bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capillary electrophoresis for therapeutic drug monitoring of antiepileptics
Authors: Kataoka Yasufumi , Makino Kazutaka , Oishi Ryozo 
Published: May 2005

AbstractWe examined the use of capillary electrophoresis for therapeutic drug monitoring of antiepileptic drugs. Micellar electrokinetic capillary chromatography (MEKC) with a diode array detector simultaneously determined concentrations of zonisamide, a new type of antiepileptic drug, and phenobarbital, phenytoin and carbamazepine, typical antiepileptic drugs, in human serum. Zonisamide levels in human serum obtained by MEKC correlated well with levels obtained by high‐performance liquid chromatography. The serum levels of phenobarbital, phenytoin and carbamazepine determined by MEKC were almost equal to those obtained by fluorescence polarization immunoassay. The reproducibility of separation and quantification with MEKC for intra‐ and inter‐day assays were appropriate. This MEKC method could provide a simple and efficient therapeutic drug monitoring method for antiepileptic drugs, especially in patients treated with a combination of zonisamide and other antiepileptic drugs. MEKC may be an attractive method for therapeutic drug monitoring, because of its specificity of separation, automation of procedure, ease of method development, low cost, small aqueous buffer amounts, speed of analysis, small injection volume and high environment‐directed performance.
Characterization of partitioning behavior of cephalosporins using microemulsion and micellar electrokinetic chromatography
Authors: Mrestani Yahya , El‐Mokdad Nasr , Rüttinger Hans H. , Neubert Reinhard 
Published: May 2005

AbstractElectrokinetic chromatography (EKC) was introduced to determine the partitioning behavior of various cephalosporins (cefpim, cefpirom, cefaloridin, cefaclor, cephalexin, cefuroxim, cefotaxim) in microemulsions (ME) and micellar (MC) systems. The partitioning behavior of cephalosporins in microemulsions was characterized calculating the capacity factor. The required parameters for the determination of the capacity factor (μaq and μme are the electrophoretic mobilities of the solutes in the aqueous phase and the microemulsion phase, μeff is the effective mobility in the microemulsion solution) were measured by EKC using cationic and anionic microemulsion systems consisting of the surfactants/n‐heptane/1‐butanol/10 mM phosphate buffer solution, pH 7.0. Electrokinetic chromatography was shown to be a useful method to quantify the partitioning behavior of drugs in oil/water microemulsion. The logarithm of the capacity factor was correlated with the logarithm of the 1‐octanol/water partitioning coefficients.
Effects of various anionic chiral selectors on the capillary electrophoresis separation of chiral phenethylamines and achiral neutral impurities present in illicit methamphetamine
Authors: Lurie Ira S. , Odeneal Norman G. , McKibben Timothy D. , Casale John F. 
Published: May 2005

AbstractIn this study, various anionic chiral selectors were investigated for the capillary electrophoresis (CE) separation of six chiral phenethylamines and three achiral neutral impurities which are commonly identified in illicit methamphetamine. Analyses were carried out at pH 8 (high osmotic flow) with untreated capillaries using 25 mMchiral surfactant or 10 mMcharged cyclodextrin. The chiral selectors included the micelle (R)‐N‐dodecoxycarbonylvaline (EnantioSelect (R)‐Val‐1)) (ES) and the cyclodextrins sulfobutyl(IV)‐ether‐β‐cyclodextrin (SBE(IV)‐β‐CD) (BSB4), SBE(VII)‐β‐CD (BSB7), SBE(XII)‐β‐CD (BSB12), SBE(IV)‐γ‐CD (GSB‐4), SBE(VII)‐γ‐CD (GSB‐7), sulfated(XI)‐α‐cyclodextrin (SU(XI)‐α‐CD (AS11), SU(VII)‐β‐CD (BS7), SU(XII)‐β‐CD (BS12) and SU(XIII)‐γ‐CD (GS13). Enantiomeric and achiral selectivity strongly depends on the size of the CD, the average degree of substitution, and the type of substitution. ES exhibits good performance for the neutral solutes, but exhibits enantiomeric selectivity only for the α‐hydroxyphenethylamines. GS13 provides the best overall enantiomeric selectivity. All fifteen solutes related to methamphetamine are simultaneously separated using BSB7.
Quality evaluation by capillary electrophoresis of amphotericin B injection after filtration through various membrane filters
Authors: Makino Kazutaka , Hirakawa Masaaki , Goto Yoko , Nakashima Kazue , Kataoka Yasufumi , Oishi Ryozo 
Published: May 2005

