References of "Servais, Anne-Catherine"
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See detailOptimization of the liquid chromatography enantioseparation of chiral acidic compounds using cellulose tris(3-chloro-4-methylphenylcarbamate) as chiral selector and polar organic mobile phases.
Dossou, K. S. S.; Farcas, Elena ULg; Servais, Anne-Catherine ULg et al

in Journal of Chromatography. A (2012), 1234

The LC enantioseparation of chiral acidic and zwitterionic drugs selected as model compounds was optimized using chlorine containing cellulose based chiral stationary phases and polar organic mobile ... [more ▼]

The LC enantioseparation of chiral acidic and zwitterionic drugs selected as model compounds was optimized using chlorine containing cellulose based chiral stationary phases and polar organic mobile phases. The main solvent of the mobile phase was acetonitrile, the temperature was settled at 25 degrees C and a stationary phase with cellulose tris(3-chloro-4-methylphenylcarbamate) as chiral selector (3-Cl-4-Me-PC) was selected. In the screening step, the nature and concentration of both acidic and basic additives were found to have a significant effect on retention, selectivity and resolution. Acetic acid (AcA) was selected as acidic additive for the optimization step since it could lead to the enantioseparation of more acidic compounds than trifluoroacetic acid (TFA) and formic acid (FA), while among the three basic additives tested, diethylamine (DEA) most often gave better results with respect to enantioresolution and selectivity than butylamine (BuA) and triethylamine (TEA). The optimization was performed using a central composite face-centered design with two factors, namely the concentration of acetic acid (0.1-0.3%) and the concentration of DEA (0.01-0.1%) in the mobile phase. On the basis of the results obtained in the screening and optimization steps, a strategy for the rapid development of methods for the enantioseparation of acidic or neutral compounds was proposed. [less ▲]

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See detailCombination of capillary electrophoresis, molecular modelling and nuclear magnetic resonance to study the interaction mechanisms between single-isomer anionic cyclodextrin derivatives and basic drug enantiomers in a methanolic background electrolyte.
Servais, Anne-Catherine ULg; Rousseau, Anne; Dive, Georges ULg et al

in Journal of Chromatography. A (2012), 1232

In order to improve our knowledge of the mechanisms of enantiomer recognition pattern in nonaqueous systems, an approach combining nonaqueous CE (NACE), molecular modelling and NMR was undertaken ... [more ▼]

In order to improve our knowledge of the mechanisms of enantiomer recognition pattern in nonaqueous systems, an approach combining nonaqueous CE (NACE), molecular modelling and NMR was undertaken. Bupivacaine and propranolol were selected as model compounds and their interactions with two single-isomer highly charged beta-CD derivatives, namely heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-CD (HDMS-beta-CD) and heptakis(2,3-di-O-acetyl-6-O-sulfo)-beta-CD (HDAS-beta-CD), were studied. The CD-bupivacaine complexes were evaluated by 2-D Rotating-frame Overhauser Effect SpectroscopY (ROESY) experiments. From these experiments, it can be assumed that inclusion complexes are not formed, whatever the CD derivative used. Molecular modelling was performed at the RHF/MINI-1 or B3LYP/6-31G(d) level. External as well as inclusion type complexes with the alkyl chain of propranolol into both CD cavities were located. Interaction energies calculated for bupivacaine and propranolol correlated with the enantiomer migration order observed in the NACE experiments using both anionic CD derivatives. The interaction of propranolol with HDMS-beta-CD or HDAS-beta-CD gives rise to a family of external and inclusion complexes in which some are more probably obtained. [less ▲]

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See detailOptimization of micro-HPLC peak focusing for the detection and quantification of low hepcidin concentrations.
Mansion, François ULg; Chiap, Patrice ULg; Houbart, Virginie ULg et al

in Journal of Separation Science (2011), 34(15), 1820-1827

Micro-high-performance liquid chromatography is a miniaturized, economic and ecological chromatographic system allowing the use of reduced size chromatographic columns. Coupled with electrospray ... [more ▼]

Micro-high-performance liquid chromatography is a miniaturized, economic and ecological chromatographic system allowing the use of reduced size chromatographic columns. Coupled with electrospray ionization tandem mass spectrometry, this technique can be used to detect and quantify low concentrations of peptides. In this study, hepcidin was used as the model compound and analysed using octadecylsilica stationary phase by means of a gradient elution mode at a flow rate of 4 muL/min. Several parameters were studied to optimize peak focusing. Using the methodology of experimental design, the mobile-phase gradient conditions and the sample composition were optimized in order to maximize the sensitivity and minimize retention time. Stability of the target peptide in solution was also demonstrated. [less ▲]

