2005
Monodisperse‐porous poly(styrene‐co‐divinylbenzene) beads providing high column efficiency in reversed phase HPLC
Authors: Unsal E. , Elmas B. , Çamlı S. T. , Tuncel M. , Şenel S. , Tuncel A.
Published: January 2005

A multistage polymerization protocol, the so‐called “modified seeded polymerization,” was developed for the production of monodisperse‐porous poly(styrene‐co‐divinylbenzene) providing high column efficiency as a packing material in reversed phase high performance liquid chromatography (RPLC). In the first stage of the multistage production, uniform polystyrene seed particles, produced by dispersion polymerization, were swollen by an organic agent (i.e., the diluent) and then by a monomer mixture containing styrene and divinylbenzene. The final porous particles were obtained in the monodisperse form by the polymerization of monomer mixture in the seed particles. By the use of a small size seed latex with low molecular weight and by the selection of the appropriate diluent, relatively small monodisperse‐porous particles with suitable pore structure could be achieved. In the reversed phase separation of alkylbenzenes, under isocratic conditions, theoretical plate numbers up to 40,000 plates/m were achieved by using 5.2 μm porous particles, obtained by a toluene‐dibutyl phthalate mixture as the diluent. No significant decrease in the resolution power was observed by the fourfold increase in the mobile phase flow rate. The column efficiency and the resolution observed with 5.2 μm monodisperse‐porous particles were significantly higher with respect to the currently available polymer based packing materials used in the reversed phase HPLC. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1430–1438, 2005
Preparation of syndiotactic polystyrene/montmorillonite nanocomposites via in situ intercalative polymerization of styrene with monotitanocene catalyst
Authors: Shen Zhigang , Zhu Fangming , Liu Dan , Zeng Xiguo , Lin Shangan
Published: January 2005

Syndiotactic polystyrene (sPS)/montmorillonite nanocomposites were prepared via in situ intercalative coordination polymerization using mono‐(η5‐pentamethylcyclopenta‐ dienyl) tribenzyloxy titanium [Cp*Ti(OBz)3] complex activated by methylaluminoxanes (MAO) and triisobutylaluminum (TIBA). The influences of polymerization conditions, such as the weight ratio of montmorillonite and styrene, temperature, and monomer concentration, on the preparation of sPS/montmorillonite nanocomposites was investigated. The intercalation spacing in the nanocomposites, as well as the exfoliation of the montmorillonite interlayers, was characterized with wide angle X‐ray diffraction (WAXD) and transmission electron microscopy (TEM). The dispersibility of the nanoscale elements depended on the polymerization conditions and the surfactant treatment. The crystallizability and thermal properties of these nanocomposites were determined by differential scanning calorimetry (DSC) analysis and thermogravimetric analysis (TGA). Experimental results indicated that the degree of crystallinity of the sPS nanocomposite increased with increasing montmorillonite content and with higher Tg and thermal decomposition temperature than pure sPS. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1412–1417, 2005
Kinetic approach on stabilization of LDPE in the presence of carnosic acid and related compounds. I. Thermal investigation
Authors: Jipa S. , Zaharescu T. , Setnescu R. , Gorghiu L. M. , Dumitrescu C. , Santos C. , Silva A. M. , Gigante B.
Published: January 2005

Carnosic acid and similar compounds exhibit antioxidant behavior in a polyethylene matrix. Thermal resistance of LDPE was investigated at three temperatures (190, 200, and 210°C) by isothermal chemiluminescence. The main kinetic parameters: oxidation induction period (ti), half oxidation time (t1/2), maximum oxidation time (tmax), and propagation rate of oxidation (voxmax) were calculated. The inhibition of thermal degradation is proved by the values of these parameters relative to unstabilized polymer: the induction times of stabilized low density polyethylene are of one order of magnitude greater that raw polyethylene, and half oxidation periods are three to five times longer than initial LDPE. Thermal aging of protected low density polyethylene occurs at a much slower rate in comparison with unmodified LDPE. The depletion of stabilizers was also evaluated and the kinetic characteristics (the half‐life and the rate constant of consumption for each antioxidant) at three concentrations of all tested additives (0.125, 0.25, 0.50, and 0.75% w/w) were determined. The effectiveness of stabilization was depicted by two values of activation energies calculated from oxidation induction times and maximum oxidation periods. Some considerations on stabilizing mechanism are presented. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1571–1577, 2005
Strength of materials and elasticity approach to stiffness of fibrous composites using the concept of interphase
Authors: Sideridis E. , Papadopoulos G. A. , Kyriazi E.
Published: January 2005

