References of "Crommen, Jacques"
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See detailCapillary electrophoresis in the context of drug discovery.
Farcas, Elena ULg; Pochet, Lionel; Crommen, Jacques ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2017)

Capillary Electrophoresis is a very efficient and resolutive separation technique used for many years in the analytical field. Despite all its assets, CE remains poorly used in drug discovery. This can be ... [more ▼]

Capillary Electrophoresis is a very efficient and resolutive separation technique used for many years in the analytical field. Despite all its assets, CE remains poorly used in drug discovery. This can be explained by the relatively low number of experienced CE practitioners, the maturity of HPLC in the pharmaceutical industry and some intrinsic limitations of the technique. The objective of this review is to focus our attention on recent developments of this technique in three different drug discovery areas: bioassays, drug-plasma interactions and drug metabolism studies. These developments were based on two important abilities of CE: the capacity to measure non-covalent interactions in solution and the ability to use a portion of the capillary as a reactor while the rest of the capillary is used for the separation of the product of the reaction. [less ▲]

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See detailEnantioselective capillary electrophoresis-mass spectrometry of amino acids in cerebrospinal fluid using a chiral derivatizing agent and volatile surfactant.
Prior, A.; Moldovan, R. C.; Crommen, Jacques ULg et al

in Analytica Chimica Acta (2016), 940

The sensitivity of coupled enantioselective capillary electrophoresis-mass spectrometry (CE-MS) of amino acids (AAs) is often hampered by the chiral selectors in the background electrolyte (BGE). A new ... [more ▼]

The sensitivity of coupled enantioselective capillary electrophoresis-mass spectrometry (CE-MS) of amino acids (AAs) is often hampered by the chiral selectors in the background electrolyte (BGE). A new method is presented in which the use of a chiral selector is circumvented by employing (+)-1-(9-fluorenyl)ethyl chloroformate (FLEC) as chiral AA derivatizing agent and ammonium perfluorooctanoate (APFO) as a volatile pseudostationary phase for separation of the formed diastereomers. Efficient AA derivatization with FLEC was completed within 10 min. Infusion experiments showed that the APFO concentration hardly affects the MS response of FLEC-AAs and presents significantly less ion suppression than equal concentrations of ammonium acetate. The effect of the pH and APFO concentration of the BGE and the capillary temperature were studied in order to achieve optimized enantioseparation. Optimization of CE-MS parameters, such as sheath-liquid composition and flow rate, ESI and MS settings was performed in order to prevent analyte fragmentation and achieve sensitive detection. Selective detection and quantification of 14 chiral proteinogenic AAs was achieved with chiral resolution between 1.2 and 8.6, and limits of detection ranging from 130 to 630 nM injected concentration. Aspartic acid and glutamic acid were detected, but not enantioseparated. The optimized method was applied to the analysis of chiral AAs in cerebrospinal fluid (CSF). Good linearity (R(2) > 0.99) and acceptable peak area and electrophoretic mobility repeatability (RSDs below 21% and 2.4%, respectively) were achieved for the chiral proteinogenic AAs, with sensitivity and chiral resolution mostly similar to obtained for standard solutions. Next to l-AAs, endogenous levels of d-serine and d-glutamine could be measured in CSF revealing enantiomeric ratios of 4.8%-8.0% and 0.34%-0.74%, respectively, and indicating the method's potential for the analysis of low concentrations of d-AAs in presence of abundant l-AAs. [less ▲]

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See detailAnalysis of protamine peptides in insulin pharmaceutical formulations by capillary electrophoresis.
Lamalle, Caroline; Servais, Anne-Catherine ULg; Demelenne, Alice ULg et al

in Journal of Separation Science (2016), 39(6), 1189-94

Protamines are a group of highly basic peptides that are sometimes added to insulin formulations to prolong the pharmacological action. In this study, different methods were investigated to identify ... [more ▼]

Protamines are a group of highly basic peptides that are sometimes added to insulin formulations to prolong the pharmacological action. In this study, different methods were investigated to identify protamine in insulin formulations. Capillary electrophoresis in aqueous and non-aqueous media was tested to separate these peptides with very close amino acid sequences. Different buffers (phosphate or formate, both acidified) and various additives (principally negatively charged and neutral surfactants) were investigated to optimize peptide separation. Finally, a micellar electrokinetic capillary chromatography method using a capillary of 120 cm effective length and an aqueous background electrolyte made up of 100 mM phosphate buffer (pH 2) and 50 mM Thesit(R) gave the best results, providing the separation of the four major protamine peptides within 25 min. [less ▲]

