bluuebunny/crossref_metadata_2025_split huggingface dataset:
Joint application of micro‐Raman and surface‐enhanced Raman spectroscopy to the interaction study of the antitumoral anthraquinone drugs danthron and quinizarin with albumins
Authors: Fabriciova G. , Sanchez‐Cortes S. , Garcia‐Ramos J. V. , Miskovsky P. 
Published: May 2004

AbstractWe report on the joint application of surface‐enhanced Raman scattering (SERS) and micro‐Raman techniques to the study of danthron (DT) and quinizarin (QZ) and their complexes with human and bovine albumins. We propose a novel method based on the combination of SERS and micro‐Raman spectroscopy by using immobilized Ag nanoparticles, which we have named micro‐SERS, to improve the sensitivity of the SERS technique and that could be applied in recognition processes of drugs with large biomolecules. The micro‐SERS technique demonstrated clear advantages over direct measurements in air: reproducibility, rapidity and high sensitivity due to a large coverage of the metal surface and good organization of the adsorbate on the surface. Furthermore, the chemical damage of the analyte induced by laser irradiation is substantially reduced. By means of this method, we were able to deduce important information concerning the binding properties of DT and QZ when interacting with human and bovine albumins. For instance, the interaction mechanism can be drastically modified when fatty acids are present in albumins, there are large differences between human and bovine albumins in the binding of the studied drugs related to changes in the amino‐acid sequence of the binding pockets of these proteins and the interaction mechanism of the analysed drugs can be different depending on their structure. Copyright © 2004 John Wiley & Sons, Ltd.
Identification and characterization of pharmaceuticals using Raman and surface‐enhanced Raman scattering
Authors: Cîntǎ Pînzaru S. , Pavel I. , Leopold N. , Kiefer W. 
Published: May 2004

AbstractMany recent papers reflect ongoing research and development concerning pharmaceutical applications of Raman techniques. This short review highlights different Raman techniques (dispersive, Fourier transform, resonance Raman, SERS, SERRS, FT‐SERS) employed in pharmaceutical investigations. Several Raman applications such as fundamental structural investigations, quantitative analysis, drug–excipient interaction, formulation, limit of detection, pH‐dependent pharmaceutical species, adsorption geometry at a given surface and functional groups involved in adsorption for several widely used pharmaceutical compounds are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Near‐infrared Fourier transform surface‐enhanced Raman scattering spectroscopy of 1,4‐benzodiazepine drugs employing gold films over nanospheres
Authors: Trachta Gerd , Schwarze Bernd , Brehm Georg , Schneider Siegfried , Hennemann Matthias , Clark Timothy 
Published: May 2004

AbstractSERS spectra of eight benzodiazepine drugs were recorded with an FT‐NIR Raman spectrometer employing AuFONs (gold films over nanospheres) as SERS‐active substrates. A tentative assignment of the vibrational bands was made by comparison with the Raman spectra of crystalline reference samples and the results of density functional theory (DFT) calculations. It is concluded that the bands observed in the SERS spectra are almost exclusively due to vibrations located on rings a and b of the benzodiazepine moiety. The latter should be adsorbed with the molecular plane essentially orthogonal to the metal surface. However, different adsorption geometries are postulated for derivatives containing NH or NCH3 groups. It is demonstrated that a few hundred nanograms of analyte per well are sufficient to record spectra that allow identification and discrimination of the drugs. Such amounts can be collected at the output of an HPLC instrument employed for separating these drugs from blood serum. Copyright © 2004 John Wiley & Sons, Ltd.
Polyethylene oxides: protection potential against polymorphic transitions of drugs?
Authors: Schmidt Andrea G. , Wartewig Siegfried , Picker Katharina M. 
Published: May 2004

