bluuebunny/crossref_metadata_2025_split huggingface dataset:
High performance liquid chromatographic determination of levomepromazine in human breast milk and serum using solid phase extraction
Authors: Ohkubo Tadashi , Shimoyama Ritsuko , Sugawara Kazunobu 
Published: May 2005

AbstractA high performance liquid chromatographic (HPLC) method has been developed for the determination of levomepromazine in human breast milk and serum. The levomepromazine was extracted by a rapid and simple extraction method using a Sep‐Pak C18 cartridge. The extracts were separated by HPLC on a C8 bonded reversed phase column and detected by UV absorbance at 254 nm. There was no interference with endogenous substance in human breast milk and serum. A linear relationship was obtained for the levomepromazine over the concentration range of 10–300 ng/mL. The recoveries of levomepromazine added to human breast milk and serum were 92.5–99.1% and 86.9–103.9%, respectively.
Chromatographic determination method for 1‐nitropyrene and its metabolites in biological samples with fluorescence detection after on‐line reduction
Authors: Hayakawa Kazuichi , Terai Noriko , Suzuki Kumiko , Dinning Paul G. , Yamada Masafumi , Miyazaki Motoichi 
Published: May 2005

AbstractA high performance liquid chromatographic (HPLC) method with fluorescence detection after on‐line reduction for the determination of 1‐nitropyrene (NP), 1‐nitrosopyrene (NSP), 1‐aminopyrene (AP) and N‐acetylaminopyrene (AAP) has been developed. The reduction efficiency of NP and NSP on a zinc column was found to be higher than that of an electrochemical reducer. Using a HPLC equipped with a zinc column (4.0 mm i.d. × 10 mm) and an imidazole/HCIO4 (pH 6.8):acetonitrile mobile phase, detection limits (S/N = 3) of 20‐30 fmol for NP, NSP and AP and 350 fmol for AAP were obtained. NP, NSP and AP were determined in the incubation mixture of NP and Salmonella typhimurium, YG1021, by this method. Time course studies showed that a large ratio of NP was metabolized in the pre‐incubation step of the Ames test.
Derivatization with fluorogenic benzofurazan reagents of amino acid enantiomers and their separation on a pirkle column
Authors: Imai Kazuhiro , Fukushima Takeshi 
Published: May 2005

AbstractL‐ and D‐Amino acids (Leu or Phe) were derivatized with fluorogenic reagents, 4‐fluoro‐7‐nitro‐2,1,3‐benzoxadiazole (NBD‐F), 4‐(N,N‐dimethylaminosulfonyl)‐7‐fluoro‐2,1,3‐benzoxadiazole (DBD‐F), 4‐aminosulfonyl‐7‐fluoro‐2,1,3‐benzoxadiazole (ABD‐F) and 5‐(N,N‐dimethylamino)naphthalene‐1‐sulfonylchloride (DNS‐Cl), and separated on a Pirkle type column, Sumichiral OA 2500 (S) ((S)‐1‐naphthylglycyl‐3,5‐dinitrophenylamide silica gel) with a mobile phase of 20 mM ammonium acetate in methanol. The fluorometric detection of the derivatives was made at 530 nm, 590 nm and 530 nm with excitation at 470 nm, 450 nm, 450 nm and 350 nm, respectively. The former three derivatives of the enantiomers were separated well from each other; The as for each NBD‐, DBD‐ and ABD‐derivative of L‐ and D‐Leu were 1.10, 1.11 and 1.10, respectively. However, the DNS derivatives of L‐and D‐Leu were not separated (separation factor, α = 1.0). All NBD‐ and ABD‐derivatives of L‐ and D‐Phe were also well separated (αs were 1.18, 1.17 and 1.16, respectively), while DNS‐L‐ and ‐D‐Phe were barely separated (α = 1.04). These data suggest that the 2,1,3‐benzoxadiazole (benzofurazan) moiety is very effective and preferable to the dimethylaminonaphthalene sulfonyl (DNS) structure for the separation of enantiomers of amino acids derivatized with benzofurazan reagents.No recemization of each enantiomer occurred during the derivatization reaction with NBD‐F, DBD‐F and ABD‐F at pH 8.0 and 60°C for 2 min, at pH 9.3 and 60°C for 30 min and pH 9.3 and 60°C for 60 min, respectively, meaning that all benzofurazan type fluorogenic reagents are useful for sensitive determination of amino acid enantiomers.
Enantioselective bioanalysis of beta‐blocking agents: Focus on atenolol, betaxolol, carvedilol, metoprolol, pindolol, propranolol and sotalol
Authors: Egginger Gabriele , Lindner Wolfgang , Vandenbosch Christel , Massart Desire Luc 
Published: May 2005