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See detailLiquid chromatography separation of the chiral prodrug eslicarbazepine acetate and its main metabolites in polar organic mode. Application to their analysis after in vitro metabolism.
Servais, Anne-Catherine ULg; Janicot, Bertrand; Takam, Arnold et al

in Journal of Chromatography. A (2016), 1467

A LC method using a chiral stationary phase (CSP) with cellulose tris(3-chloro-4-methylphenylcarbamate) as chiral selector in polar organic mode (POM) was developed for the separation of the ... [more ▼]

A LC method using a chiral stationary phase (CSP) with cellulose tris(3-chloro-4-methylphenylcarbamate) as chiral selector in polar organic mode (POM) was developed for the separation of the biopharmaceutic classification system (BCS) class II chiral prodrug eslicarbazepine acetate (ESL) and its main metabolites, namely eslicarbazepine, its optical antipode, (R)-licarbazepine, and the achiral oxcarbazepine (OXC). The percentage of methanol (MeOH) in the mobile phase containing acetonitrile (ACN) as the main solvent was found to significantly influence analyte retention and resolution. A reversal of elution order of OXC and (R)-licarbazepine was observed, depending on the MeOH percentage in the mobile phase. The optimized mobile phase consisted of ACN/MeOH/acetic acid/diethylamine (95/5/0.2/0.07; v/v/v/v). The potential of this chemo- and enantioselective LC method combined with solid-phase extraction (SPE) was then evaluated for in vitro metabolism studies using ESL as a model case. Only eslicarbazepine could be detected after incubation of ESL in human liver microsome systems. [less ▲]

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See detailReply to "a model lacking relevant literature comparison".
Wang, T.; Feng, Y.; Zhao, X. et al

in Journal of Pharmaceutical & Biomedical Analysis (2015), 104

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See detailSeparation of human, bovine, and porcine insulins, three very closely related proteins, by micellar electrokinetic chromatography.
Lamalle, Caroline ULg; Roland, Diane ULg; Crommen, Jacques ULg et al

in Electrophoresis (2015), 36(19), 2504-6

Human, bovine, and porcine insulins are small proteins with very closely related amino acid sequences, which makes their separation challenging. In this study, we took advantage of the high-resolution ... [more ▼]

Human, bovine, and porcine insulins are small proteins with very closely related amino acid sequences, which makes their separation challenging. In this study, we took advantage of the high-resolution power of CE, and more particularly of micellar electrokinetic chromatography, to separate those biomolecules. Among several surfactants, perfluorooctanoic acid ammonium salt was selected. Then, using a design of experiments approach, the optimal BGE composition was found to consist of 50 mM ammonium acetate pH 9.0, 65 mM perfluorooctanoic acid ammonium salt, and 4% MeOH. The three insulins could be separated within 12 min with a satisfactory resolution. This method could be useful to detect possible counterfeit pharmaceutical formulations. Indeed, it would be easy to determine if human insulin was replaced by bovine or porcine insulin. [less ▲]

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See detailComparative evaluation of a one-pot strategy for the preparation of beta-cyclodextrin-functionalized monoliths: Effect of the degree of amino substitution of beta-cyclodextrin on the column performance.
Zhang, Qiaoxuan; Guo, Jialiang; Xiao, Yuan et al

in Journal of separation science (2015), 38(11), 1813-21

To further evaluate the feasibility and applicability of the one-pot strategy in monolithic column preparation, two novel beta-cyclodextrin-functionalized organic polymeric monoliths were prepared using ... [more ▼]

