References of "Servais, Anne-Catherine"
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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 detailMicellar electrokinetic chromatography against the counterfeiting of insulin formulations
Lamalle, Caroline ULg; Servais, Anne-Catherine ULg; Crommen, Jacques ULg et al

Poster (2014)

Insulin plays an important role in the homeostasis of blood glucose concentration. A deficiency of this hormone causes diabetes, which can be treated by subcutaneous injection of synthetic insulin ... [more ▼]

Insulin plays an important role in the homeostasis of blood glucose concentration. A deficiency of this hormone causes diabetes, which can be treated by subcutaneous injection of synthetic insulin. Besides human regular insulin, several modified analogues have been developed to accelerate (Lispro, Aspart, Glulisin) or delay (Glargin, Detemir) its absorption. Moreover, protamine is sometimes associated with human, Lispro or Aspart insulin to give a crystalline form, which delays the action of insulin, providing it with a prolonged absorption profile after injection. Diabetes is one of the most common metabolic diseases in the world; its prevalence increases continuously. A lot of patients are therefore concerned with the treatment, which is relatively expensive and requires a prescription. Some pharmaceutical formulations can sometimes be found without prescription on the parallel market but the risk of drug counterfeiting is then considerably increased. The poor quality of these drugs can lead to harmful consequences for the public health. It is therefore essential to develop a suitable method for the identification and quantification of human insulin and its analogues inside formulations. Ortner et al. [1] have already proposed micellar electrokinetic chromatography (MEKC) methods to detect simultaneously human insulin and its five analogues but no quantitative applications were presented. Furthermore, formulations containing protamine were not tested so we included them in our study. The first optimisation step involved the sample preparation procedure. An acidic sample solution (10 mM HCl) was finally selected to solubilise protamine and Glargin. Then the background electrolyte composition was investigated to separate the components present in the formulations. A basic buffer (50 mM ammonium acetate pH 9) was selected, providing an important and stable electroosmotic flow, a negative charge to the insulins and avoiding any adsorption to the capillary wall. The addition of sodium dodecylsulfate (SDS) and acetonitrile (ACN) was also found crucial for selectivity. With 50 mM SDS and 15% ACN the six insulins and the two major excipients (phenol and meta-cresol) were fully separated within 15 minutes. This method was then entirely validated for the human insulin and the quality control of related formulations was performed. The next step will be the validation and the quantification of the other analogues. [less ▲]

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See detailDevelopment and validation of a liquid chromatographic method for the stability study of a pharmaceutical formulation containing voriconazole using cellulose tris(4-chloro-3-methylphenylcarbamate) as chiral selector and polar organic mobile phases.
Servais, Anne-Catherine ULg; Moldovan, Radu-Cristian ULg; Farcas, Elena ULg et al

in Journal of chromatography. A (2014), 1363

The ophthalmic solution of voriconazole, i.e. (2R,3S)-2-(2,4-difluorophenyl)-3-(5-fluoropyrimidin-4-yl)-1-(1H-1,2,4-triazol-1-y l)butan-2-ol, made from an injection formulation which also contains ... [more ▼]

The ophthalmic solution of voriconazole, i.e. (2R,3S)-2-(2,4-difluorophenyl)-3-(5-fluoropyrimidin-4-yl)-1-(1H-1,2,4-triazol-1-y l)butan-2-ol, made from an injection formulation which also contains sulfobutylether-beta-cyclodextrin sodium salt as an excipient (Vfend((R))), is used for the treatment of fungal keratitis. A liquid chromatographic (LC) method using polar organic mobile phase and cellulose tris(4-chloro-3-methylphenylcarbamate) coated on silica as chiral stationary phase was successfully developed to evaluate the chiral stability of the ophthalmic solution. The percentage of methanol (MeOH) in the mobile phase containing acetonitrile (ACN) as the main solvent significantly influenced the retention and resolution of voriconazole and its enantiomer ((2S,3R)-2-(2,4-difluorophenyl)-3-(5-fluoropyrimidin-4-yl)-1-(1H-1,2,4-triazol-1- yl)butan-2-ol). The optimized mobile phase consisted of ACN/MeOH/diethylamine/trifluoroacetic acid (80/20/0.1/0.1; v/v/v/v). The method was found to be selective not only regarding the enantiomer of voriconazole but also regarding the specified impurities described in the monograph from the European Pharmacopoeia. The LC method was then fully validated applying the strategy based on total measurement error and accuracy profiles. Under the selected conditions, the determination of 0.1% of voriconazole enantiomer could be performed. Finally, a stability study of the ophthalmic solution was conducted using the validated LC method. [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 detailEVALUATION OF α-SYNUCLEIN AS BIOMARKER OF PARKINSON'S DISEASE
Napp, Aurore ULg; Garraux, Gaëtan ULg; Servais, Anne-Catherine ULg et al