AbstractThe determination of amphotericin B, an antifungal agent, was developed using micellar electrokinetic capillary chromatography (MEKC) with a diode array detector. Repeatability and intermediate precision of MEKC analysis were acceptable. A high correlation was found between amphotericin B levels in pharmaceutical solutions obtained by MEKC and those by high‐performance liquid chromatography (HPLC) (r = 0.994). This MEKC method is therefore useful for the determination of amphotericin B. The concentration of amphotericin B did not significantly change after filtration through polyethersulfone (PES, 0.2 μm) and polyvinylidene difluoride (PVDF, 0.45 μm) membrane filters. When the Fungizone injection was filtered through PES (0.2 μm) and added to 5% dextrose for injection (500 mL), particulate matters larger than 10 μm decreased by 64% to a level under the standard defined by United States Pharmacopoeia (USP XXIII). PVDF filtration (0.45 μm) did not have this effect. Our results suggest that filtration of Fungizone injection through PES (0.2 μm) membrane filters is recommended for the preparation of intravenous amphotericin B fluid.
Therapeutic drug monitoring of doxorubicin in paediatric oncology using capillary electrophoresis
Authors: Hempel Georg , Schulze‐Westhoff Petra , Flege Silke , Laubrock Nora , Boos Joachim 
Published: May 2005

AbstractA method for the determination of doxorubicin and its main metabolite doxorubicinol in human plasma is described. Two different sample preparation procedures are applied depending on the expected concentration: To monitor the peak plasma levels, 10 μL of plasma are deproteinated with acetonitrile. After centrifugation, the supernatant is directly applied to the capillary by hydrodynamic injection. For the determination of lower amounts of doxorubicin and its main metabolite doxorubicinol 100 μL of plasma is extracted by liquid‐/liquid extraction with chloroform. After evaporation of the organic phase, the sample is reconstituted in acetonitrile/water (95/5 v/v) and injected into the capillary by electrokinetic injection. Idarubicin serves as the internal standard. Laser‐induced fluorescence detection with an Ar‐ion laser emitting at 488 nm and a 520 nm cut‐off filter is used for detection. The accuracy of the method was calculated to be 3.0% at higher concentrations and 15.0% at the limit of quantification. Reproducibility data are in accordance to the generally accepted criteria for bioanalytical methods. The limit of quantification is 2 μg/L, enabling us to monitor doxorubicin plasma levels for several days after application. Noninvasive blood sampling (from the fingertip) using heparinized capillaries was found to be a simple and convenient procedure and provides reproducible data. Initial results show high interindividual variability in doxorubicin peak plasma levels.
Comparison of capillary electrophoresis‐based immunoassay with fluorescence polarization immunoassay for the immunodetermination of methamphetamine using various methamphetamine antibodies
Authors: Choi Jeongeun , Kim Choonmi , Choi Myung Ja 
Published: May 2005

AbstractAn accurate and simple immunoassay using capillary electrophoresis (CE) with laser‐induced fluorescence (LIF) was performed for the detection of methamphetamine (MA) in urine. The CE‐LIF was conducted with an untreated fused‐silica column using antiserum and a tracer of fluorescein isothiocyanate (FITC)‐labeled MA. This CE‐LIF system was compared with fluorescence polarization immunoassay (FPIA) in a TDx analyzer in the photo‐check mode using the same FITC‐labeled tracer and the same antiserum. Various antibodies, not only those prepared by our own immunogens but also those from commercial sources, were screened and characterized in both assay systems with regard to sensitivity, precision, and cross‐reactivity. Both systems satisfied analytical precision and gave similar cross‐reactivity patterns. However, the CE‐LIF‐based immunoassay was approximately one order superior to FPIA in sensitivity, requiring less volume of sample, antiserum, and tracer for the assay. Considering that the FPIA system is well known to be a useful tool for screening antibodies and detecting drugs, the CE‐LIF‐based immunoassay system, which is seemingly more advantageous than the FPIA system, appears to have great power for the characterization of antibodies and for the detection of MA in urine.
In vivo monitoring of gabapentin in rats: A microdialysis study coupled to capillary electrophoresis and laser‐induced fluorescence detection
Authors: Rada Pedro , Tucci Sonia , Pérez Jackeline , Teneud Luis , Chuecos Susana , Hernández Luis 
Published: May 2005