To further evaluate the feasibility and applicability of the one-pot strategy in monolithic column preparation, two novel beta-cyclodextrin-functionalized organic polymeric monoliths were prepared using two beta-cyclodextrin derivatives, i.e. mono(6-amino-6-deoxy)-beta-cyclodextrin and heptakis(6-amino-6-deoxy)-beta-cyclodextrin. In this improved method, mono(6-amino-6-deoxy)-beta-cyclodextrin or heptakis(6-amino-6-deoxy)-beta-cyclodextrin reacted with glycidyl methacrylate to generate the corresponding functional monomers and were subsequently copolymerized with ethylene dimethacrylate. The polymerization conditions for both monoliths were carefully optimized to obtain satisfactory column performance with respect to column efficiency, reproducibility, permeability, and stability. The obtained poly(glycidyl methacrylate-mono(6-amino-6-deoxy)-beta-cyclodextrin-co-ethylene dimethacrylate) and poly(glycidyl methacrylate-heptakis(6-amino-6-deoxy)-beta-cyclodextrin-co-ethylene dimethacrylate) monoliths exhibited a uniform structure, good permeability, and mechanical stability as indicated by scanning electron microscopy and micro-high-performance liquid chromatography experimental results. Because of the probable existence of multi-glycidyl methacrylate linking spacers on the poly(glycidyl methacrylate-heptakis(6-amino-6-deoxy)-beta-cyclodextrin-co-ethylene dimethacrylate) monolith, the effect of the ratio of glycidyl methacrylate/heptakis(6-amino-6-deoxy)-beta-cyclodextrin was especially studied, and satisfactory reproducibility could still be achieved by strictly controlling the composition of the polymerization mixture. To investigate the effect of the degree of amino substitution of beta-cyclodextrin on column performance, a detailed comparison of the two monoliths was also carried out using series of analytes including small peptides and chiral acids. It was found that the beta-cyclodextrin-functionalized monolith with mono-glycidyl methacrylate linking spacers demonstrated better chiral separation performance than that with multi-glycidyl methacrylate linking spacers. [less ▲]

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See detailOne-pot preparation of a sulfamethoxazole functionalized affinity monolithic column for selective isolation and purification of trypsin.
Xiao, Yuan; Guo, Jialiang; Ran, Danni et al

in Journal of chromatography. A (2015), 1400

A facile and efficient "one-pot" copolymerization strategy was used for the preparation of sulfonamide drug (SA) functionalized monolithic columns. Two novel SA-immobilized methacrylate monolithic columns ... [more ▼]

A facile and efficient "one-pot" copolymerization strategy was used for the preparation of sulfonamide drug (SA) functionalized monolithic columns. Two novel SA-immobilized methacrylate monolithic columns, i.e. poly(GMA-SMX-co-EDMA) and poly(GMA-SAA-co-EDMA) were prepared by one-pot in situ copolymerization of the drug ligand (sulfamethoxazole (SMX) or sulfanilamide (SAA)), the monomer (glycidyl methacrylate, GMA) and the cross-linker (ethylene dimethacrylate, EDMA) within 100 mum i.d. capillaries under optimized polymerization conditions. The physicochemical properties and column performance of the fabricated monolithic columns were characterized by elemental analysis, scanning electron microscopy and micro-HPLC. Satisfactory column permeability, efficiency and separation performance were obtained on the optimized poly(GMA-SMX-co-EDMA) monolithic column for small molecules, such as a standard test mixture and eight aromatic ketones. Notably, it was found that the poly(GMA-SMX-co-EDMA) monolith showed a selective affinity to trypsin, while the poly(GMA-SAA-co-EDMA) monolith containing sulfanilamide did not exhibit such affinity at all. This research not only provides a novel monolith for the selective isolation and purification of trypsin, but it also offers the possibility to easily prepare novel drug functionalized methacrylate monoliths through a one-pot copolymerization strategy. [less ▲]

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See detailSeparation of N-derivatized di- and tri-peptide stereoisomers by micro-liquid chromatography using a quinidine-based monolithic column - Analysis of l-carnosine in dietary supplements.
Wang, Qiqin; Sanchez-Lopez, Elena; Han, Hai et al

in Journal of chromatography. A (2015)

In the present study, a new analytical methodology was developed enabling the enantiomeric determination of N-derivatized di- and tri-peptides in dietary supplements using chiral micro-LC on a monolithic ... [more ▼]

