References of "Chiap, Patrice"
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See detailStudy of adsorption effects in the analysis of pharmaceutical formulations by CE
Fotsing, L.; Fillet, Marianne ULg; Chiap, Patrice ULg et al

in Journal de Pharmacie de Belgique (1999), 54

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See detailAutomated Sample Preparation Techniques for the Determination of Drug Enantiomers in Biological Fluids Using Liquid Chromatography with Chiral Stationary Phases
Ceccato, Attilio ULg; Toussaint, B.; Chiap, Patrice ULg et al

in Enantiomer (1999), 4(3-4), 305-15

The determination of drug enantiomers has become of prime importance in the field of pharmaceutical and biomedical analysis. Liquid chromatography (LC) is one of the most frequently used techniques for ... [more ▼]

The determination of drug enantiomers has become of prime importance in the field of pharmaceutical and biomedical analysis. Liquid chromatography (LC) is one of the most frequently used techniques for achieving the separation and quantitation of the enantiomers of drug compounds. In the bioanalytical field, the integrated systems present an interesting alternative to time-consuming sample preparation techniques such as liquid-liquid extraction. Solid phase extraction (SPE) on disposable cartridges, dialysis or column switching are sample preparation techniques that can be fully automated and applied to enantioselective analysis in biological fluids. The selection of the most appropriate LC mode and chiral stationary phase for enantioseparations in bioanalysis is discussed and some aspects of these automated sample preparation procedures are compared, such as selectivity, detectability, elution of the analytes from the extraction sorbent, sample volume and analyte stability. [less ▲]

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See detailThe effect of hydroxypropyl-b-cyclodextrins on the pharamacokinetics of albendazole in sheep
Evrard, Brigitte ULg; De Tullio, Pascal ULg; Chiap, Patrice ULg et al

in Proceedings of 26th International Symposium on Controlled Release of Bioactive Materials (1999)

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See detailElimination of adsorption effects in the analysis of water-soluble vitamins in pharmaceutical formulations by capillary electrophoresis.
Fotsing, Lucas; Fillet, Marianne ULg; Chiap, Patrice ULg et al

in Journal of Chromatography. A (1999), 853(1-2), 391-401

A tendency to an increase in migration times was observed when different water-soluble vitamins were analysed repeatedly in pharmaceutical preparations by capillary electrophoresis. In order to better ... [more ▼]

A tendency to an increase in migration times was observed when different water-soluble vitamins were analysed repeatedly in pharmaceutical preparations by capillary electrophoresis. In order to better understand the origin of this effect, the influence of the vitamins and the excipients, such as cellulose derivatives, was investigated. These studies indicated that the increase in analyte migration times was most probably due to the adsorption of different kinds of constituents to the capillary wall. Different rinsing procedures were tested in order to eliminate these unfavourable effects. A rinse of the capillary with a 25 mM sodium dodecyl sulfate (SDS) solution in the running buffer between successive runs was found to be particularly effective when the analysis was performed by free solution capillary zone electrophoresis (CZE). When the vitamins were determined by micellar electrokinetic chromatography (MEKC) using SDS as surfactant, a short capillary rinse with the running buffer was sufficient to obtain reproducible migration times. The CZE and MEKC methods developed were validated and compared. Both methods could be applied to the determination of water-soluble vitamins in different multivitamin formulations. [less ▲]

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See detailInterlaboratory studies on two high-performance liquid chromatographic assays for tylosin (tartrate)
Vander Heyden, Y.; Saevels, J.; Roets, E. et al

in Journal of Chromatography. A (1999), 830(1), 3-28

An interlaboratory study was performed on two high-performance liquid chromatographic methods to determine tylosin. The first method is a reversed-phase HPLC on a C-18 column, while the second is a method ... [more ▼]

An interlaboratory study was performed on two high-performance liquid chromatographic methods to determine tylosin. The first method is a reversed-phase HPLC on a C-18 column, while the second is a method using a polymeric stationary phase. The first method is described in several pharmacopoeia monographs on tylosin, to determine the composition of a tylosin mixture, while the second method is recently proposed to determine both the composition and the contents in such a mixture. The interlaboratory studies were set-up and interpreted according to ISO guidelines. This paper is written as a tutorial type of article explaining the principles and methods of these guidelines. The results of both methods were compared. Both were found to have disadvantages but in general the old method is still preferred, both for composition determination and to assay the components. (C) 1999 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailThe SFSTP guide on the validation of chromatographic methods for drug bioanalysis: from the Washington Conference to the laboratory
Hubert, Philippe ULg; Chiap, Patrice ULg; Crommen, Jacques ULg et al

in Analytica Chimica Acta (1999), 391(2), 135-148

On the basis of the guidelines given in the Washington Conference report and the ICH (International Conference of Harmonisation) recommendations some suggestions about experimental design and data ... [more ▼]