AbstractPolyethylene oxides (PEOs) were analysed in mixtures with polymorphic drugs to test their potential in order to prevent polymorphic or pseudopolymorphic transitions, which are induced by the tableting process. Five PEOs with different molecular weights were tested in comparison with the well‐known tableting excipients microcrystalline cellulose (MCC), hydroxypropylmethylcellulose (HPMC) and dicalcium phosphate dihydrate (DCPD). Amorphous indomethacin was chosen as the model drug. Its recrystallization behaviour is well known and can be mechanically stimulated. Theophylline monohydrate was also used; its dehydration is induced by tableting. Pure materials and mixtures containing 20% (w/w) of drug were compressed at different maximum relative densities. The tablets were broken in order to determine the degree of transformation inside by FT‐Raman spectroscopy. For quantitative interpretation, the intensities of representative Raman bands were used. Differential scanning calorimetry (DSC) was applied additionally. In tablets and mixtures of amorphous indomethacin and PEOs, recrystallization was dramatically lowered in comparison with the other excipients. The molecular weights of the various PEOs seem to have no influence. The Raman spectra indicate chemical interactions as the reason. Thus, PEO can stabilize amorphous indomethacin. DSC investigations verified these results. For theophylline monohydrate, no interactions could be detected and DCPD showed the best protection properties. Hence the results concerning indomethacin cannot be generalized, but blending with PEO could be a simple method to stabilize amorphous indomethacin. Copyright © 2004 John Wiley & Sons, Ltd.
Development of sampling methods for Raman analysis of solid dosage forms of therapeutic and illicit drugs
Authors: Bell Steven E. J. , Beattie J. Renwick , McGarvey John J. , Peters K. Laota , Sirimuthu N. M. S. , Speers S. James 
Published: May 2004

AbstractThe results of a study aimed at determining the most important experimental parameters for automated, quantitative analysis of solid dosage form pharmaceuticals (seized and model ‘ecstasy’ tablets) are reported. Data obtained with a macro‐Raman spectrometer were complemented by micro‐Raman measurements, which gave information on particle size and provided excellent data for developing statistical models of the sampling errors associated with collecting data as a series of grid points on the tablets' surface. Spectra recorded at single points on the surface of seized MDMA–caffeine–lactose tablets with a Raman microscope (λex = 785 nm, 3 µm diameter spot) were typically dominated by one or other of the three components, consistent with Raman mapping data which showed the drug and caffeine microcrystals were ca 40 µm in diameter. Spectra collected with a microscope from eight points on a 200 µm grid were combined and in the resultant spectra the average value of the Raman band intensity ratio used to quantify the MDMA: caffeine ratio, µr, was 1.19 with an unacceptably high standard deviation, σr, of 1.20. In contrast, with a conventional macro‐Raman system (150 µm spot diameter), combined eight grid point data gave µr = 1.47 with σr = 0.16. A simple statistical model which could be used to predict σr under the various conditions used was developed. The model showed that the decrease in σr on moving to a 150 µm spot was too large to be due entirely to the increased spot diameter but was consistent with the increased sampling volume that arose from a combination of the larger spot size and depth of focus in the macroscopic system. With the macro‐Raman system, combining 64 grid points (0.5 mm spacing and 1–2 s accumulation per point) to give a single averaged spectrum for a tablet was found to be a practical balance between minimizing sampling errors and keeping overhead times at an acceptable level. The effectiveness of this sampling strategy was also tested by quantitative analysis of a set of model ecstasy tablets prepared from MDEA–sorbitol (0–30% by mass MDEA). A simple univariate calibration model of averaged 64 point data had R2 = 0.998 and an r.m.s. standard error of prediction of 1.1% whereas data obtained by sampling just four points on the same tablet showed deviations from the calibration of up to 5%. Copyright © 2004 John Wiley & Sons, Ltd.
Applications of Raman spectroscopy to pharmacy
Authors: Fini Giancarlo 
Published: May 2004

AbstractThis paper gives a summary of this special issue on ‘Pharmaceutical Applications of Raman Spectroscopy’. It summarizes the papers collected and introduces the possible applications of classical Raman spectroscopy (macro and micro) and surface‐enhanced Raman spectroscopy to the identification of pharmacologically active substances, their qualitative and quantitative analysis, characterization of crystalline forms and structure determination. Copyright © 2004 John Wiley & Sons, Ltd.
Rural tourism in Australia — has the gaze altered? Tracking rural images through film and tourism promotion
Authors: Beeton Sue 
Published: May 2004

AbstractAustralians' image of themselves and how others view them is embedded in the images presented by contemporary popular media, both domestic and international. Many of these images are rural; however, they are not based on a Romantic rural idyll but, rather, stem from notions of the Australian ‘bush’. The meaning behind these images not only reflects the attitudes and political environment of the day, but also can influence potential tourists' desire to visit the country. By looking at three film versions (spanning almost a century) of the popular Australian bushranging legend, Ned Kelly, and their relationship with tourism images, we can start to consider this relationship. While the Kelly legend is influential in terms of Australian self‐image, the images presented in the movies do not correlate with the tourism images of the time. Such dissonance creates confusion in visitors' perceptions and represents lost promotional opportunities possibly even having a negative effect on rural tourism. Copyright © 2004 John Wiley & Sons, Ltd.
Kinetic investigation of gas‐phase reactions between the OH‐radical and o‐, m‐, p‐ethyltoluene and n‐nonane in air
Authors: Colomb A. , Jacob V. , Kaluzny P. , Baussand P. 
Published: May 2004