A strength of materials and elasticity approach was used in this study to determine the stiffness of fiber‐reinforced composites, by taking into account the concept of boundary interphase. Theoretical expressions for longitudinal transverse and shear moduli, as well as for longitudinal Poisson's ratio, were derived by use of this model. Results derived from these expressions were compared with others, to observe the discrepancies and evaluate their validity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1578–1588, 2005
Effect of reaction parameters on the structure and properties of acrylic rubber/silica hybrid nanocomposites prepared by sol‐gel technique
Authors: Bandyopadhyay Abhijit , Sarkar Mousumi De , Bhowmick Anil K.
Published: January 2005

The effects of a few reaction parameters, namely, type of solvents, tetraethoxysilane (TEOS)‐to‐water mole ratio, and temperature of gelation at constant concentration of TEOS (45 wt %) and pH of 1.5 were investigated for acrylic rubber/silica hybrid nanocomposites prepared by sol‐gel technique. Infrared spectroscopic studies indicated the maximum silica generation within the system when tetrahydrofuran was used as the solvent for the sol‐gel reaction. The distribution of the silica particles (average dimension 100 nm) forming a network type of structure within the composite was confirmed by scanning electron microscopic studies (SEM). The other solvents studied here produced a lower amount of silica because of either high polarity of the solvents (methyl ethyl ketone and dimethyl formamide) or their limited miscibility with water (for ethyl acetate). An increase in the proportion of water caused silica agglomeration. Energy dispersive X‐ray analysis (EDAX) silicon mapping also demonstrated the existence of agglomerated silica structures at high TEOS‐to‐water mole ratio (>2). Higher temperature for gelation of the composites caused the aggregation of silica particles. The uncured composites containing nanolevel (<90 nm) dispersion of silica particles demonstrated slightly higher storage modulus, lower value of tan δmax, and higher glass transition temperature compared to the composites with silica particles of a larger dimension (>2 μm). Improvement in tensile strength and modulus was observed in the uncrosslinked as well as in the crosslinked state (cured by a mixed crosslinking system of hexamethylenediamine carbamate and ammonium benzoate). However, the extent of improvement in strength and modulus for the nanocomposites was higher (247 and 57%, respectively) compared to the microcomposite (150 and 27%, respectively) in the cured state. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1418–1429, 2005
Phase‐separation mechanism and corresponding final morphologies of thermoset blends based on unsaturated polyester and low‐molar‐weight saturated polyester
Authors: Boyard N. , Vayer M. , Sinturel Ch. , Erre R.
Published: January 2005

The final morphology of cured blends based on unsaturated polyester, styrene, and low‐molar‐weight saturated polyester as a low profile additive (LPA) was investigated with atomic force microscopy and scanning electron microscopy. The observed structure was compared to those obtained with widely used poly(vinyl acetate) (PVAc). On the surface and in the bulk, a network of particles, ranging in size from 50 to 60 nm, was observed with saturated polyester as an LPA. The influence of the molar weight and LPA content was investigated. To determine the mechanism of formation of such a morphology, in situ experiments were carried out to elucidate the phase‐separation mechanism. Small‐angle laser light scattering and small‐angle neutron scattering experiments were performed on ternary blends containing PVAc and saturated polyester, respectively. The first stage of spinodal decomposition was observed in both cases. Within our experimental conditions, gelation froze further evolution and led to a two‐phase cocontinuous structure that imposed the final morphology characteristics. In particular, the period and amplitude of the concentration fluctuations generated during the phase separation played essential roles. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1459–1472, 2005
Spectrophotometric investigation of laser dye diffusion in styrene–acrylonitrile copolymer solutions
Authors: Rao K. Chowdoji , Rao K. S. V. Krishna , Mallikarjuna N. N. , Naidu B. Vijaya Kumar , Aminabhavi Tejraj M.
Published: January 2005

An ultraviolet spectrometer was used to measure the absorption kinetics of a laser dye, 1,4‐bis(5‐phenyloxazoyl‐2‐yl) benzene, at its maximum wavelength in solutions of styrene–acrylonitrile copolymer dissolved in 1,4‐dioxane. From the time‐dependent absorbance data, the dye diffusion coefficient was calculated by a combination of Fick's law of diffusion with the Beer–Lambert law of absorption. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1481–1484, 2005
Mechanical properties of copper‐clad laminate using composite naphthalene–phenyl‐based epoxy as prepreg
Authors: Duann Yeh‐Fang , Chen Bor‐Lin , Tsai Teh‐Hua
Published: January 2005