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See detailDetermination of enantiomeric purity of S-amlodipine by chiral LC with emphasis on reversal of enantiomer elution order.
Dossou, Katina Sourou Sylvestre ULg; Edorh, P. A.; Chiap, Patrice ULg et al

in Journal of Separation Science (2011), 34

An LC method was developed and prevalidated for the enantiomeric purity determination of S-amlodipine in polar organic solvent chromatography using a chlorine-containing cellulose-based chiral stationary ... [more ▼]

An LC method was developed and prevalidated for the enantiomeric purity determination of S-amlodipine in polar organic solvent chromatography using a chlorine-containing cellulose-based chiral stationary phase (CSP). The concentration of formic acid (FA) (0.01-0.2%) in the mobile phase containing acetonitrile as the main solvent was found to influence the elution order of amlodipine enantiomers as well as the enantioresolution. A reversal of the enantiomer elution order of amlodipine was only observed with chiral stationary phases with both electron-withdrawing (chloro) and electron-donating groups (methyl) on the phenyl moieties of the chiral selector, namely cellulose tris(3-chloro-4-methylphenylcarbamate) and cellulose tris(4-chloro-3-methylphenylcarbamate). The highest enantioresolution (R(s) : 4.1) value was obtained at the lowest FA concentration (0.01%) using cellulose tris(4-chloro-3-methylphenylcarbamate) as the chiral selector and the enantiomeric impurity, R-amlodipine, eluted first under these conditions. Therefore, the mobile phase selected for the prevalidation of the method consisted of ACN/0.1% DEA/0.01% FA and the temperature was set at 25 degrees C. The method was prevalidated by means of the strategy based on the total measurement error and the accuracy profile. The method was found to be selective and the limit of quantification was found to be about 0.05% for R-amlodipine, while the limit of detection was close to 0.02%. [less ▲]

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See detailEvaluation of chlorine containing cellulose-based chiral stationary phases for the LC enantioseparation of basic pharmaceuticals using polar non-aqueous mobile phases.
Dossou, Katina Sourou Sylvestre ULg; CHIAP, Patrice ULg; Servais, Anne-Catherine ULg et al

in Journal of Separation Science (2011), 34(6), 617-22

The discrimination ability of three cellulose-based chiral stationary phases (CSPs) was evaluated towards the enantiomers of basic drugs, using ACN as the main solvent in polar organic mobile phases. The ... [more ▼]

The discrimination ability of three cellulose-based chiral stationary phases (CSPs) was evaluated towards the enantiomers of basic drugs, using ACN as the main solvent in polar organic mobile phases. The study was focused on CSPs containing cellulose tris(3-chloro-4-methylphenylcarbamate) (3-Cl-4-MePC), cellulose tris(4-chloro-3-methylphenylcarbamate) (4-Cl-3-MePC) or cellulose tris(3,5-dichlorophenylcarbamate) (3,5-diClPC) as the chiral selector. The behaviour of these CSPs was studied systematically in order to investigate the influence of the presence and position of the chlorine substituents on the phenylcarbamate moieties on the retention and resolution of the enantiomers. The evaluation was made with three different generic mobile phases, namely ACN/0.1%DEA/0.1% TFA (DEA, diethylamine), ACN/0.1%DEA/0.2% FA and ACN/0.1%DEA/0.2%AcA, deduced from the previous study. The nature of the acidic additive and of the chiral selector was found to be particularly important for the retention and enantioresolution of these basic compounds. High-resolution values could be obtained for most studied enantiomers with these CSPs, clearly demonstrating the interest of using them in combination with polar organic mobile phases. However, significant differences in enantioresolution between the CSPs have been observed for many compounds, indicating that these phases seem to be quite complementary. [less ▲]

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See detailDevelopment and validation of a LC method for the enantiomeric purity determination of S-ropivacaine in a pharmaceutical formulation using a recently commercialized cellulose-based chiral stationary phase and polar non-aqueous mobile phase.
Dossou, Katina Sourou Sylvestre ULg; CHIAP, Patrice ULg; Servais, Anne-Catherine ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 54(4), 687-93

Ropivacaine is the first enantiomerically pure long-acting local anaesthetic used for surgical anaesthesia and post-operative pain relief. A liquid chromatographic (LC) method using acetonitrile as the ... [more ▼]

