References of "Chiap, Patrice"
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See detailStatistical analysis of the validation results: diagnostic or decision tools
Hubert, Philippe ULg; Chiap, Patrice ULg; Dormal, C. et al

Conference (2002)

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See detailOn-Line Coupling of Partial Filling-Capillary Zone Electrophoresis with Mass Spectrometry for the Separation of Clenbuterol Enantiomers
Toussaint, B.; Palmer, M.; Chiap, Patrice ULg et al

in Electrophoresis (2001), 22(7), 1363-72

The on-line coupling of capillary zone electrophoresis with mass spectrometry (CZE-MS) for the separation of enantiomers is hampered by the presence of nonvolatile chiral selectors such as cyclodextrins ... [more ▼]

The on-line coupling of capillary zone electrophoresis with mass spectrometry (CZE-MS) for the separation of enantiomers is hampered by the presence of nonvolatile chiral selectors such as cyclodextrins in the separation buffer. This problem can be overcome by use of the partial filling technique where only a part of the capillary is filled with the separation buffer containing chiral selectors. Since the electroosmotic flow is almost completely suppressed at acidic pH, that dimethyl-beta-cyclodextrin is neutral, no free cyclodextrin would reach the MS detector when using a partially filled capillary. By this method, clenbuterol enantiomers were successfully resolved and separated from salbutamol (internal standard) in aqueous solution and in plasma samples. A solid-phase extraction (SPE) was used for the preparation of plasma samples before analysis. [less ▲]

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See detailDevelopment and Validation of an Automated Method for the Liquid Chromatographic Determination of Sotalol in Plasma Using Dialysis and Trace Enrichment on a Cation-Exchange Pre-Column as on-Line Sample Preparation
Chiap, Patrice ULg; Ceccato, Attilio ULg; Miralles Buraglia, B. et al

in Journal of Pharmaceutical & Biomedical Analysis (2001), 24(5-6), 801-14

A fully automated method for the determination of sotalol in human plasma was developed, involving dialysis through a cellulose acetate membrane, clean-up and enrichment of the dialysate on a strong ... [more ▼]

A fully automated method for the determination of sotalol in human plasma was developed, involving dialysis through a cellulose acetate membrane, clean-up and enrichment of the dialysate on a strong cation-exchange pre-column and subsequent liquid chromatographic (LC) analysis with UV detection. All sample handling operations were carried out by means of an ASTED system. Before starting dialysis, the trace enrichment column (TEC) was conditioned. The plasma sample, to which the internal standard (atenolol) was automatically added, was then loaded in the donor channel and was kept static while the dialysis liquid, consisting of 0.017 M acetic acid, was passed through the acceptor channel in successive pulses. After each pulse, the dialysate was dispensed onto the TEC. When dialysis was discontinued, the analytes were eluted from the TEC by the LC mobile phase by rotation of a switching valve and transferred to the analytical column packed with octyl silica. The LC mobile phase was a mixture of methanol and pH 7.0 phosphate buffer containing 1-octanesulfonate at a concentration of 7.5 x 10(-4) M (19:81; v/v). The UV detection was performed at 230 nm. The influence of several parameters of the dialysis and trace enrichment processes on analyte recovery and method selectivity was investigated. The method was then validated. The mean absolute recovery for sotalol was about 60%. The limit of quantitation was 25 ng/ml and R.S.D. for repeatability and intermediate precision obtained at a concentration level of 50 ng/ml were 4.3 and 5.8%, respectively. [less ▲]

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See detailLiquid chromatographic analysis of local anesthetics in human plasma after sample preparation by on-line dialysis. Optimization by use of experimental design
Chiap, Patrice ULg; Boulanger, Bruno ULg; Fotsing, Lucas ULg et al

in Chromatographia (2001), 53(11-12), 678-686

A fully automated method involving dialysis, clean-up and enrichment of the dialysate on a pre-column packed with a strong cation-exchange phase, and subsequent liquid chromatographic (LC) analysis with ... [more ▼]

A fully automated method involving dialysis, clean-up and enrichment of the dialysate on a pre-column packed with a strong cation-exchange phase, and subsequent liquid chromatographic (LC) analysis with UV detection at 220 nm has been developed for the determination of local anesthetics (prilocaine, mepivacaine, and bupivacaine) in human plasma. All sample-handling operations were executed automatically by means of an Asted XI system. To identify the most important conditions affecting analyte recovery from the dialysis and trace-enrichment processes, a seven-factor D-optimal design with 16 experimental points was elaborated as a screening test A four-factor D-optimal design with 24 experimental points was then used to predict and optimize analyte recovery. Derringer's desirability function was also used to deduce optimum conditions for analyte recovery and dialysis time within the experimental domain. Finally, the method developed was validated. Mean recoveries were approximately 72% for bupivacaine and approximately 67% for mepivacaine and prilocaine. The limits of quantification were 28 ng mL(-1) for bupivacaine and 25 ng mL(-1) for mepivacaine and prilocaine. [less ▲]