A composite was prepared that contained diglycidyl ether of tetrabromobisphenol A (DGETBA) and 1,5‐di(2,3‐epoxypropoxy)naphthalene (A), 4,4′‐bis(2,3‐epoxypropoxy)benzylideneaniline (B), or 4,4′‐bis(2,3‐epoxypropoxy)biphenyl (C), and then was cured using different ratios of dicyandiamide (DICY). The results of DSC, TGA, coefficient of thermal expansion, dielectric constant, and dissipation factor testing of the composite epoxy resins were analyzed, and investigation of the copper‐clad laminate using the composite epoxy resins as prepreg was also performed. Additionally, moisture absorption, peel strength, arc resistance, comparative tracking index, and flammability of the copper‐clad laminate were examined. Clearly, some of the physical or mechanical properties of the composite and the copper‐clad laminate can be improved by optimal addition of naphthalene–phenyl‐based epoxy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1485–1492, 2005
Photofabrication of biofiber‐based polymer matrix composites
Authors: Kumar R. N. , Hee Khoo Chin , Rozman H. D.
Published: January 2005

The novel development of a photofabrication process of biofiber composites, based on oil palm empty fruit bunch fibers, is reported. The process consists of the following steps: (1) the preparation by a wet process of nonwoven mat of biofiber, either alone or in combination with glass and nylon; (2) drying the mat; (3) preparation of photocurable resin matrix, consisting of vinyl ester and photoinitiator; (4) impregnation of the mat by photocurable resin; and (5) irradiation of the impregnated mat by UV radiation to effect the cure of the composite. The nonwoven mat was formed in a “headbox” into which was poured a slurry of fibers. A wet mat was formed by after dewatering of the slurry. Biofiber, glass, and nylon fibers were mixed in different proportions. A “mixture experimental design” was used to generate experimental compositions of the reinforcing fibers and to model dependency of the response variables on the components through mathematical relationships. These relationships were meant to (1) determine the effect of composition of the reinforcing fibers on the physical and mechanical properties, (2) predict the response for any unknown composition of fibers, and (3) determine the optimum values of any identified properties. Because the product was characterized by multiple responses, simultaneous maximization of all properties was not feasible. The product must be considered in the definition of the trade‐off or compromise of properties to obtain overall satisfactory performance. Such an optimization was carried out and the results are reported. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1493–1499, 2005
Kinetic study of the thermal decomposition of (2‐phenyl‐1,3‐dioxolane‐4‐yl) methyl methacrylate and 2‐hydroxyethyl methacrylate copolymers
Authors: Ceylan Nilgün Neşe , İlter Zülfiye , Ceylan Kadim
Published: January 2005

The kinetics of nonisothermal decomposition of (2‐phenyl‐1,3‐dioxolane‐4‐yl) methyl methacrylate (PDMMA), 2‐hydroxyethyl methacrylate (HEMA), and vinyl‐pyrrolidone (VPy) copolymers were investigated by thermogravimetry (TG) and differential thermal analysis (DTA). The data indicated that the major weight loss occurs in the range of 270 to 450°C. The decomposition characteristics showed essentially two regimes and varied depending on the temperature and the copolymer composition. The apparent kinetic parameters of the decompositions were estimated from both TG and DTA data by using the alternative calculation methods. The results suggest that the weight loss rates may be represented, depending on the type of sample, by a reaction model of overall order 1.0 to 1.6, with an activation energy of approximately 65–95 kJ mol−1. The DTA data estimated considerably higher values for the overall activation energies, around 198–240 kJ mol−1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1500–1508, 2005
Thermal stability of chemically crosslinked moisture‐cured polyurethane coatings
Authors: Chattopadhyay D. K. , Sreedhar B. , Raju K. V. S. N.
Published: January 2005