Ropivacaine is the first enantiomerically pure long-acting local anaesthetic used for surgical anaesthesia and post-operative pain relief. A liquid chromatographic (LC) method using acetonitrile as the main solvent and cellulose tris(4-chloro-3-methylphenylcarbamate) coated on silica as chiral stationary phase was successfully developed and applied for the enantiomeric purity determination of S-ropivacaine in a pharmaceutical formulation (Naropin((R))). The key role played by the acidic additive (trifluoroacetic acid or formic acid) in the enantioseparation of basic drugs in these LC systems was demonstrated by the reversal of ropivacaine enantiomers elution order observed when both acids were compared. In order to elute the enantiomeric impurity (R-ropivacaine) before S-ropivacaine, formic acid (FA) was selected. The temperature and the percentages of acidic additive and hexane in the mobile phase were found to significantly influence the retention and resolution of these enantiomers. The optimized mobile phase consisted of ACN/0.1% DEA/0.2% FA/5% hexane (v/v/v/v). The temperature was set at 35 degrees C to avoid the interference from a peak system related to the presence of water in the sample on ropivacaine enantiomers. The LC method was then fully validated applying the strategy based on total measurement error and accuracy profiles. The accuracy profile obtained by linear regression after square root transformation was selected, the acceptance limits being settled at +/-10% for the intended use of this analytical method. The relative bias was lower than 1.5%, while the RSD values for repeatability and intermediate precision were both below 1.0%. The limit of detection (LOD) and the limit of quantification (LOQ) were found to be about 0.2 and 1.0 mug/mL, respectively, corresponding to 0.02 and 0.1% of the enantiomeric impurity in S-ropivacaine. [less ▲]

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See detailPre-study and in-study validation of a SPE-LC-MS-MS method for the determination of 5-S-cysteinyldopa, a melanoma biomarker, in human plasma.
Martin, Gaelle; Mansion, François ULg; Houbart, Virginie ULg et al

in Talanta (2011), 84(2), 280-6

The incidence of malignant melanoma has increased over the past decades, particularly in Caucasian population. This disease presents defavourable prognosis in terms of survey, especially when detection ... [more ▼]

The incidence of malignant melanoma has increased over the past decades, particularly in Caucasian population. This disease presents defavourable prognosis in terms of survey, especially when detection occurs at the metastatic phase. Reliable analytical methods for biomarker determination are thus an interesting tool in pathology detection and follow-up. In this context, a method using SPE-LC-ESI-MS-MS for the determination of 5-S-cysteinyldopa (5-SCD) in human plasma was optimized. The presence of matrix effect was investigated in details while 5-SCD stability was studied according to FDA requirements for the validation of bioanalytical methods. Pre-study and in-study validations of the entire method were then successfully performed by applying the approach based on total measurement error and accuracy profiles over a concentration ranges from 1.6 to 200 ng/ml. Good results with respect to accuracy, trueness and precision were obtained. The maximum risk of observing future measurements falling outside the acceptance limits during routine analysis was also estimated. [less ▲]

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See detailGeneric systems for the enantioseparation of basic drugs in NACE using single-isomer anionic CDs
Rousseau, Anne ULg; Gillotin, Florian; Chiap, Patrice ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 54

The enantioseparation of ten basic drugs was evaluated in NACE systems using heptakis(2-O-methyl-3-O-acetyl-6-O-sulfo)-β-CD (HMAS-β-CD). For this purpose, a D-optimal design with 21 experimental points ... [more ▼]

The enantioseparation of ten basic drugs was evaluated in NACE systems using heptakis(2-O-methyl-3-O-acetyl-6-O-sulfo)-β-CD (HMAS-β-CD). For this purpose, a D-optimal design with 21 experimental points was applied. Four antifungal agents (econazole, isoconazole, miconazole, sulconazole), three local anesthetics (bupivacaine, mepivacaine and prilocaine), two sympathomimetics (salbutamol and terbutaline) and one β-blocker (carvedilol) were selected as basic model analytes. The influence on the enantiomeric resolution of anionic CD and BGE anion concentrations as well as the BGE anion nature was investigated. For all studied analytes, the enantiomeric resolution was shown to be significantly influenced by the CD concentration. Based on the observed results, a generic NACE system was recommended, namely 20 mM HMAS-β-CD and 10 mM ammonium camphorSO3- in methanol acidified with 0.75 M formic acid. Moreover, this NACE system was compared to previous conditions with heptakis(2,3-di-O-methyl-6-O-sulfo)-β-CD (HDMS-β-CD) or heptakis(2,3-di-O-acetyl-6-O-sulfo)-β-CD (HDAS-β-CD). Finally, two generic systems using either HDAS-β-CD or HMAS-β-CD were proposed and evaluated for the enantioseparation of ketamine and norketamine after incubation of ketamine in phenobarbital-induced male rat liver microsomes systems. [less ▲]

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See detailA DESIGN SPACE APPROACH TO DEVELOP A GENERIC CE METHOD FOR THE SEPARATION OF 19 ANTIMALARIAL DRUGS
Lamalle, Caroline ULg; Marini Djang'Eing'A, Roland ULg; Debrus, Benjamin ULg et al

Poster (2010, September)

This project consists in analysing different molecules used against malaria by capillary electrophoresis (CE).

Detailed reference viewed: 72 (19 ULg)