In the present study, a new analytical methodology was developed enabling the enantiomeric determination of N-derivatized di- and tri-peptides in dietary supplements using chiral micro-LC on a monolithic column consisting of poly(O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine-co-2-hydroxy ethyl methacrylate-co-ethylene dimethacrylate) (poly(MQD-co-HEMA-co-EDMA)). After optimization of the mobile phase conditions, a baseline resolution of the stereoisomers of 24 out of 53 N-derivatized di- and tri-peptides was obtained. 3,5-Dinitrobenzoyl- and 3,5-dichlorobenzoyl-peptide stereoisomers were separated with exceptionally high selectivity and resolution. The monolithic column was then applied to the quantitative analysis of l-carnosine and its enantiomeric impurity in three different commercial dietary supplements. Method validation demonstrated satisfactory results in terms of linearity, precision, selectivity, accuracy and limits of detection and quantification. The determined amounts of l-carnosine in commercial formulations were in agreement with the labeled content for all analyzed samples, and the enantiomeric impurity was found to be below the limit of detection (LOD), showing the potential of the poly(MQD-co-HEMA-co-EDMA) monolithic column as a reliable tool for the quality control of l-carnosine in dietary supplements by micro-LC. [less ▲]

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See detailComparative enantiomer affinity pattern of beta-blockers in aqueous and nonaqueous CE using single-component anionic cyclodextrins.
Feng, Ying; Wang, Tingting; Jiang, Zhengjin et al

in Electrophoresis (2015), 36(11-12), 1358-64

A series of eight chiral beta-blocker drugs, acebutolol, atenolol, carazolol, carteolol, carvedilol, propranolol, sotalol, and talinolol, have been enantioseparated using two single-component anionic beta ... [more ▼]

A series of eight chiral beta-blocker drugs, acebutolol, atenolol, carazolol, carteolol, carvedilol, propranolol, sotalol, and talinolol, have been enantioseparated using two single-component anionic beta-CD derivatives, namely heptakis (2,3-di-O-methyl-6-sulfo)-beta-CD (HDMS-beta-CD) and heptakis (2,3-di-O-acetyl-6-sulfo)-beta-CD (HDAS-beta-CD), in aqueous CE and NACE. The influence of the nature of substituents (methyl or acetyl) in positions 2 and 3 on the CD derivatives and of the electrophoretic medium (water or methanol) on the enantioselectivity and enantiomer affinity pattern (EAP) of these structurally related compounds was systematically studied. All eight beta-blockers could be enantioseparated at least partially in the four CE systems, except sotalol with HDMS-beta-CD in NACE. In general, lower affinity and enantioselectivity were obtained in the presence of HDMS-beta-CD compared to HDAS-beta-CD. Reversals of EAPs were observed for all compounds. EAPs toward these two CDs were found to be opposite to each other in NACE for all compounds except carvedilol and in aqueous CE for atenolol, carteolol, talinolol, and sotalol. It is particularly noteworthy that opposite EAPs were also observed using the same CD derivative when the aqueous BGE was replaced with the methanolic one: for carazolol, carvedilol, and propranolol in the presence of HDMS-beta-CD and for acebutolol and carvedilol with HDAS-beta-CD. [less ▲]

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See detailPreparation and evaluation of novel zwitterionic HILIC monolithic columns
Liu, C; Li, H; Crommen, Jacques ULg et al

Conference (2015)

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See detailSimultaneous determination of insulin and its analogues in pharmaceutical formulations by micellar electrokinetic chromatography
Lamalle, Caroline ULg; Servais, Anne-Catherine ULg; RADERMECKER, Régis ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2015)

A simple and efficient MEKC method was developed to simultaneously determine human insulin, its five analogues, the main degradation products and the excipients usually present in injection formulations ... [more ▼]

A simple and efficient MEKC method was developed to simultaneously determine human insulin, its five analogues, the main degradation products and the excipients usually present in injection formulations. A very fast method with a total analysis time of 3 min was then successfully validated for the analysis of human insulin and the quality control of different commercial formulations was carried out. [less ▲]

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See detailDéveloppement de méthodes séparatives pour détecter la contrefaçon de molécules biosynthétiques comme l'insuline et les GHRP
Lamalle, Caroline ULg; Baptiste, Emeline; Marini Djang'Eing'A, Roland ULg et al

in Spectra Analyse (2014), 43

Counterfeiting is a widespread problem in the world. The medicines, like insulin or GHRP, need a strict quality control. Capillary electrophoresis and liquid chromatography methods were developed to ... [more ▼]