AbstractGabapentin (GP) is a new anticonvulsant used in refractory epilepsy. Few studies have monitored the drug in vivo. We report the combination of capillary electrophoresis and laser‐induced fluorescence detection (CZE‐LIFD) with brain microdialysis and plasma ultrafiltration in an attempt to measure GP and offer an alternative technique for pharmacokinetic studies. We found that CZE‐LIFD is capable of linearly measuring 10−7–10−9 M GP in a 1 nL volume. It was also demonstrated that it is possible to monitor GP in prefrontal cortex dialysates and plasma in rats. It is concluded that the method permits in vivo monitoring of the drug in pharmacological as well as in clinical studies.
Development of a simple high‐performance capillary electrophoretic method with on‐line mode in capillary derivatization for the determination of spermidine
Authors: Oguri Shigeyuki , Tsukamoto Asako , Yura Atuko , Miho Yamazaki 
Published: May 2005

AbstractA new high‐performance capillary electrophoretic (HPCE) method with an on‐line mode in‐capillary derivatization (ICD) procedure for determinations of some amines using 20 mmol/L sodium dodecyl sulfate (SDS) ‐ 2 mmol/L o‐phthalaldehyde (OPA) ‐ 2 mmol/L N‐acetylcysteine (NAC) ‐ 20 mmol/L phosphate‐borate buffer [9] has previously been shown. Although this technique offers direct fluorescence detection of free amines without any derivatization procedures before or after HPCE separation, the presence of spermidine (Spd) is difficult to detect due to low fluorescence intensity. The purpose of this study is to improve the detection sensitivity of Spd by reoptimizing this method with regard to the run buffer; the reoptimized method was applied to the determination of Spd in human plasma. To enhance the fluorescence intensity of the Spd signal, it is effective to use the run buffer in the presence of both β‐cyclodextrin (β‐CD: 8.8 mmol/L) and NAC at high concentration (16 mmol/L). By contrast, the intensity was remarkably decreased when SDS was used in the presence of β‐CD. After ultrafiltrating (UF) spiked human plasma with Spd, UF plasma was directly analyzed using the reoptimized method. Spd peak was detected and separated from the other peaks of blank plasma. The present method gave good linearity (r = 0.999), reproducibility (3.85% coefficient of variation at 5 μmol/L level; n = 10) and specificity. The detection limit and lower limit of quantitation is for 0.2 μmol/L and 1 μmol/L, respectively.
Separation of etoposide phosphate and methotrexate by capillary zone electrophoresis using UV detection with a high sensitivity cell
Authors: Mrestani Yahya , Neubert Reinhard 
Published: May 2005

AbstractEtoposide phosphate and methotrexate are important anti‐tumor chemotherapeutic agents. Our previously presented capillary zone electrophoresis (CZE) method using a high sensitivity cell (Z‐cell) for quantitative analysis in biological media (urine, plasma) showed good precision and accuracy. The present results show that the investigation using a capillary with high sensitivity cell led to an approximately 10‐fold improvement of the detection limit compared to standard capillaries. Plasma and urine samples were analyzed by using a calibration curve for drug concentrations between 0.1 and 100 μg/mL. Good detection limits and good relative standard deviations of the migration times and of the peak areas were observed in these experiments.
A simulation model of morphological, vegetation and sediment changes in ephemeral streams
Authors: Hooke J. M. , Brookes C. J. , Duane W. , Mant J. M. 
Published: May 2005

AbstractA model to simulate channel changes in ephemeral river channels and to test the effects of hydrological changes due to climate change and[sol ]or land use change was developed under the auspices of the EU funded MEDALUS programme (Mediterranean Desertification and Land Use). The model, CHANGISM (Channel Change GIS Simulation Model), is designed to simulate the effect of channel flow events and of climate conditions on morphology, sediment and vegetation, through sequences of events and conditions, over periods of up to several decades. The modelling is based on cellular automata but with calculations for water and sediment continuity. Process rules have both deterministic and stochastic elements. An important feature of the model is that it incorporates feedback elements between each event. The main aim of the model is to indicate the likely outcomes of events and combinations of conditions. It is linked to GIS for both input and output. The modelling is based on a channel reach and state is input as GIS layers of morphology (DEM), sediment and vegetation cover and state. Other initial conditions of soil moisture, groundwater level, and overall gradient are input. Parameters for processes are read from tables and can be easily changed for successive runs of the model. The bases for decisions on process specifications are discussed in this paper. Initial tests of the operation and sensitivity of the model were made on idealized reaches. The model was then tested using data from monitored sites in SE Spain. Simulations using clearwater flow worked well but initial simulations using events with sediment loads showed some tendency for excess deposition. Further tests and modifications are taking place. Overall, the model is one of the most sophisticated that simulates the interaction of flows with sediment and vegetation and the outcomes in terms of erosion, deposition, morphology, sediment cover, vegetation cover and plant survival over periods of up to 30 years for the scale of a channel reach. Copyright © 2005 John Wiley & Sons, Ltd.
A simplified theory for generalizing results from a radiant panel rate of flame spread apparatus
Authors: Quintiere James 
Published: May 2005