AbstractWe have carried out relative rate experiments (T = 294 ± 2 K, atmospheric pressure) to investigate the OH‐oxidation of o‐, m‐, and p‐ethyltoluene and n‐nonane (k1, k2, k3, and k4 respectively). The experiments were performed in a 2‐m3 smog chamber with Teflon coated walls. The rate constants obtained are (in cm3 molecule−1 s−1 with two sigma uncertainties): k1 = (1.36 ± 0.07) × 10−11; k2 = (2.12 ± 0.26) × 10−11; k3 = (1.47 ± 0.04) × 10−11, and k4 = (0.95 ± 0.02) × 10−11. The measured rate constants are in accordance with previously published data, so that a coherent group of values for the compounds studied can be established. Atmospheric implications, ozone, and particle production are discussed. In addition, we have determined the amount of o‐, m‐, and p‐ethyltoluenes in different types of gasoline. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 367–378 2004
Rate coefficients for the gas‐phase reactions of OH radicals with methylbutenols at 298 K
Authors: Imamura Takashi , Iida Yumi , Obi Kinichi , Nagatani Ikue , Nakagawa Kazumichi , Patroescu‐Klotz Iulia , Hatakeyama Shiro 
Published: May 2004

AbstractThe relative‐rate method has been used to determine the rate coefficients for the reactions of OH radicals with three C5 biogenic alcohols, 2‐methyl‐3‐buten‐2‐ol (k1), 3‐methyl‐3‐buten‐1‐ol (k2), and 3‐methyl‐2‐buten‐1‐ol (k3), in the gas phase. OH radicals were produced by the photolysis of CH3ONO in the presence of NO. Di‐n‐butyl ether and propene were used as the reference compounds. The absolute rate coefficients obtained with the two reference compounds agreed well with each other. The O3 and O‐atom reactions with the target alcohols were confirmed to have a negligible contribution to their total losses by using two kinds of light sources with different relative rates of CH3ONO and NO2 photolysis. The absolute rate coefficients were obtained as the weighted mean values for the two reference compound systems and were k1 = (6.6 ± 0.5) × 10−11, k2 = (9.7 ± 0.7) × 10−11, and k3 = (1.5 ± 0.1) × 10−10 cm3 molecule−1 s−1 at 298 ± 2 K and 760 torr of air. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 379–385 2004
Thermal decomposition of tert‐butyl peroxide in a gas chromatographic reactor: A comparison of kinetic approaches
Authors: Skrdla Peter J. 
Published: May 2004

AbstractThe thermal decomposition of tert‐butyl peroxide is investigated utilizing both the column and the injection port of a commercial gas chromatograph (GC) as chemical reactors. Using the injector liner as the reactor, the chromatographic peak areas of the reactant, measured at various injector temperatures, are used in the determination of the activation energy of the decomposition (Ea). With the column serving as the reactor, both the reactant peak areas and the product peak shapes are similarly utilized for this purpose. Values of Ea obtained using different mathematical treatments for each of the three approaches are found to range from 115 to 164 kJ/mol. Of these methods, the column reactor approach utilizing peak area measurements (referred to as PACR, for “peak area, column reactor”) is found to be far superior in terms of its speed, robustness, and its accuracy in determining Ea. The PACR method's effectiveness can be largely attributed to the mathematical treatment that is described in the approach. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 386–393, 2004
Effect of binary aqueous‐organic solvents on the reaction of phenacyl bromide with nitrobenzoic acid(s) in the presence of triethylamine
Authors: Nallu M. , Subramanian M. , Vembu N. , Akber Hussain A. 
Published: May 2004