Polyurethane prepolymers are widely used in reactive hot melt adhesives and moisture‐cured coatings. The segmented moisture‐cured formulations, based on polytetramethylene glycol (PTMG‐1000)/trimethylol propane (TMP)/isophorone diisocyanate (IPDI) and PTMG/TMP/toluene diisocyanate (TDI), were prepared with NCO/OH ratio of 1.6 : 1.0. The excess isocyanate groups of the prepolymers were chain extended in the ratio of 2 : 1 (NCO/OH) with different aliphatic diols and 4 : 1 with different aromatic diamines. The surplus isocyanate groups of the formulations were completely reacted with atmospheric moisture, and the thermal stability of the postcured materials obtained as cast films were evaluated by thermogravimetric (TG) analysis. It was observed that initial degradation temperatures were above 270°C, with two‐ or three‐step degradation profiles. The degradation parameters were evaluated using the Broido and Coats–Redfern methods. The thermal resistance of moisture‐cured formulations using diisocyanates with the cycloaliphatic structures (IPDI) and the aromatic TDI, at the same NCO/OH ratio (1.6), and TMP content were compared from the isothermal TG experiments at different temperatures and dynamic TG experiments at different heating rates in nitrogen and oxygen environments. The observation suggests that polyurethane‐containing sulfone groups and straight‐chain diol chain extenders were more stable. It was also observed that at lower temperature polyurethane, prepared from aliphatic diisocyanates (IPDI), was more stable than the aromatic diisocyanate (TDI) containing polyurethanes. At high temperature, the stability order follows the reverse trend. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1509–1518, 2005
Investigation of 5‐FU disposition after oral administration of capecitabine, a triple‐prodrug of 5‐FU, using a physiologically based pharmacokinetic model in a human cancer xenograft model: comparison of the simulated 5‐FU exposures in the tumour tissue between human and xenograft model
Authors: Tsukamoto Yuko , Kato Yukio , Ura Masako , Horii Ikuo , Ishikawa Tohru , Ishitsuka Hideo , Sugiyama Yuichi
Published: January 2005

The nonlinear pharmacokinetics of capecitabine, a triple prodrug of 5‐FU preferentially activated in tumour tissues, was investigated in human cancer xenograft models. A physiologically based pharmacokinetic (PBPK) model integrating the activation process of capecitabine to 5‐FU and 5‐FU elimination was constructed to describe the concentration/time profiles of capecitabine and its three metabolites, including 5‐FU, in blood and organs. All the biochemical parameters (enzyme kinetic parameters, plasma protein binding and tissue binding of capecitabine and its metabolites) integrated in this model were measured in vitro. The simulated curves for the blood and tumour concentrations of capecitabine and its metabolites can basically describe the observed values. A simple prodrug of 5‐FU, doxifluridine, is known to be activated to 5‐FU to some extent in the gastrointestinal (GI) tract, causing diarrhoea, which is the dose limiting side effect of doxifluridine. Consequently, the therapeutic index (the ratio of 5‐FU AUC in the tumour to that in GI) after the administration of effective dose capecitabine was predicted by this PBPK model and found to be five times and 3000 times greater than that of doxifluridine and 5‐FU, respectively. This was compatible with the previous result for the difference in the ratio of the toxic dose to the minimum effective dose between capecitabine and doxifluridine, suggesting that 5‐FU preferentially accumulates in tumour tissue after oral administration of capecitabine compared with the other drugs (doxifluridine and 5‐FU). The 5‐FU AUC in tumour tissue of human cancer xenograft models at the minimum effective dose was comparable with those estimated for humans at the clinical dose. In addition, the predicted therapeutic indices at the respective doses were correlated well between humans and mice (xenograft model). These results suggest that the 5‐FU AUC in human tumour tissue at its clinically effective dose can be predicted based on the PBPK model inasmuch as the 5‐FU AUC in a human cancer xenograft model at its effective dose may be measured or simulated. Copyright © 2001 John Wiley & Sons, Ltd.
Transcellular transport of genistein, a soybean‐derived isoflavone, across human colon carcinoma cell line (Caco‐2)
Authors: Oitate Masataka , Nakaki Rie , Koyabu Noriko , Takanaga Hitomi , Matsuo Hirotami , Ohtani Hisakazu , Sawada Yasufumi
Published: January 2005

Genistein, a soybean‐derived isoflavone, is thought to have an anticarcinogenic action, but little is known about the cellular mechanisms of its intestinal absorption. This study was designed to investigate the absorption mechanisms of genistein using human colon carcinoma cell line, Caco‐2 cells. The apical‐to‐basolateral transcellular transport of genistein across a Caco‐2 cell monolayer was significantly greater than that in the opposite direction. An uptake experiment revealed that cellular uptake of genistein by Caco‐2 cells was concentrative. The transcellular transport of genistein was saturable and temperature‐dependent, and was inhibited by other flavonoids such as rutin, quercetin, (+)‐catechin and (−)‐epicatechin. These results suggest that genistein is transported across Caco‐2 cells by a carrier‐mediated system, located on the apical membrane. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of smoking on single dose pharmacokinetics of phenobarbital
Authors: Mirfazaelian A. , Jahanzad F. , Tabatabaei‐far M. , Farsam H. , Mahmoudian M.
Published: January 2005