AbstractExperimental results on the rate of lateral flame spread and time for piloted ignition under an externally imposed radiant flux were analyzed with a simple theroretical model. The data were developed from a radiant panel apparatus that considers a wall mounted sample with a flux distribution \documentclass{article}\pagestyle{empty}\begin{document}$ (\dot q_{\rm e} ^{\prime \prime } ) $\end{document} of 5 W cm−2 at the ignited end to 0.2 W cm−2 at the other end. It is shown that after an appropriate preheating time (flux exposure time before sample is ignited) the rate of flame spread (Vf) results can be correlated by \documentclass{article}\pagestyle{empty}\begin{document}$ V_{\rm f} - {\textstyle{1 \over 2}} = C\left( {\dot q''_{{\rm o,ig}} - \dot q_{\rm e} ^{\prime \prime } } \right) $\end{document} where C is a material ‘constant’ and \documentclass{article}\pagestyle{empty}\begin{document}$ \dot q''{\rm }_{{\rm o,ig}} $\end{document} is minimum flux for piloted ignition—also a material (and configuration) constant. An extension of this model demonstrates that Vf can also be expressed in terms of an ‘ignition temperature’ and the surface temperature of the material. Both correlations are derivable from a single flame spread experiment. Results are presented for a number of typical wood and plastic materials.
The effect of chain extenders and stabilizers on the in‐vivo stability of polyurethanes
Authors: Hergenrother Robert W. , Wabers Hugh D. , Cooper Stuart L. 
Published: May 2005

AbstractPoly(etherurethane) (PEU) and poly(etherurethaneurea) (Biomer®) films with and without antioxidant stabilizers were subcutaneously implanted into dogs and rats for up to 10 weeks. It was found that the molecular weight of the PEU films decreased over the 10‐week period, while the Biomer® films increased in molecular weight. The presence of the stabilizers resulted in less severe changes in molecular weight. Surface cracking was most pronounced on both the stabilized and nonstabilized PEU films. Stress did not have to be applied to induce the surface cracking.
Controlled release of bisphosphonate from a biodegradable implant: Evaluation of release kinetics and anticalcification effect
Authors: Golomb Gershon , Levi Matilda , Van Gelder Joel M. 
Published: May 2005

AbstractThe present investigation describes the formulation and the in vivo efficacy of prolonged controlled‐release chitosan matrices, containing the novel anticalcification agents adipoyland suberoylbisphosphonate (AdBP and SuBP). Chitosan matrices were prepared by the solvent‐cast method and the role of several factors such as polymer molecular weight (MW), crosslinking, and drug load concentration, on the release rate profile have been examined. Crosslinking of chitosan films retarded degradation rate of the polymer but not the release rate of the embedded drug. Chitosan's MW and drug load concentration did not affect drug release rate. The release kinetics of the bisacylphosphonates were characterized by initial burst‐effect and pseudo zero‐order kinetics in the following release phase. AdBP/chitosan matrices (co‐implanted subdermally in rats with the calcifiable bioprosthetic heart valve tissue) significantly inhibited tissue calcification after 15 and 30 days implantation (66.4 and 108.6 μg/mg Ca++ in comparison to 2.7 and 3.6 μg/mg Ca++, untreated and treated groups, respectively). No side effects were noted.
The effect of a thin coating of polymethylmethacrylate on the torsional fatigue strength of the cement‐metal interface
Authors: Davies Jeffrey P. , Singer Gordon , Harris William H. 
Published: May 2005

AbstractRecent studies have established that a mechanism of initiation of failure of fixation of cemented femoral components is debonding of the cement‐metal interface. Other studies have shown that the torsional forces induced by stair climbing and rising from a chair are very high. Thus, the interface between the femoral prosthesis and the bone cement in total hip arthroplasty (THA) is required to transmit high torsional loads from the metal to the cement in a cyclic shear mode many times per year. These torsional loads likely contribute to the debonding. This study evaluated the efficacy of a thin layer of polymethylmethacrylate (PMMA) precoating in increasing the torsional fatigue strength of the cement‐metal interface. Fatigue studies were performed on 15 specimens. Each specimen was tested with and without PMMA precoating. The PMMA precoat significantly and substantially increased the torsional fatigue strength of the cement‐metal interface. Thus, PMMA precoating is likely to be a clinical advantage in maintaining the long‐term integrity of the cement‐prosthesis interface.
Histological techniques for the study of the biomaterial‐tissue interface of total joint replacements — a modification for the preservation of bone cement
Authors: Fornasier V. L. , Sanders G. , Goodman S. B. 
Published: May 2005