AbstractThe recent developments in enantioselective HPLC‐separation techniques are impressive and are driven by industrial and academic interests; thus there is for instance a high demand for developing stereoselective assays for chiral drugs in biological fluids. The beta‐blocking agents, which possess an amino‐ propanol‐ or ‐ethanol side chain with at least one chiral centre, represent one of the most intensively investigated groups of more than 40 drugs introduced world wide. Seven of the most popular beta‐blockers were chosen as representatives: atenolol; betaxolol; carvedilol; metoprolol; pindolol; propranolol; and sotalol, these span the whole range of lipophilicity to hydrophilicity (polarity). Enantioselective HPLC bioassays for these β‐blockers published so far, including techniques based on chiral derivatizing agents (CDAs), chiral stationary phases (CSPs) and chiral mobile phase additives (CMPAs) have been reviewed and documented in the light of general aspects together with pharmacokinetic and pharmacodynamic considerations.
High performance liquid chromatography of tamoxifen and metabolites in plasma and tissues
Authors: Lim C. K. , Chow Loretta C. L. , Yuan Zhi‐Xin , Smith L. L. 
Published: May 2005

AbstractAn isocratic reversed‐phase high performance liquid chromatographic method for the determination of tamoxifen and its metabolites in plasma and tissues is described. Plasma or tissue homogenate was extracted with methanol/dimethyl sulphoxide (4:1 v/v). The supernatant after centrifugation was separated on a BDS‐Hypersil column with methanol/0.5 M ammonium acetate (75:25 v/v) as the mobile phase. The recoveries of tamoxifen added to plasma and liver tissue homogenate by the extraction procedure were 102± 1.6 and 98±2.4% (mean±SD, n = 6), respectively. The solutes were detected at 280 nm with a detection limit of 0.25 μg/mL for tamoxifen.
Relations between blood pressure and plasma norepinephrine concentrations after administration of diltiazem to rats: HPLC‐peroxyoxalate chemiluminescence determination on an individual basis
Authors: Higashidate Sakae , Imai Kazuhiro , Prados Pablo , Adachi‐Akahane Satomi , Nagao Taku 
Published: May 2005

AbstractA calcium antagonist, diltiazem, was infused continuously into Sprague‐Dawley rats through the left femoral vein at four different flow rates. The mean arterial blood pressure and concentrations of plasma norepinephrine (NE) were measured in each single rat (n = 5) and the correlations between them were studied. Blood (150 μL) was collected 13 times during the infusion. Plasma NE was determined by HPLC–ethylenediamine condensation reaction–peroxyoxalate chemiluminescence detection system (HPLC–ED–PO‐CL).In four cases from 5 rats, the blood pressure reduction caused by diltiazem was inversely correlated to logarithm of plasma NE concentration. The relation was expressed as Y = −α logX + m. The coefficients of correlation were −0.9506, −0.9293, −0.9341 and −0.8675, respectively. The correlation for the last rat was worse (r = −0.0799). The good correlation would imply that the sympathetic nervous system released NE to maintain blood pressure up to the normal level, responding to the blood pressure reduction caused by diltiazem.The present experiment proved the feasibility of the determination method of NE utilizing HPLC–ED–PO‐CL detection in applying to the individual rats.
Identification and verification of the anabolic steroid boldenone in equine blood and urine by HPLC/ELIS
Authors: Hagedorn Heinz‐Werner , Schulz Rüdiger , Jaeschke Gerhard 
Published: May 2005