In order to determine interaction of smoking with single dose pharmacokinetics of phenobarbital, a 60 mg tablet of the drug was given to 12 healthy male subjects in two groups (6 smokers and 6 non‐smokers) in a double blind study. An HPLC method using UV detection was developed to assess phenobarbital in plasma of the subjects. Pharmacokinetic parameters were calculated and compared in the two groups. Pharmacokinetic parameters of the two groups were not significantly different in the two groups (p<0.05). The results show no considerable effect of cigarette smoking on phenobarbital pharmacokinetics, which is in agreement with enzyme studies performed previously. Copyright © 2001 John Wiley & Sons, Ltd.
Angiotensin II receptor antagonist treatment during pregnancy
Authors: Alwan S. , Polifka J.E. , Friedman J.M.
Published: January 2005

Angiotensin II (A‐II) is the main effector of the renin‐angiotensin system. A‐II functions by binding its type 1 (AT1) receptors to cause vasoconstriction and retention of sodium and fluid. Several AT1 receptor antagonists—a group of drugs collectively called “sartans”—have been marketed during the past few years for treatment of hypertension and heart failure. At least 15 case reports describe oligohydramnios, fetal growth retardation, pulmonary hypoplasia, limb contractures, and calvarial hypoplasia in various combinations in association with maternal losartan, candesartan, valsartan, or telmisartan treatment during the second or third trimester of pregnancy. Stillbirth or neonatal death is frequent in these reports, and surviving infants may exhibit renal damage. The fetal abnormalities, which are strikingly similar to those produced by maternal treatment with angiotensin‐converting enzyme (ACE) inhibitors during the second and third trimesters of pregnancy, are probably related to extreme sensitivity of the fetus to the hypotensive action of these drugs. Very little information is available regarding the outcome of human pregnancies in which the mother was treated with an AT1 receptor antagonist during the first trimester, but animal studies have not demonstrated teratogenic effects after maternal treatment with large doses of AT1 receptor antagonists during organogenesis. We conclude that pharmacological suppression of the fetal renin‐angiotensin system through ACE inhibition or AT1 receptor blockade seems to disrupt fetal vascular perfusion and renal function. We recommend that maternal treatment with AT1 receptor antagonists be avoided during the second and third trimesters of pregnancy and that women who become pregnant while taking one of these medications be changed to an antihypertensive drug of a different class as soon as the pregnancy is recognized. Birth Defects Research (Part A) 73, 2004. © 2004 Wiley‐Liss, Inc.
Analysis of lonidamine in rat serum and testis by high performance liquid chromatography
Authors: Grippa Eleonora , Gatto Maria Teresa , Leone Maria Grazia , Tita Beatrice , Adbel‐Haq Hanin , Vitalone Annabella , Silvestrini Bruno , Saso Luciano
Published: January 2005

A HPLC method for the determination of lonidamine in serum and testis, suitable for pharmacological studies in the rat and other mammals, has been developed. Briefly, 0.5 mL of serum or about 0.2 g of testicular tissue were extracted with ethyl acetate and evaporated to dryness under nitrogen. The residue was redissolved in methanol and an aliquot was injected onto a C18 column eluted with a mobile phase consisting of acetonitrile:water (51:49, v/v), containing 0.1% trifluoroacetic acid. The eluate was monitored at 230 nm with a sensitivity of 0.05 AUFS. By this method, the pharmacokinetics and the serum and testicular levels of the drug up to 120 h after the administration of one single dose (100 mg/kg body weight) of lonidamine to Sprague–Dawley rats have been studied. Results were highly variable, as previously reported, but a very good linear correlation was found between the serum and the testicular levels, suggesting that, in the rat, and possibly in the human, testicular levels could be estimated based on the serum concentrations. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

ACN

acetonitrile

AUFS

absorbance units at full scale;

bw

body weight;

CV

coefficient(s) of variation;

EA

ethyl acetate;

HPLC

high performance units at full scale;

F

flurbiprofen;

LND

lonidamine;

NRS

normal rat serum;

NRT

normal rat testes;

NRTC

normal rat testicular cytosol;

P

peak area;