AbstractSecond‐order rate constants (k2) of the reaction between phenacyl bromide and equimolar mixture of nitrobenzoic acid(s)–triethylamine have been determined in dimethylformamide (DMF)/acetonitrile (ACN)/acetone and aqueous mixtures of these solvents by conductometric method at 30°C. The rates of nitrobenzoic acids are found to be in the order: 4‐NO2 > 3‐NO2 > 3,5‐(NO2)2. Changes in the rate just by the addition of water (1% (v/v)) into organic component is rationalized. Decrease in the values of k2 on increasing water content in organic solvent is explained on the basis of preferential solvation phenomenon. Single and dual regression analysis using the various solvent parameters of aqueous mixtures (ET(30), Z, π*, β, α, and Y) resulted in π* and α as the best parameters to explain solvation of nitrobenzoates. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 401–409, 2004
Study of the base‐catalyzed nitrito–nitro isomerization reaction ([(NH3)5Co‐ONO]2+ → [(NH3)5Co‐NO2]2+) in mixed solvents
Authors: Jiménez R. , Villar M. , Cueto M. , Grueso E. , Illanes J. , Cobrian J. I. , Cantón F. , Villa I. , Sánchez J. M. , Maza S. , Muñoz J. M. , Muñoz C. , Prado‐Gotor R. 
Published: May 2004

AbstractThe base‐catalyzed linkage isomerization of [Co(NH3)5‐ONO]2+ to the nitro [(NH3)5Co‐NO2]2+ form is studied in various isodielectric water–cosolvent mixtures (methanol, ethanol, tert‐butyl alcohol, and 2‐propanol) at 298 K. In all cases, except for methanol–water mixtures, the rate constants increase with the proportion of cosolvent. Medium effects have been rationalized by using a multiparameter regression of solvent parameters which rationalizes the results obtained, including water–methanol mixtures. The experimental data, k2, in fact, are well correlated through the following equation:

equation image

where A, B, and Gexc are the acidity parameter, the basicity parameter, and the excess Gibbs free energy of the mixture, respectively. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 410–415, 2004
Kinetics and mechanism of oxidation of a ternary complex involving dipicolinatochromium(III) and DL‐aspartic acid by N‐bromosuccinimide
Authors: Ewais Hassan A. , Ahmed Ahmed E. , Abdel‐Khalek Ahmed A. 
Published: May 2004

AbstractThe kinetics of oxidation of [CrIII(Dpc)(Asp)(H2O)2] (Dpc = dipicolinic acid and Asp = DL‐aspartic acid) by N‐bromosuccinimide (NBS) in aqueous solution have been found to obey the equation:

equation image

where k2 is the rate constant for the electron transfer process, K1 is the equilibrium constant for deprotonation of [CrIII(Dpc)(Asp)(H2O)2], K2 and K3 are the pre‐equilibrium formation constants of precursor complexes [CrIII(Dpc)(Asp)(H2O)(NBS)] and [CrIII(Dpc)(Asp)(H2O)(OH)(NBS)]−. Values of k2 = 4.85 × 10−2 s−1, K1 = 1.85 × 10−7 mol dm−3, and K2 = 78.2 mol−1 dm3 have been obtained at 30°C and I = 0.1 mol dm−3. The experimental rate law is consistent with a mechanism in which the deprotonated [CrIII(Dpc)(Asp)(H2O)(OH)]− is considered to be the most reactive species compared to its conjugate acid. It is assumed that electron transfer takes place via an inner‐sphere mechanism. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 394–400, 2004
Binding of the Bioactive Component Daphnetin to Human Serum Albumin Demonstrated Using Tryptophan Fluorescence Quenching
Authors: Liu Jiaqin , Tian Jianniao , Li Ying , Yao Xiaojun , Hu Zhide , Chen Xingguo 
Published: May 2004

AbstractSummary: Daphnetin (7,8‐dihydroxycoumarin), one of the major bioactive components isolated from Daphne koreane Nakai, has been used in traditional Chinese medicine for the treatment of coagulation disorders. It is also a chelator, an antioxidant and a protein kinase inhibitor. In this paper, a combination of intrinsic fluorescence, Fourier transform infrared (FT‐IR) spectroscopy and circular dichroic (CD) spectroscopy has been used to characterize the binding between daphnetin and human serum albumin (HSA) under physiological conditions with drug concentrations of 6.7 × 10−6 − 2.3 × 10−5 mol · L−1, and a HSA concentration of 1.5 × 10−6 mol · L−1. Changes in the CD spectra and FT‐IR spectra were observed upon ligand binding, and the degree of tryptophan fluorescence quenching did change significantly in the complexes. These data have proved the change in protein secondary structure accompanying ligand binding. The change in tryptophan fluorescence intensity was used to determine the binding constants. The thermodynamic parameters, the enthalpy change (ΔH) and the entropy change (ΔS) were calculated to be −12.45 kJ · mol−1and 52.48 J · mol−1 · K‐1 according to the van't Hoff equation, which indicated that hydrophobic and electrostatic interactions played the main role in the binding of daphnetin to HSA, in accordance with the results of calculations performed on a Silicon Graphics Ocatane2 workstation. In addition, the binding distance between daphnetin and HSA was obtained (4.02 nm) based on the Förster energy transfer theory.The binding mode between daphnetin and HSA.imageThe binding mode between daphnetin and HSA.
Butyl Acrylate/Vinyl Acetate Miniemulsion Polymerization: A Study on Compartmentalization
Authors: Jovanovic Renata , Dubé Marc A. 
Published: May 2004