AbstractAn enzyme linked immunosorbent assay (ELISA) was developed to detect the anabolic steroid boldenone in equine blood and urine. The polyclonal antiserum was raised in rabbits, employing boldenone‐17‐hemisuccinate–bovine serum albumin as antigen. Boldenone‐17‐hemisuccinate–horseradish peroxidase served as enzyme conjugate. Sensitivity of the assay was 26.0 ± 3.0 pg/well. Among the endogenous steroids tested only progesterone and testosterone exhibited moderate cross‐reactivities, 3.4 and 2.5%, respectively. These crossreactivities are of no importance for the boldenone assay. For the reduction of background levels, srceening for boldenone of equine serum was performed after extraction. Urine samples were determined directly after dilution, omitting hydrolysis of boldenone conjugates. Positive screening results were confirmed by means of two independent HPLC systems combined with off‐line detection, employing the boldenone ELISA. Methandienone served as internal standard to ascertain retention factors. In horses treated with boldenone‐17‐undecylenate the presence of boldenone in serum was confirmed up to 28 days and in unhydrolysed urine up to 56 dayspost applicationem.
Quantitative relationships between the structure of β‐adrenolytic and antihistamine drugs and their retention on an α1‐acid glycoprotein HPLC column
Authors: Nasal Antoni , Radwańska Aleksandra , Ośmiałowski Krzysztof , Buciński Adam , Kaliszan Roman , Barker Geoffrey E. , Sun Peng , Hartwick Richard A. 
Published: May 2005

AbstractChromatographic retention parameters of a series of 7 β‐adrenolytics and of 12 antihistamine drugs were determined employing an α1‐acid glycoprotein (AGP) high‐performance liquid chromatographic (HPLC) column. For the group of antihistamines capillary electrophoretic (CE) retention was additionally measured in the presence of either AGP or human serum albumin (HSA). Two series of solutes hydrophobicity parameters were obtained by reversed‐phase HPLC on an immobilized artificial membrane (IAM) column. The solutes studied were subjected to molecular modelling and the structural descriptors obtained were applied in studies of quantitative structure‐retention (protein binding) relationships (QSRR). It was found that retention on AGP correlates well with the literature on physiological protein binding data. This retention was demonstrated to depend on hydrophobicity: to a lesser extent in the case of β‐adrenolytics and strongly in the case of antihistamines. Hydrophobicity, along with molecular width and electron excess charge on aliphatic nitrogen was demonstrated to describe retention of antihistamines on AGP. The AGP column is recommended as a convenient reactor for studies of drug–protein interactions. Preliminary CE data do not correlate with the HPLC data.
Proteinergic profiles in cerebrospinal fluid from alcoholic subjects
Authors: Silberring Jerzy , Brostedt Peter , Neiman Jack , Hellman Ulf , Liljequist Sture , Terenius Lars 
Published: May 2005

AbstractMinute amounts of cerebrospinal fluid samples from alcoholics were subjected to separation by HPLC‐molecular sieving, combined with multispectral UV analysis of the acquired data. A significant difference in the protein/polypeptide pattern within the molecular weight range of 7–10 kDa has been observed between samples, taken directly after detoxification and 2 weeks later. Spectral analysis of the results suggests that the components are of peptidergic nature. On the other hand, albumin content did not differ significantly, suggesting that the blood–brain barrier was not affected. An enzyme marker, dynorphin converting enzyme, remained unchanged in both groups.
Enantiospecific determination of ibuprofen in rat plasma using chiral fluorescence derivatization reagent, (−)‐2‐[4‐(1‐aminoethyl)‐phenyl]‐6‐methoxybenzoxazole
Authors: Kondo Junichi , Suzuki Nobuyuki , Naganuma Hideo , Imaoka Toshi , Kawasaki Takao , Nakanishi Akio , Kawahara Yukinori 
Published: May 2005

