Analysis of glucose and lactate in dialysate from hypothalamus of rats after exhausting swimming using microdialysisWang, L.; Dong, Y.; Yu, X.; Shangguan, D. H.; Zhao, R.; Han, H. W.; Liu, G. Q.
doi: 10.1002/bmc.177pmid: 12378551
A microbore flow injection analysis–immobilized enzyme reactor–electrochemical detection (FIA‐IMER‐ECD) system for glucose and lactate detection was built up. The assays were precise, sensitive and practicable for determination of glucose and lactate levels in hypothalamic dialysate. The method had been used to detect the dynamic changes of glucose and lactate levels during rat exhausting swimming and recovery. The data showed that after exhausting swimming, the concentration of glucose in hypothalamic dialysate that reflected the concentration in the hypothalamic extracellular fluid decreased. The level fell to its nadir at day 1 after the exercise and then went back to the basal level at day 3 after the swimming. However, lactate levels increased to a maximum at day 3 and went back to the basal level at day 5 after the swimming. Copyright © 2002 John Wiley & Sons, Ltd.
Simultaneous detection of monohydroxybenzo( a )pyrene positional isomers by reversed‐phase liquid chromatography coupled to electrospray ionization mass spectrometrySasaki, Hideki; Yonekubo, Jun; Kanai, Michiko; Toriba, Akira; Kizu, Ryoichi; Hayakawa, Kazuichi
doi: 10.1002/bmc.178pmid: 12378552
A liquid chromatographic (LC) method has been developed for the separation of 11 monohydroxybenzo(a)pyrenes (OH BaPs) positional isomers, and for their detection using electrospray ionization mass spectrometry (ESI‐MS). All OH BaPs isomers were separated on an octadecylsilyl (C18)‐bonded amorphous organosilica column utilizing gradient elution with acetonitrile–water and triethylamine (TEA) at pH 11.0 and determined by MS, except 2‐ and 8‐OH BaPs which were coeluted. The lower detection limits were in the range from 1.6 µg/L for 12‐OH BaP to 12 µg/L for 5‐OH BaP without any sample enrichment. The relative standard deviations of area response were in the range from 1.8% (9‐OH BaP) to 4.9% (12‐OH BaP) except for 9.4% (7‐OH BaP). The developed method was successfully applied to incubation mixtures of BaP and CYP1A1/epoxide hydrolase. This method identified 1‐, 3‐ and 9‐OH BaPs as the major metabolites, and 2‐ (and/or 8‐) and 12‐OH BaPs as the minor metabolites in the incubation mixture. Copyright © 2002 John Wiley & Sons, Ltd.
Enantiomeric separation of diuretics on a novel pirkle‐type chiral stationary phaseVercauteren, Ann; Weken, Guido Van der; Vankeirsbilck, Tineke; Aboul‐Enein, Hassan Y.; Baeyens, Willy R. G.
doi: 10.1002/bmc.179pmid: 12378553
A newly developed Pirkle‐type straight chiral stationary phase (CSP), based on the 3,5‐dinitrobenzoyl derivative of 1,2 diphenylethylene‐diamine and known as ULMO, has been successfully applied to the direct resolution of the enantiomers of several diuretics by liquid chromatography. In this study, the effect of changes in the mobile phase and the intrinsic stereoselective properties of this CSP towards a specific racemate are determined experimentally. A mobile phase consisting of n‐hexane and 2‐propanol appears most appropriate for the chiral separation of the tested diuretics on the ULMO‐column. Copyright © 2002 John Wiley & Sons, Ltd.
Supercritical fluid extraction for the separation of organochlorine pesticides residue in Angelica sinensisZhao, Chunjie; Hao, Guiming; Li, Huanxin; Chen, Yingjie
doi: 10.1002/bmc.180pmid: 12378554
A method involving the simultaneous extraction and separation of 12 organochlorine pesticides (OCPs) from Angelicae sinensis was developed using supercritical fluid extraction (SFE). The pesticides in the study were α‐, β‐, γ‐ and δ‐benzene hexachloride, PCNB (pentachloro‐ nitrobenzene), PCA (pentachloroaniline), HEPT (heptachlor), MPCPS (methyl‐pentachlorophenyl sulfide), pp′‐DDE (1,1‐dichloro‐2,2‐bis (p‐chlorophenyl) ethylene), op′‐DDT (1,1,1,‐trichloro‐2‐(o‐chlorophenyl)‐2‐(p‐chlorophenyl) ethane), pp′‐DDD (1,1‐dichloro‐2,2‐bis(p‐chlorophenyl) ethane), and pp′‐DDT (1,1,1,‐trichloro‐2,2‐bis (p‐chlorophenyl)ethane). The extraction conditions were optimized as follows: pure CO2, extraction pressure 15 MPa, extraction temperature 60°C, extraction time 20 min, and flow‐rate 1.5 mL/min. A GC method with electron capture detection was employed to determine the OCPs in Angelicae sinensis. An HPLC method was developed for the quantitative determination of active constituents. The SFE provided high decontamination rate of OCPs and low loss of active constituents in Angelicae sinensis. Copyright © 2002 John Wiley & Sons, Ltd.