AbstractSummary: A series of butyl acrylate/vinyl acetate miniemulsions were investigated. Two procedures were used to prepare the miniemulsions: one in which the monomers were mixed together, sonicated, and polymerized, and the other, in which the individual monomers were sonicated prior to mixing and then polymerized. Kinetic and final properties of the obtained polymers were compared. The two procedures offer interesting insights into monomer compartmentalization in miniemulsions. In most cases, there were no differences in monomer conversion, copolymer composition, particle size or average molecular weights between the two procedures. ATR‐FTIR spectroscopy was used to assess possible monomer transfer. The spectra obtained from each polymerization procedure were compared and no evidence of compartmentalization was found. Both procedures yielded similar spectra indicating that monomer transfer between particles occurred. In addition, adhesive properties of the obtained latexes were investigated. Due to the fact that relatively large amounts of CTA were used, adhesive performance was poor.Comparison of the spectra of miniemulsion polymerizations obtained by two different procedures (BA/VAc 85/15 wt/wt).imageComparison of the spectra of miniemulsion polymerizations obtained by two different procedures (BA/VAc 85/15 wt/wt).
Determination of the Kinetic Constants of the Telomerization of 10‐Undecenol with Alkyl Hydrogenphosphonate
Authors: Senhaji Omar , Robin Jean Jacques , Achoubi Mohammed , Boutevin Bernard 
Published: May 2004

AbstractSummary: The telomerization of 10‐undecenol with alkyl hydrogenphosphonate was studied in order to synthesize telomers of different molecular weights. The study showed that telomers from 10‐undecenol could be obtained despite the fact that the double bond has a low reactivity. The kinetic constant Kp2/KTe was determined to be 7 × 10−4 l · mol−1 · s−1 at 135 °C and the transfer constant CT was 0.057. These values are normal for a low activity telogen such as hydrogenphosphonate and for slightly reactive monomers like 10‐undecenol.SEC chromatogram of telomers obtained in the reaction of 10‐undecenol addition.imageSEC chromatogram of telomers obtained in the reaction of 10‐undecenol addition.
Primary Amine‐Initiated Polymerizations of Alanine‐NCA and Sarcosine‐NCA
Authors: Kricheldorf Hans R. , von Lossow Colin , Schwarz Gert 
Published: May 2004

AbstractSummary: Sarcosine‐N‐carboxyanhydride (Sar‐NCA), L‐alanine‐NCA and D,L‐alanine‐NCA were polymerized with benzylamine as initiator in three different solvents: dichloromethane (CH2Cl2), 1,4‐dioxane and dimethylformamide (DMF). The isolated polyaminoacids were characterized by 1H NMR spectroscopy and MALDI‐TOF mass spectrometry. High conversions and degrees of polymerization $\overline {DP}$s close to the monomer‐initiator (M/I) ratios were found for all polypeptides. For polysarcosine which was soluble under the given reaction conditions a narrow monomodal frequency distribution was found. In contrast, a broad frequency distribution was observed, when L‐alanine NCA was polymerized in dioxane and DMF. These results were attributed to a partial precipitation of oligopeptides in the β‐sheet structure, which reduces the reactivity of endgroups for steric reasons. The polymerizations of D,L‐alanine‐NCA showed features in between the extremes of Sar‐NCA and L‐Ala‐NCA.Schematic illustration of the secondary structures formed in a primary amine initiated polymerization of L‐Ala‐NCA.imageSchematic illustration of the secondary structures formed in a primary amine initiated polymerization of L‐Ala‐NCA.