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See detailDetermination of Albendazole and Its Main Metabolites in Ovine Plasma by Liquid Chromatography with Dialysis as an Integrated Sample Preparation Technique
Chiap, Patrice ULg; Evrard, Brigitte ULg; Bimazubute, M. A. et al

in Journal of Chromatography. A (2000), 870(1-2), 121-34

Albendazole is a benzimidazole derivative with a broad-spectrum activity against human and animal helminth parasites. In order to determine the main pharmacokinetic parameters in sheep after oral and ... [more ▼]

Albendazole is a benzimidazole derivative with a broad-spectrum activity against human and animal helminth parasites. In order to determine the main pharmacokinetic parameters in sheep after oral and intravenous administration of a new formulation of albendazole (an aqueous solution), a fully automated method was developed for the determination of this drug and its main metabolites, albendazole sulfoxide (active metabolite) and sulfone in ovine plasma. This method involves dialysis as purification step, followed by enrichment of the dialysate on a precolumn and liquid chromatography (LC). All sample handling operations were executed automatically by means of an ASTED XL system. After conditioning of the trace enrichment column (TEC) packed with octadecyl silica with pH 6.0 phosphate buffer containing sodium azide, the plasma sample, in which a protein releasing reagent (1 M HCl) containing Triton X-100 was automatically added, was loaded in the donor channel and dialysed on a cellulose acetate membrane in the static-pulsed mode. The dialysis liquid consisted of pH 2.5 phosphate buffer. By rotation of a switching valve, the analytes were eluted from the TEC in the back-flush mode by the LC mobile phase and transferred to the analytical column, packed with octyl silica. The chromatographic separation was performed at 35 degrees C and the analytes were monitored photometrically at 295 nm. Due to the differences in hydrophobic character between albendazole and its metabolites, a gradient elution was applied. The mobile phase consisted of a mixture of acetonitrile and pH 6.0 phosphate buffer. The proportion of organic modifier was increased from 10.0 to 50.1% in 12.30 min, then from 50.1 to 66.9% in 1.70 min. First, the gradient conditions and the temperature were optimised for the LC separation using the DryLab software. Then, the influence of some parameters of the dialysis process on analyte recovery was investigated. Finally, the method developed was validated. The mean recoveries for albendazole and its metabolites were about 70 and 65%, respectively. The limits of quantification for albendazole and its metabolites were 10 and 7.5 ng/ml, respectively. [less ▲]

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See detailAutomated Liquid Chromatographic Determination of Atenolol in Plasma Using Dialysis and Trace Enrichment on a Cation-Exchange Precolumn for Sample Handling
Chiap, Patrice ULg; Buraglia, B. M.; Ceccato, Attilio ULg et al

in Journal of Chromatography. B : Biomedical Sciences and Applications (2000), 739(1), 205-17

A fully automated method involving dialysis combined with trace enrichment was developed for the liquid chromatographic (LC) determination of atenolol, a hydrophilic beta-blocking agent, in human plasma ... [more ▼]

A fully automated method involving dialysis combined with trace enrichment was developed for the liquid chromatographic (LC) determination of atenolol, a hydrophilic beta-blocking agent, in human plasma. The plasma samples were dialysed on a cellulose acetate membrane and the dialysate was reconcentrated on a short trace enrichment column (TEC) packed with a strong cation-exchange material. All sample handling operations can be executed automatically by a sample processor (ASTED system). After TEC conditioning, the plasma sample, to which the internal standard (sotalol, another hydrophilic beta-blocker) was automatically added, was introduced in the donor channel and dialysed in the static/pulsed mode. The dialysis liquid consisted of 4.3 mM phosphoric acid. When the dialysis process was discontinued, the analytes were eluted from the TEC in the back-flush mode by the LC mobile phase and transferred to the analytical column, packed with octyl silica. The LC mobile phase consisted of phosphate buffer, pH 7.0-methanol (81:19; v/v) with 1-octanesulfonate. Atenolol and the internal standard were monitored photometrically at 225 nm. The different parameters influencing the dialysis and trace enrichment processes were optimised with respect to analyte recovery. The influence of two different kinds of cation-exchange material on analyte recovery and peak efficiency was also studied. The method was then validated in the concentration range 25-1000 ng/ml. The mean recovery for atenolol was 65% and the limit of quantitation was 25 ng/ml. [less ▲]

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