AbstractA highly sensitive and reversed‐phase high‐performance liquid chromatographic method for the determination of the enantiomeric composition of ibuprofen in rat plasma is described. The method is based on the resolution of the diastereomeric amides formed on reaction of the ibuprofen enantiomers with (−)‐2‐[4‐(1‐aminoethyl)phenyl]‐6‐methoxybenzoxazole ((−)‐APMB) in the presence of 2,2′‐dipyridyl disulphide (DPDS) and triphenylphosphine (TPP) in dichloromethane. The reaction mixture was allowed to stand at room temperature for 5 min, and the reaction was completed by evaporation with a stream of nitrogen at 40°C. The minimum quantifiable concentrations were 0.2 μg/mL and 0.4 μg/mL for S‐ibuprofen and R‐ibuprofen, respectively, in a 10 μL injection volume. The method was applied to the determination of enantiomeric ibuprofen in plasma after oral administration to rats.
Gas chromatography–mass spectrometry determination of etodolac in human plasma following single epicutaneous administration
Authors: Giachetti Claudio , Assandri Alessandro , Zanolo Giovanni , Brembilla Emilio 
Published: May 2005

AbstractA highly sensitive gas chromatographic–mass spectrometric method for the determination of etodolic acid, as methyl ester, in plasma was developed. The feasibility and specificity of the method was ascertained monitoring the concentration levels in plasma samples collected from 12 male healthy volunteers given epicutaneously 5 g of 10% etodolac gel formulation.
TLC—A rapid method for liposome characterization
Authors: Brailoiu Eugen , Saila Liliana , Huhurez Gabi , Costuleanu Marcel , Filipeanu Catalin M. , Slatineanu Sebastian , Cotrutz Carmen , Branisteanu Dimitrie D. 
Published: May 2005

AbstractOne of the most important problems for the use of liposomes as a drug delivery system is the modification of the vesicle induced by the liquid medium in which they are introduced (blood plasma for in vivo studies and the saline buffer solution for in vitro studies).Using thin‐layer chromatography (TLC) we compared the behaviour of phosphatidylcholine (used for liposomes preparation) to that of the following unfilled liposomes: multilamellar liposomes (MLV); small unilamellar vesicles (SUV); and reverse phase evaporation vesicles (REV), before and after storage for 15 min in Krebs‐Henseleit solution (37°C, pH 7.4, aereated continuously with 95% O2 + 5% CO2). All variants contained the same amount of phosphatidylcholine.Thin‐layer chromatography was performed on silica gel 60 as adsorbant. Two types of solvents were tested: one based on chloroform/alcohol (n‐butanol or n‐propanol or methanol)/water mixture (in different ratios) and another based on alcohol/alcohol/water mixture (n‐butanol/n‐propanol/water in 4/3/3 volume ratio). In all variants of chloroform containing solvents no differences were found between phosphatidylcholine and all types of liposomes.When using as solvent n‐butanol/n‐propanol/water significant differences were found between all types of liposomes before and after storage in Krebs‐Henseleit solution. Their presence, after TLC treatment, was shown in electron microscopy studies.
Separation of vitamin B complex and folic acid using TLC plates impregnated with some transition metal ions
Authors: Bhushan Ravi , Parshad Vineeta 
Published: May 2005

AbstractThe separation of Vitamin B complex and folic acid was achieved on silica gel layers impregnated with Mn++, Fe++, Co++, Ni++, Cu++, Cd++, Zn++ or Mg++ (0.1%, 0.2%, 0.3%, 0.4% of each ion). Three new solvent systems n‐propanol: n‐butanol: water: ammonia (7:5:1:2, by vol), n‐propanol: n‐butanol: water: ammonia (7:5:1:1.5, by vol), n‐propanol: n‐butanol: water: ammonia (7:5:0.75:2, by vol) were developed. The spots of vitamins were located by exposing the chromatoplate to iodine vapours.
A non‐radioactive iothalamate and p‐aminohippuric acid high‐performance liquid chromatographic method for simultaneously measuring glomerular filtration rate and renal blood flow in the rat
Authors: Bell Rosonald R. , Bombardt Paul A. , DuCharme Donald W. , Kolaja Gerald J. , Packwood William H. , Bothwell Brian E. , Satoh Paul S. 
Published: May 2005