Conference (2013, October 17)

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See detailL’électrophorèse capillaire micellaire pour la détermination simultanée de l’insuline et de ses analogues dans des formulations pharmaceutiques
Lamalle, Caroline ULg; Servais, Anne-Catherine ULg; Crommen, Jacques ULg et al

Poster (2013, June)

L’insuline joue un rôle important dans l’homéostasie de la concentration sanguine en glucose. Un déficit de cette hormone cause le diabète (de type I) qui peut être traité par injection sous-cutanée ... [more ▼]

L’insuline joue un rôle important dans l’homéostasie de la concentration sanguine en glucose. Un déficit de cette hormone cause le diabète (de type I) qui peut être traité par injection sous-cutanée d’insuline synthétique. En plus de l’insuline humaine, plusieurs analogues ont été développés pour accélérer son absorption (Lispro, Aspart, Glulisin) ou la retarder (Glargin, Detemir). La protamine est également parfois utilisée avec l’insuline humaine, Lispro ou Aspart pour former un complexe et augmenter la durée d’action. Le diabète est une des maladies métaboliques les plus courantes dans le monde; la prévalence ne cesse de s’élever. Beaucoup de patients sont donc concernés par le traitement qui est relativement cher et nécessite une ordonnance. Certaines formulations pharmaceutiques peuvent être trouvées sans ordonnance sur le marché parallèle mais la possibilité de contrefaçon existe. Et la mauvaise qualité de ces médicaments peut entrainer des conséquences néfastes pour la santé publique. Il est donc essentiel de développer une méthode permettant l’identification et la quantification de l’insuline humaine et de ses analogues. Ortner et al. [1] ont déjà proposé une méthode par électrophorèse capillaire micellaire (MEKC) pour séparer simultanément l’insuline humaine et ses 5 analogues, mais ils n’analysaient pas les formulations à base de protamine. Le nombre de ces formulations n’étant pas négligeable, nous les avons incluses dans notre étude. La première étape d’optimisation a été la préparation de l’échantillon. Une solution acide (0.01M d’HCl) a finalement été choisie pour solubiliser la protamine et la Glargine. Ensuite, la composition du background electrolyte a été investiguée pour séparer les composants des formulations. Un tampon basique (50mM d’acétate d’ammonium à pH 9) a été choisi, engendrant un flux électroosmotique important et stable, une charge négative à l’insuline et empêchant l’adsorption à la paroi du capillaire. L’addition de dodécyl sulfate de sodium et d’acétonitrile s’est ensuite révélée déterminante pour la sélectivité. Les 6 insulines et les 2 excipients majeurs (le phénol et le m-crésol) ont été complètement séparés endéans 15 minutes. La méthode précitée a ensuite été adaptée pour permettre la séparation de chaque insuline et de ses produits de dégradation. [less ▲]

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See detailDéveloppement de méthodes de quantification en milieu complexe par chromatographie liquide microfluidique couplée à la spectrometrie de masse
Houbart, Virginie ULg; Rozet, Eric ULg; Crommen, Jacques ULg et al

Conference (2013, June)

L’hepcidine est un biomarqueur peptidique dont l’intérêt tant comme outil de diagnostic que de suivi de pathologies est de plus en plus solidement établi. Il existe donc une demande forte d’outils ... [more ▼]

L’hepcidine est un biomarqueur peptidique dont l’intérêt tant comme outil de diagnostic que de suivi de pathologies est de plus en plus solidement établi. Il existe donc une demande forte d’outils sensibles et robustes afin de la doser au sein de milieux biologiques tels que le plasma ou le sérum. Une méthode analytique a été développée à l’aide d’un système chromatographique miniaturisé (nanoLC-chip) couplé à un spectromètre de masse permettant d’assurer un dosage de l’hepcidine à la fois sensible et fiable. Lors du développement de cette méthode, il a été constaté que la composition de l’échantillon avait une influence majeure sur la réponse analytique. Or, l’utilisation de systèmes chromatographiques miniaturisés implique souvent l’injection de volumes proportionnellement très importants par rapport aux dimensions du système, ce qui amplifie encore l’impact de sa composition. C’est pourquoi il est capital d’avoir une bonne compréhension des phénomènes qui ont lieu entre l’injection de l’échantillon dans le système chromatographique et la détection par spectrométrie de masse, et particulièrement lors du développement de méthodes analytiques quantitatives. Dans cette étude, nous avons utilisé la planification expérimentale afin de mieux comprendre le comportement chromatographique des peptides, ainsi que les facteurs qui influencent la sensibilité de la méthode développée. Un mélange de peptides a été sélectionné, varié tant du point de vue du poids moléculaire que du point isoélectrique et de l’hydropathie. Un plan de criblage a permis de délimiter le domaine expérimental ainsi que les facteurs significatifs parmi la composition de la phase mobile (proportion et nature de l’agent de paire d’ions) et de l’échantillon en lui-même (nature de l’agent de paire d’ions et proportion de solvant organique). Ensuite, un plan d’expériences factoriel complet a été mis en œuvre afin d’observer plus finement le rôle de chaque facteur ainsi que les interactions éventuelles qui les lient. Certains facteurs ont montré un effet très marqué tant sur l’intensité de la réponse que sur la rétention. Entre autres, la composition de l’échantillon, facteur parfois négligé lors du développement de méthodes, a démontré son importance capitale, en particulier sur les phénomènes de rétention des peptides. Les données obtenues ont également permis de dégager des conditions optimales d’analyse en termes de rétention et de sensibilité. Enfin, une analyse en composantes principales a également été réalisée sur le grand nombre de données récoltées dans le but de mettre en évidence d’éventuels propriétés physicochimiques des peptides qui pourraient avoir un impact significatif sur les réponses étudiées. [less ▲]