Simultaneous HPLC determination of 5‐fluorouracil and its metabolites in plasma of cancer patientsCasale, F.; Canaparo, R.; Muntoni, E.; Serpe, L.; Zara, G.P.; Pepa, C. Della; Berno, E.; Costa, M.; Eandi, M.
doi: 10.1002/bmc.181pmid: 12378555
5‐Fluorouracil (5‐Fu) is a commonly used anticancer agent for treatment of solid tumours. Certain studies have reported conflicting results between individual plasma concentration levels and toxicity or therapeutic effects. For this reasons some authors proposed to evaluate the plasma levels of 5‐Fu metabolites 5‐fluorouridine, 5‐fluoro‐2′‐deoxyuridine and 5‐fluoro‐5,6‐dihydro‐uracil. The aim of the present work is to develop and validate a new HPLC method simultaneously determining 5‐fluorouracil and its three metabolites, to be used to study the plasma levels, therapeutic effects and toxicity in cancer patients. The analytes were separated on a 4.6 × 250 mm ODS1 (5 µm) not end‐capped column, operating at room temperature. Elution was performed under isocratic conditions, employing a 1.5 mM K3PO4 mobile phase (pH 5). 5‐Bromo‐5,6‐dihydro‐uracil was used as internal standard. The limits of quantitation were 0.5 µg/mL for 5‐fluorouracil, 1 µg/mL for 5‐fluoro‐5,6‐dihydro‐uracil, 3 µg/mL for 5‐fluoro‐2′‐deoxyuridine and 5‐fluorouridine; the stability, recovery, linearity, accuracy and specificity of the compounds were evaluated according to the criteria widely accepted. Using this method we measured plasma samples of 18 cancer patients treated with folinic acid (100 mg/m2) by intravenous administration, followed by an i.v. bolus of 5‐Fu (400 mg/m2). The concentration levels of 5‐fluorouracil and for 5‐fluoro‐5,6‐dihydro‐uracil were detectable in all the subjects while 5‐fluorouridine and 5‐fluoro‐2′‐deoxyuridine were present only in eight patients. Copyright © 2002 John Wiley & Sons, Ltd.
Investigation of propofol renal elimination by HPLC using supported liquid membrane procedure for sample preparationDawidowicz, Andrzej L.; Kalityński, Rafał; Trocewicz, Jerzy; Nestorowicz, Andrzej; Fijałkowska, Anna; Trela‐Stachurska, Katarzyna
doi: 10.1002/bmc.183pmid: 12378557
One of the least explored subjects in the research on the metabolism of a widely used anaesthetic, propofol, is its excretion in an unchanged form. According to literature, the estimated percentage of applied propofol eliminated intact via kidneys is lower than 0.3%. The present study shows the amount of propofol excreted in an unchanged form with urine collected during the first 48 h after anaesthesia in five patients undergoing elective intracranial procedures. The drug was concentrated and selectively isolated from urine samples by supported liquid membrane technique and determined by HPLC with fluorescence detection. The amount of unchanged propofol eliminated with urine was approximately (0.004 ± 0.002)% of the total applied dose. The obtained results may suggest that propofol in an unchanged form is not excreted by kidneys at all provided that all propofol determined in presented study originated from conjugates hydrolysis. Copyright © 2002 John Wiley & Sons, Ltd.
HPLC determination of phenylpropanolamine in pharmaceutical OTC preparationsNakashima, Kenichiro; Kanehara, Saori; Kaddoumi, Amal
doi: 10.1002/bmc.186pmid: 12378559
A convenient HPLC method to determine phenylpropanolamine (PPA) in addition to phenylephrine (PE) and chlorpheniramine (CPA) in commercially available over‐the‐counter (OTC) preparations has been developed. Sample solutions were prepared by dilution with water or methanol followed by filtration and direct injection into the HPLC system. The mobile phase was a mixture of methanol–acetonitrile–acetic acid (0.1 M)–triethylamine (20:20:60:0.6, v/v/v/v) containing sodium heptanesulfonate (0.5 mM) as an ion pair. The separation was achieved on a reversed‐phase ODS column with detection wavelength set at 254 nm. The compounds showed good linearity in the range 2.5–1000 µM with detection limits ranged from 0.13 to 0.48 µM. PE, caffeine and CPA were well separated when present together with PPA. The method was applied to the determination of PPA in pharmaceutical preparations including hard and soft capsules. Copyright © 2002 John Wiley & Sons, Ltd.
A modified HPLC method for the determination of ochratoxin A by fluorescence detectionAboul‐Enein, Hassan Y.; Kutluk, Özlem Banu; Altiokka, Göksel; Tunçel, Muzaffer
doi: 10.1002/bmc.187pmid: 12378560
A high‐performance liquid chromatographic method (HPLC) with fluorescent detector is described for the determination of ochratoxin A (OTA). A mobile phase consisting of acetonitrile:water:acetic acid (99:99:2, v/v/v) was used for the resolution of the compound on a C18 Hypersil column. The retention time for OTA and diflunisal which was used as an internal standard (IS) were 11.7 and 12.8 min, respectively. The method is selective, reliable, reproducable with relative standard deviation (RSD) of 1.70 and linear in the range of 2.5 × 10−9–1.5 × 10−8 M OTA. The limit of detection (LOD) and limit of quantification (LOQ) were 2.5 × 10−10 M corresponding to 0.1 ng mL−1 and 8.2 × 10−10 corresponding to 3.3 ng mL−1, respectively. Recovery studies were 81.2 ± 1.9 (SD). The method was applied for analysis of OTA in wheat, corn, red pepper, cheese and wine. The proposed method can be used for the routine analysis of OTA in food and animal feed. Copyright © 2002 John Wiley & Sons, Ltd.