AbstractA high‐performance liquid chromatographic (HPLC) assay method has been developed for the quantitative determination of iothalamate and p‐aminohippuric acid (PAH) concentrations in serum and urine samples in the male rat. Glomerular filtration rate (GFR) was measured as clearance of iothalamate, while effective renal blood flow (ERBF) was measured as clearance of PAH. The method is simple, rapid and sensitive and detects iothalamate and PAH in rat serum and urine following administration of bolus doses and continuous infusions of iothalamate and PAH. Samples of serum and urine were deproteinized with two volumes of acetonitrile containing the internal standard, and an aliquot chromatographed on a C18 reversed‐phase column. The mobile phase was comprised of 0.1 M sodium phosphate with 1.2 mM tetrabutylammonium phosphate: methanol, 85:15 (v/v), at a flow rate of 1.0 mL/min. The analytical column eluate was monitored with a UV detector at 254 nm with quantitation achieved using peak‐height ratios. The precision of the method was 6.6 and 3.6% for iothalamate in serum and urine, and 5.6 and 4.9% for PAH in serum and urine, respectively. The lower limit of quantitation was 0.63 μg/mL for iothalamate and 1.25 μg/mL for PAH in serum, and 3.1 μg/mL for iothalamate and 1.5 μg/mL for PAH in urine. Recovery of iothalamate from serum and urine was 99.9 and 93.5%, respectively. Recovery of PAH from serum and urine was 99.8 and 92.6%, respectively.The present study demonstrated that non‐radioactive iothalamate and PAH can be measured simultaneously using a HPLC assay to measure GFR and ERBF in the male rat.
Determination of fluvoxamine concentration in plasma by reversed‐phase liquid chromatography
Authors: Wong Steven H. Y. , Kranzler Henry R. , Dellafera Sandra , Fernandes Rosinda 
Published: May 2005

AbstractFluvoxamine, a serotonin re‐uptake inhibitor, was quantified in plasma by modifying a previously published procedure for monitoring plasma concentrations of tricyclic antidepressants. Alkalinized plasma samples were extracted with n‐hexane/isoamyl alcohol, followed by back‐extraction with diluted phosphoric acid, The extracts were analysed by reversed‐phase liquid chromatography using a C‐18 column, with phosphate/acetonitrile as the mobile phase. The assay was linear from 10 to 800 μg/L. Precision studies showed within‐run and day‐to‐day coefficients of variation to be 4.5 and 6.8%, respectively. Desipramine interfered with the detection of fluvoxamine. The assay was used to measure a total of 8 plasma samples from 4 alcohol‐dependent patients medicated with fluvoxamine as an adjunct to relapse prevention psychotherapy. In these patients, the plasma concentrations ranged from 54 to 241 μg/L. Dosage of fluvoxamine, duration of treatment, interval between last dosage and blood collection were associated with effects on plasma concentrations that were consistent with the pharmacokinetic profile of fluvoxamine.
Mannitol prevents methionine sulphoxidation mediated electrophoretic heterogeneity of apolipoprotein A‐I
Authors: Nofer Jerzy‐Roch , von Eckardstein Arnold , Assmann Gerd 
Published: May 2005

AbstractHybrid isoelectic focusing of apolipoprotein A‐I in polyacrylanide gels with immobilized pH‐gradients under non‐denaturing conditions resulted in the occurrence of additional bands which could prevent the specific and sensitive detection of genetic variants. Hybrid isoelectric focusing of tow chromatographically distinguishable apolipoprotien A‐I isoforms that differ by sulphoxidaton of methionine residues, apo A‐I(Met) and apo A‐I(MetSO), revealed that the additional bands were caused by this post‐translational modification. Several antioxidative additives and conditions were compared for their ability to prevent methionine sulphoxidation in apoliporotein A‐I In the presence of 200 g/L mannitol in the gel, apolipoprotein A/I focused as a single band. Since methionine sulphoxidation in proteins is a general phenomenon either taking place in vivo or in vitro by isoelectric focusing, we conclude that isoelectric focusing in the presence of mannitol will improve the quality of resolution of many proteins in gels with immobilized pH‐gradients.
Determination of oxeladin in human plasma by gas chromatography—mass spectrometry
Authors: Lartigue‐Mattei C. , Galmier M. J. , Chabard J. L. , Beyssac E. , Aiache J. M. 
Published: May 2005