QC

quality controls;

S

serum;

TC

testicular cytosol;

TFA

trifluoroacetic acid.
Phenotype analysis of cytochrome P450 2C19 in Chinese subjects with mephenytoin S/R enantiomeric ratio in urine measured by chiral GC
Authors: Yao, T. W. , Zeng S. , Wang T. W. , Chen S. Q.
Published: January 2005

A chiral gas chromatographic method with FID was developed for the determination of S‐ and R‐mephenytoin in human urine. The assay is linear from 25 to 800 ng/mL for each enantiomer and the limit of detection and limit of quantitation were 12 and 25ng/mL for each enantiomer, respectively. The method affords average recoveries of 74.41 ± 3.93% and 73.78 ± 3.02% for S‐ and R‐mephenytoin, respectively. The method allows the phenotype study of CYP2C19 in Chinese subjects. The phenotype pattern of 90 Chinese volunteers was determined, in which 26 volunteers received phenotyping and genotyping tests. The results of phenotype analysis showed that the interindividual variation was marked. The mephenytoin S/R enantiomeric ratios in urine of 11 volunteers were ≥0.95 and identified as poor metabolizers. The frequency of poor metabolizers was 12.2% in the Chinese subjects tested. A good relationship between phenotype and genotype analysis of CYP2C19 was observed. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

EM

extensive metabolizer

MP

mephenytoin

PM

Poor metabolizer
Determination of unbound cefamandole in rat blood by microdialysis and microbore liquid chromatography
Authors: Yeh Pen‐Ho , Lee Chi‐Hui , Cheng Fu‐Chou , Tsai Tung‐Hu
Published: January 2005

To analyze unbound cefamandole in rat blood, a method combing microdialysis with microbore liquid chromatography has been developed. A microdialysis probe was inserted into the jugular vein/right atrium of male Sprague–Dawley rats to examine the unbound cefamandole level in the rat blood following cefamandole administration (50 mg/kg, i.v.). The dialysates were directly submitted to a liquid chromatographic system. Samples were eluted with a mobile phase containing acetonitrile–methanol–100 mM monosodium phosphate (pH 5.0; 15:20:65, v/v). The UV wavelength was set at 270 nm for monitoring the analyte. Using the retrograde method, at infusion concentrations of 1 µg/mL of cefamandole, the in vivo microdialysis recoveries were 55.44% for the rat blood (n = 6). Intra‐ and inter‐assay accuracy and precision of the analyses were ≤10% in the range of 0.1–10 µg/mL. Pharmacokinetic parameters were calculated from the recovery‐corrected dialysate concentrations of cefamandole vs time data. The elimination half‐life (t1/2,β) was 21.6 ± 1.6 min. The results suggest that the pharmacokinetics of unbound cefamandole in blood following cefamandole administration (50 mg/kg, i.v., n = 5) fit best to the two‐compartmental model. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

RSD

relative standard deviation
Combination of HPLC and solid‐phase binding assay for isolation and purification of MHC class I and associated peptides using a bladder tumour cell line
Authors: Torabi‐Pour N. , Nouri A. M. E. , Perrett D. , Oliver R. T. D.
Published: January 2005

The major histocompatibility complex (MHC) class I molecules present processed self and non‐self peptides to T lymphocytes. Given that the class I peptide complex plays a critical role in cell‐mediated immunity, it is important to identify the nature of class I‐associated peptides unique to malignant cells as a prelude to the development of vaccines. The aim of this study was to combine immuno‐bead purification (using anti‐class I antibody W6/32) technique, sequential ultra‐filtration and high performance liquid chromatography (HPLC) to isolate class I antigens and associated peptides from an in‐house established bladder tumour cell line (Fen) whose missing class I antigens had been restored by β2‐microglobulin (β2‐m) gene transfaction. The results were as follows: (a) class I antigens could be separated from tumour cell lysate but only from the class I positive Fen cells; (b) treatment of CNBr‐W6/32 beads pre‐exposed to class I positive Fen lysate and eluted with dissociation agent (mild acid) resulted in the release of more than 20 peptides at an approximate molecular weight of between 700 and 3000 Da based on SDS–PAGE and silver staining analysis; (c) purified and eluted peptides from class I antigens showed distinct peaks when analysed by HPLC. The data presented in this investigation demonstrated the feasibility of isolating class I antigens and associated peptides from a bladder tumour cell line. The extension of these approaches to isolate peptides from tissue tumour biopsies may help the future of vaccine therapy in cancer patients. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