On the basis of the guidelines given in the Washington Conference report and the ICH (International Conference of Harmonisation) recommendations some suggestions about experimental design and data evaluation are proposed by an SFSTP Commission dedicated to the validation of chromatographic methods in bioanalysis. In a series of meetings, members of this Commission have tried to elaborate a rational, practical and statistically reliable strategy to assure the quality of the analytical results generated. This strategy has been formalised in a guide and the main suggestions made by the Commission are summarised in the present paper. The SFSTP guide has been produced to help analysts from the pharmaceutical industry to validate their bioanalytical methods, It is the result of a consensus between professionals having expertise in bioanalytical and/or statistical fields. The suggestions presented in this paper should therefore help the analyst to design and perform the minimum number of validation experiments needed to obtain all the required information to establish and demonstrate the reliability of its analytical procedure. The SFSTP guide suggests a validation strategy in two steps: a pre-validation and the validation itself. An experimental design is described for each of these steps and the main aspects discussed in the paper are related to the selection of the most appropriate calibration model to fit experimental data and the most suitable way to determine the limit(s) of quantitation and subsequently the calibration range as well as the optimum number of experiments to be performed in the validation phase. (C) 1999 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailValidation of an automated method for the liquid chromatographic determination of atenolol in plasma: application of a new validation protocol
Chiap, Patrice ULg; Hubert, Philippe ULg; Boulanger, Bruno ULg et al

in Analytica Chimica Acta (1999), 391(2), 227-238

In order to test the applicability of a new strategy by a Commission of the Societe Francaise des Sciences et Techniques Pharmaceutiques (SFSTP) for the validation of bioanalytical methods, an automated ... [more ▼]

In order to test the applicability of a new strategy by a Commission of the Societe Francaise des Sciences et Techniques Pharmaceutiques (SFSTP) for the validation of bioanalytical methods, an automated method was developed for the determination of atenolol in human plasma. This method was based on the use of dialysis as sample purification step, followed by enrichment of the dialysate on a precolumn and liquid chromatographic analysis. All sample handling operations were carried out automatically by means of an ASTED system. Atenolol and its internal standard (sotalol) were separated on a C-8 column with a mixture of pH 7.0 phosphate buffer containing 1-octanesulphonate and methanol (81/19; v:v) as mobile phase and monitored photometrically at 225 nm. The validation strategy comprises two steps. The experiments performed during the first step, the so called pre-validation step, have permitted the selection of the most appropriate model for the calibration curve by means of a decision tree, i.e. a least squares regression model obtained after transformation of data (square root in this case), the estimation of the limit of quantitation at 25 ng/ml by means of an accuracy profile, the determination of the calibration range (from 25 to 1000 ng/ml), the estimation of the limit of detection at 9 ng/ml and the calculation of the mean extraction efficiency (about 65%). The second step is the validation itself, comprising the evaluation of method selectivity towards endogenous components, the confirmation of the limit of quantitation, the verification of linearity and the assessment of method precision (repeatability and intermediate precision) as well as accuracy using quality control samples at different concentration levels over the range investigated. The relative standard deviation values for repeatability and intermediate precision were between 2.7% and 9.0%. Moreover, the method was found to be accurate. Indeed, the 95% one-sided confidence limits of the mean recovery did not exceed the acceptance limits of 80% and 120%. (C) 1999 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailSimultaneous Determination of Methylphenobarbital Enantiomers and Phenobarbital in Human Plasma by on-Line Coupling of an Achiral Precolumn to a Chiral Liquid Chromatographic Column
Ceccato, Attilio ULg; Boulanger, Bruno ULg; Chiap, Patrice ULg et al

in Journal of Chromatography. A (1998), 819(1-2), 143-53

A fully automated liquid chromatographic (LC) method for the simultaneous determination of methylphenobarbital enantiomers and phenobarbital in human plasma has been developed. The method is based on the ... [more ▼]

A fully automated liquid chromatographic (LC) method for the simultaneous determination of methylphenobarbital enantiomers and phenobarbital in human plasma has been developed. The method is based on the use of a precolumn packed with an internal-surface reversed-phase packing material (LiChrospher ADS) for sample clean-up coupled to LC analysis on a cellulose tris(4-methylbenzoate) based chiral stationary phase (Chiralcel OJ-R). A 100-microliter plasma sample was injected directly on the precolumn packed with LiChrospher RP-18 ADS using a mixture of pH 5.0 phosphate buffer-methanol (97:3, v/v) as washing liquid. The analytes were then eluted in the back-flush mode with the LC mobile phase. The enantiomeric separation of methylphenobarbital was achieved on Chiralcel OJ-R). The retention times were modelled using a D-optimal design with ten experimental points in order to optimise the LC mobile phase for the separation of phenobarbital from the enantiomers of mephobarbital. The factors selected were the acetonitrile content, the pH and the sodium perchlorate concentration in the mobile phase. A Derringer's desirability function was used to find an optimal and robust solution within the experimental domain. The mobile phase selected consisted of a mixture of pH 7.0 phosphate buffer-acetonitrile (60:40, v/v). The elution profiles of phenobarbital, methylphenobarbital and blank plasma samples on the precolumn and the time needed for analyte transfer from the precolumn to the analytical column were then determined. Finally, the method developed was validated. [less ▲]

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See detailValidation of an automated method for the LC determination of atenolol in plasma : application of a new validation strategy
Chiap, Patrice ULg; Boulanger, Bruno ULg; Bimazubute, Marcel et al

in Journal de Pharmacie de Belgique (1998), 53

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