AbstractA capillary gas chromatographic method with mass‐selective detection was developed for the determination of oxeladin in human plasma. Plasma samples (1 mL) were alkalinized and extracted using 5 mL of hexane: isoamyl alcohol (99:1). The method was demonstrated to be sensitive (limit of quantitation at 1 ng/mL), linear between 1 and 150 mg/mL, accurate and precise enough (mean error and mean coefficient of variation at the limit of quantitation were 2.3 and 13.3%, respectively) to support pharmacokinetic evaluation of the drug at doses down to 30 mg.
Purification of murine immunoglobulin M from spent tissue culture supernatant by one‐step gel filtration chromatography procedure
Authors: Novales‐Li Philipp 
Published: May 2005

AbstractOptimal purification of immunoglobulin M (IgM) grown as spent tissue culture supernatant can be achieved by a straightforward size‐exclusion chromatography procedure. Preparative isolation of IgM was achieved by precipitation with saturated ammonium sulphate to achieve a 45% solution. IgM was then purified by gel filtration chromatography with a solution of 100 mM Tris+150 mM NaCl at pH 8. Denaturing electrophoresis and Western immunoblotting revealed two prominent bands at 80 and 25 kDa, indicative of the heavy and light chains of IgM respectively. The specific immunoreactivity of this IgM was assessed by a modified enzyme antigen capture assay. In contrast to affinity and ion‐exchange chromatographies, gel filtration allows retention of IgM immunoreactivity.
Sensitive determination of salmon calcitonin, by means of pre‐column derivatization, HPLC and fluorometric determination
Authors: Fukuda Terumi , Ishikawa Kazuyuki , Imai Kazuhiro 
Published: May 2005

AbstractA high sensitive analytical method for salmon calcitonin (sCT) was established by means of derivatization with a fluorescence labelling agent, DBD‐F, followed by HPLC separation and fluorescence detection at 558 nm with excitation at 430 nm.Under optimized conditions (DBD‐F, 0.1 M borate buffer (pH 8.5): acetonitrile (70:30, v/v)), three molecules of DBD‐F reacted with one sCT molecule in the presence of 1 mM sodium dodecyl sulphate (SDS) at 50 oC for 3 h. The detection limit for the sCT derivative was 20 fmol. A linear relationship was obtained between the amount of sCT on column and the peak heights in the range of 35–8000 fmol.
High‐performance liquid chromatography and fluorometric detection of arachidonylethanolamide (anandamide) and its analogues, derivatized with 4‐(N‐chloroformylmethyl‐N‐methyl) amino‐7‐N, N‐dimethylaminosulphonyl‐2,1,3‐benzoxadiazole (DBD‐COCl)
Authors: Koga Daisuke , Santa Tomofumi , Hagiwara Kenichi , Imai Kazuhiro , Takizawa Hiromasa , Nagano Tetsuo , Hirobe Masaaki , Ogawa Masako , Sato Taku , Inoue Keizo , Kudo Ichiro 
Published: May 2005

AbstractThe endogeneous ligand for the cannabinoid receptor, arachidonylethanolamide (anandamide) and its analogues, oleinylethanolamide, palmitylethanolamide and eicosapentaenoylethanolamide, were derivatized with a fluorogenic reagent, 4‐(N‐chloroformylmethyl‐N‐methyl)amino‐7‐N, N‐dimethylaminosulphony 1‐2,1,3‐benzoxadiazole (DBDCOCl). They were separated on a reversed phse HPLC with a mobile phase of acetonitrile: water. The fluorometric detection of the derivatives was made at 560 nm with excitation at 450 nm and the detection limits for anandamide was 20 fmol on column. The structures of DBDCO‐ethanolamides were confirmed by liquid chromatography‐atmospheric pressure chemical ionization—mass spectrometry (LCAPCIMS).