FCS

foetal calf serum

MHC

major histo compatibility complex

PAGE

polyacrylamide gel electrophoresis

RP

reverse‐phase

SDS

sodium dodecyl sulphate.
Separation of chiral 4‐substituted imidazole derivatives by cyclodextrin‐modified capillary electrophoresis†
Authors: Sasse Astrid , Schunack Walter , Stark Holger
Published: January 2005

Enantiomeric separations by cyclodextrin‐modified capillary electrophoresis of chiral carbamates containing a 4‐substituted imidazole heterocycle, pharmacologically acting as histamine H3‐receptor antagonists, were carried out. Various cyclodextrins (α‐, β‐ and substituted β‐cyclodextrins) were investigated. Baseline resolution was achieved with six out of 11 compounds. Heptakis‐2,3,6‐trimethyl‐β‐cyclodextrin modified buffers seemed to be most efficient in separating most of the investigated compounds. The optical purity of one pair of enantiomers was determined. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

α‐CD

α‐cyclodextrin

β‐CD

β‐cyclodextrin

CD

cyclodextrins

CE

capillary electrophoresis

CM‐β‐CD

carboxymethylated‐β‐cyclodextrin

DM‐β‐CD

heptakis‐2,6‐dimethyl‐β‐cyclodextrin

DS

average degree of substitution

ee

enantiomeric excess

HE‐β‐CD

2‐hydroxyethyl‐β‐cyclodextrin

HP‐β‐CD

2‐hydroxypropyl‐β‐cyclodextrin

i.d.

inner diameter

LOD

limit of detection

LOQ

limit of quantification

Rs

resolution

SBE‐cd

sulphobutylether‐β‐cyclodextrin

SO4‐β‐CD

sulphated‐β‐cyclodextrin

TM7hyphen;β‐CD

heptakis‐2,3,6‐trimethyl‐β‐cyclodextrin
An LD50 model for predicting psychotropic drug toxicity using biopartitioning micellar chromatography
Authors: Quiñones‐Torrelo C. , Sagrado‐Vives S. , Villanueva‐Camañas R. M. , Medina‐Hernández M. J.
Published: January 2005

The LD50 determination is the main way to measure the acute toxicity of all types of substances. At the present time, however, there is increasing opposition to the use of living animals in research and testing activities from animal rights groups as well as some scientists. Nevertheless, the need to have a tool for estimating the potential toxicity of new compounds for human consumption has encouraged the development of alternative methods. Under adequate conditions, the partitioning in micellar liquid chromatography can describe the drug biopartitioning. We have named this chromatographic system biopartitioning micellar chromatography (BMC). In this paper, an LD50 QRAR model developed for psychotropic drugs from their retention data in BMC, is described. The model's ability to predict new psychotropic drug toxicity is statistically proved. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

BMC

biopartitioning micellas chromatography

QRAR

quantitative retention–activity relationships

QSAR

quantitative structure–activity relationships

RMSEC

root‐mean‐square error of calibration

RMSECV

root‐mean‐square error of cross‐validation.
Identification of reaction products of methamphetamine and hydrogen peroxide in hair dye and decolorant treatments by high‐performance liquid chromatography/mass spectrometry
Authors: Tanaka Seishi , Iio Reiko , Chinaka Satoshi , Takayama Nariaki , Hayakawa Kazuichi
Published: January 2005

The effect of hydrogen peroxide, a main component of hair dye and decolorant treatments, on methamphetamine (MA) was studied. Two analytical methods, thin‐layer chromatography (TLC) and high‐performance liquid chromatography/mass spectrometry (LC/MS), were used for the separation and identification of MA derivatives. Mixtures of MA solutions and hydrogen peroxide that had been incubated at 39°C for 24 h were shown to contain para‐hydroxy MA by TLC and para‐, meta‐ and ortho‐hydroxy MAs by LC/MS. In addition, MA N‐oxide and N‐hydroxy MA were found in MA/hydrogen peroxide mixtures immediately after mixing. Therefore, we concluded that MA changed to MA N‐oxide and N‐hydroxy MA before changing to para‐, meta‐ and ortho‐hydroxy MAs. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

AP

amphetamine

CID

collision‐induced dissociation

OHMA

hydroxy MA

MA

methamphetamine

TIC

total ion chromatogram
Determination of catecholamines and their 3‐O‐methyl metabolites in mouse plasma
Authors: Tsunoda Makoto , Takezawa Kazuko , Yanagisawa Teruyuki , Kato Masaru , Imai Kazuhiro
Published: January 2005