AbstractThe methods usually employed for the histological processing of orthopaedic specimens of cemented joint arthroplasties involve treatment with methacrylate monomer and organic solvents which dissolve the polymethylmethacrylate cement. This may distort the intimate relationship of the cell layers along the surface of the interface between the bone and the cemented implant. The authors report on a technique for the processing and embedding of cemented orthopaedic implants which permits preservation of the polymethylmethacrylate cement. The method utilizes a modification of Spurr's low viscosity epoxy resin and avoids the use of solvents such as acetone. Undecalcified sections of cemented joint replacements from animal studies and human specimens have been prepared using this method. It is possible to use these sections for detailed histomorphologic and histomorphometric analysis of bone tissue and of the soft tissue membrane adjacent to the polymethylmethacrylate cement.
Acute toxicity of metal ions in cultures of osteogenic cells derived from bone marrow stromal cells
Authors: Puleo David A. , Huh Winston W. 
Published: May 2005

AbstractThe effects of metal ions released from orthopedic implants on nearby bone cells remain largely unknown. The purpose of this study was to examine the acute toxicity of metal ions on osteogenic cells derived from bone marrow. Bone marrow stromalcells were cultured with metal ions found in commonly used orthopedic implants, that is, Ti‐6Al‐4V, Co‐Cr‐Mo, and 316L stainless steel. Solutions of individual ions and combinations representing the alloy composition were prepared from atomic absorption standards and added to the cultures to give concentrations ranging from 50 ppb to 5o ppm. After a 48‐h period of exposure to ions, the bone marrow cultures were examined for effects of cytotoxicity by measuring total cell number, total cell protein, and mitochondrial activity. Cr6+was grossly cytotoxic; Co2+, Mo6+, Fe3+, and Ni2+were moderately cytotoxic; and Ti4+, Al3+, V5+, and Mn2+were minimally toxic, as determined by the assays used. Ion solutions representing Co‐Cr‐Mo and 316L stainless steel were moderately toxic; solutions representing Ti‐6Al‐4V were toxic at only the highest concentrations used. The observed cytotoxicity was time‐dependent, with irreversible toxic effects being initiated following as short as a 3‐ to 6‐hour exposure. These results show that metal ions associated with Co‐Cr‐Mo and 316L stainless steel are toxic to osteogenic cells at concentrations approximating those measured in the fibrous membrane encapsulating orthopedic implants. © 1995 John Wiley & Sons, Inc.
Materials and design concepts for an intervertebral disc spacer. II. Multidurometer composite design
Authors: Vuono‐Hawkins Monica , Langrana Noshir A. , Parsons John R. , Lee Casey K. , Zimmerman Mark C. 
Published: May 2005

AbstractThe main function of the intervertebral disc is to transmit and attenuate compressive and torsional forces, and stabilize the intervertebral joint. Unfortunately, the disc may be displaced or damaged due to trauma or disease causing the nucleus to herniate and protrude into the vertebral canal or intervertebral foramen. Pressure on the spinal nerve may cause pain or paralysis in the area of its distribution. At present, the surgical procedures used to alleviate this condition include disc excision, and/or spinal fusion. A more desirable situation would involve removing the nucleus pulposus and part or all of the annulus fibrosis and implanting a suitable biofunctional equivalent. Such a prostheis should attenuate stresses and prevent abnormal stress at adjacent intervertebral joints. Maintenance of normal disc height would prevent impingement of the posterior facet joints and facet joint syndrome. In a previous companion paper (J. Applied Biomat. 5:125–132; 1994), the mechanical behavior of disc prostheses manufactured from fiber reinforced, elastomeric thermoset resins were examined. In order to develop devices which were more practical from a manufacturing standpoint and extremely reproducible, the fiber reinforced thermoset resins were replaced by multi‐durometer thermoplastic elastomeric materials. In the present paper, the mechanical properties of thermoplastic multicomponent desings have been investigated. © 1995 John Wiley & Sons, Inc.