Counterfeiting is a widespread problem in the world. The medicines, like insulin or GHRP, need a strict quality control. Capillary electrophoresis and liquid chromatography methods were developed to analyze these peptides. The human insulin and its different analogues (lispro, aspart, glulisin, glargin and detemir) were separated by MEKC within 15 minutes. The GHRP-2 and -6 were separated by HPLC also in 15 minutes. Several samples of GHRP-6 were analyzed and non-compliances were reported. These analytical approaches seem to be promising to fight against the counterfeiting of such medicines. [less ▲]

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See detailStratégies analytiques pour la détection de contrefaçons de médicaments pour la dysfonction érectile
Sacre, Pierre-Yves ULg; Deconinck, Eric; Marini Djang'Eing'A, Roland ULg et al

in Spectra Analyse (2014), 43

Erectile dysfunction drugs are among the most counterfeit drug classes in industrialized countries. To fight against this plague, several analytical approaches are available for control laboratories. The ... [more ▼]

Erectile dysfunction drugs are among the most counterfeit drug classes in industrialized countries. To fight against this plague, several analytical approaches are available for control laboratories. The present article reviews the main used techniques and concludes presenting a general strategy for the detection and handling of drug counterfeits. [less ▲]

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See detailIn-capillary derivatization with (-)-1-(9-fluorenyl)ethyl chloroformate as chiral labeling agent for the electrophoretic separation of amino acids.
Fradi, Ines ULg; Farcas, Elena ULg; Said, Azza Ben et al

in Journal of chromatography. A (2014), 1363

An original micellar electrokinetic chromatography (MEKC) method using in-capillary derivatization with a chiral labeling reagent was developed for the separation of amino acid (AA) derivatives. The ... [more ▼]

An original micellar electrokinetic chromatography (MEKC) method using in-capillary derivatization with a chiral labeling reagent was developed for the separation of amino acid (AA) derivatives. The potential of (-)-1-(9-fluorenyl)-ethyl chloroformate (FLEC) as in-capillary derivatization agent is described for the first time. Several parameters for in-capillary derivatization and subsequent MEKC separation were systematically investigated using experimental designs. Firstly experimental conditions for in-capillary derivatization were optimized using face-centered central composite design (FCCD). Mixing voltage and time as well as concentration of the labeling solution were investigated. Efficient labeling was achieved by sequential injection of AAs and FLEC labeling solution followed by the application of a voltage of 0.2kV for 570s. The background electrolyte (BGE) composition was then optimized in order to achieve selectivity. A FCCD was performed with two factors, namely the sodium dodecyl sulfate (SDS) concentration and the percentage of propan-2-ol (IPA). The separation of 12 pairs of derivatized AA (FLEC-AA) diastereomers was achieved with resolution values comprised between 3 and 20. Furthermore, an efficient derivatization and separation of 29 FLEC-AA derivatives were achieved in a single run using a buffer made up of 40mM sodium tetraborate, 21mM SDS and 8.5% IPA. The method was successfully applied to the analysis of spiked artificial cerebrospinal fluid (aCSF) sample. [less ▲]

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See detailLiposome electrokinetic chromatography based in vitro model for early screening of the drug-induced phospholipidosis risk.
Wang, Tingting; Feng, Ying; Jin, Xiaohan et al

in Journal of Pharmaceutical & Biomedical Analysis (2014), 96

Drug-induced phospholipidosis (PLD) is a storage disorder of lysosomes characterized by the excessive accumulation of phospholipids as a result of improper medical treatments. Although few evidences have ... [more ▼]

Drug-induced phospholipidosis (PLD) is a storage disorder of lysosomes characterized by the excessive accumulation of phospholipids as a result of improper medical treatments. Although few evidences have supported that PLD can induce significant pathological consequences, this potential toxicity indeed can put off the drug discovery process. In this research, a high-throughput liposome electrokinetic chromatography (LEKC) method was validated to evaluate the PLD risk of drug candidates by screening drug-phospholipid interaction, which correlates to the phospholipidosis inducing risk. A statistical analysis based on the Spearman's correlation test showed that the retention factors (log k) of the tested drugs in the LEKC system and the literature reported in vivo and in vitro PLD data were highly correlated. In order to investigate the predictability of LEKC, the effect of liposome composition such as the molar ratio of phospholipids and the addition of cholesterol were also discussed in this study. The results indicated that the LEKC method could offer a fast, reliable and cost-effective screening tool for early prediction of the PLD inducing potential of drug candidates. [less ▲]

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