The determination of catecholamines and their 3‐O‐methyl metabolites in a single mouse plasma is necessary to understand the role of the sympathetic nervous activity, while the inactivation of catecholamines by catechol‐O‐methyltransferase indicates the activity of blood pressure regulation in animals. Here we report the basal catecholamines and their 3‐O‐methyl metabolite concentrations obtained from 15 µL of mouse plasma utilizing semi‐microcolumn high‐performance liquid chromatography (HPLC)‐peroxyoxalate chemiluminescence detection system. The concentrations were 6.63 ± 1.37 pmol/mL plasma, 0.49 ± 0.10 pmol/mL plasma, 5.25 ± 2.30 pmol/mL plasma, 3.23 ± 0.84 pmol/mL plasma, 0.44 ± 0.11 pmol/mL plasma, and 3.39 ± 1.67 pmol/mL plasma for norepinephrine, epinephrine, dopamine, normetanephrine, metanephrine and 3‐methoxytyramine, respectively (n = 5–7). Further, when blood pressure was reduced by minoxidil, plasma catecholamines were found to be significantly increased by the baroreflex‐mediated response in mouse. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

CA

catecholamine

COMT

catehol‐O‐methyltransferase

DA

dopamine

E

epinephrine

MN

metarephrines 3‐MT, 3‐methoxytyramine

NE

norepinephrine

NMN

normetanephrine

SHR

spontaneously hypertensive rats.

WKR

Wystar Kyoto rats.
Application of planar chromatography to the determination of cotinine in urine of active and passive smoking pregnant women
Authors: Tyrpień Krystyna , Bodzek Piotr , Mańka Grzegorz
Published: January 2005

A quick and economical method for the determination of nicotine and its main metabolite‐cotinine in urine from smoking and passively smoking pregnant women is proposed using TLC‐densitometry. Chromatographic separations were performed on the plates coated with silica gel bound with C‐18 alkyl chains. Chromatograms were developed using a mixture of acetonitrile and water (88 + 12, v/v) in a horizontal chamber. Visualization was carried out under UV illumination at λ = 254 nm and then cotinine was quantified by the use of densitometer in reflectance mode at λ = 260 nm. Nicotine was identified after derivatization with Dragendorff reagent under visible light. The results of nicotine and cotinine analysis were verified by questionnaires obtained from pregnant women according to their age and smoking status correlated with spontaneous abortion frequency and child death rate. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

ETS

environmental tobacco smoke exposure
Analytical method of chondroitin/dermatan sulfates using high performance liquid chromatography/turbo ionspray ionization mass spectrometry: application to analyses of the tumor tissue sections on glass slides
Authors: Oguma Toshihiro , Toyoda Hidenao , Toida Toshihiko , Imanari Toshio
Published: January 2005

We established a highly sensitive quantitative analytical method for chondroitin/dermatan sulfates by LC/MS method. By this method, the unsaturated disaccharides produced after the enzymatic digestion of chondroitin/dermatan sulfates can be determined in the amounts as low as 0.5 pmol levels. The use of tetrabutylammonium hydroxide as an ion‐pair reagent for LC/MS allowed us to separate unsaturated 4‐sulfated disaccharide and unsaturated 6‐sulfated disaccharide. Furthermore, the peak areas of unsaturated disaccharides were increased almost 10 times by the postcolumn addition of acetonitrile. We applied this LC/MS method to the analyses of unsaturated disaccharides from chondroitin/dermatan sulfates in the tissues sections on glass slides, which were prepared from MethA tumor‐bearing mice. This method brought about considerable reduction in the time distance from sample collection to preparation of analytical results. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

ΔDi‐4S

2‐acetamido‐2‐deoxy‐3‐O‐(β‐D‐gluco‐4‐enopyranosyluronic acid)‐4‐O‐sulfo‐D‐galactose

ΔDi‐6S

2‐acetamido‐2‐deoxy‐3‐O‐(β‐D‐gluco‐4‐enopyranosyluronic acid)‐6‐O‐sulfo‐D‐galactose, ΔDiHS‐NS, 2‐deoxy‐2‐sulfamino‐4‐O‐(4‐deoxy‐α‐L‐threo‐hex‐4‐enopyranosyluronic acid)‐D‐glucose

TBAOH

tetrabutylammonium hydroxide

TPAOH

tetrapropionylammonium hydroxide