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See detailUnusual Amino Acids and Monofluoroacetate from Dichapetalum michelsonii (Umutambasha), a Toxic Plant from Rwanda
Esters, Virginie ULg; Karangwa, Charles; Tits, Monique ULg et al

in Planta Medica (2013), 79

In the course of our investigations on Umutambasha in order to identify its convulsant principles, small quantities of monofluoroacetate were observed in stem bark, leaves, and fruits of this plant newly ... [more ▼]

In the course of our investigations on Umutambasha in order to identify its convulsant principles, small quantities of monofluoroacetate were observed in stem bark, leaves, and fruits of this plant newly identified as Dichapetalum michelsonii Hauman. Conclusive evidence for a monofluoroacetate presence came from its isolation from the freeze-dried extract of stem bark. Three free unusual amino acids, named N-methyl-α-alanine, N-methyl-β-alanine, and 2,7-diaminooctan-1,8-dioic acid, described for the first time in a plant, and known trigonelline were also isolated from the stem bark of D. michelsonii. Structure elucidations were mainly achieved by spectroscopic methods (1H-NMR, 2D-NMR, MS) and by comparison with authentic references. These unusual amino acids were detected by a fast, reliable TLC analysis in all our batches of Umutambasha, suggesting that they could be used for identification purposes in case of human or livestock intoxications. Finally, EEG recordings and behavioural observations performed in mice suggested that the convulsive patterns produced by Umutambasha are the consequence of monofluoroacetate presence in D. michelsonii. [less ▲]

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See detailSimultaneous determination of insulin and its analogues in pharmaceutical formulations by micellar electrokinetic chromatography (MEKC)
Lamalle, Caroline ULg; Servais, Anne-Catherine ULg; Crommen, Jacques ULg et al

Poster (2013)

Insulin plays an important role in the homeostasis of blood glucose concentration. A deficiency of this hormone causes diabetes, which can be treated by subcutaneous injection of synthetic insulin ... [more ▼]

Insulin plays an important role in the homeostasis of blood glucose concentration. A deficiency of this hormone causes diabetes, which can be treated by subcutaneous injection of synthetic insulin. Besides human regular insulin, several modified analogues have been developed to accelerate (Lispro, Aspart, Glulisin) or delay (Glargin, Detemir) its absorption. Moreover, protamine is sometimes associated with human, Lispro or Aspart insulin to give a crystalline form, which delays the action of insulin, providing it with a prolonged absorption profile after injection. Diabetes is one of the most common metabolic diseases in the world; its prevalence increases continuously. A lot of patients are therefore concerned with the treatment, which is relatively expensive and requires a prescription. Some pharmaceutical formulations can sometimes be found without prescription on the parallel market but the risk of drug counterfeiting is then considerably increased. The poor quality of these drugs can lead to harmful consequences for the public health. It is therefore essential to develop a suitable method for the identification and quantification of human insulin and its analogues. Ortner et al. have already proposed micellar electrokinetic chromatography (MEKC) methods to analyse simultaneously human insulin and its five analogues but formulations containing protamine were not tested. Since the number of these formulations is significant, we included them in our study. The first optimisation step involved the sample preparation procedure. An acidic sample solution (0.01 M HCl) was finally selected to solubilise protamine and Glargin. Then the background electrolyte composition was investigated to separate the components present in the formulations. A basic buffer (50 mM ammonium acetate pH 9) was selected, providing an important and stable electroosmotic flow, a negative charge to insulin and related compounds and avoiding any adsorption to the capillary wall. The addition of sodium dodecyl sulfate and acetonitrile were also found crucial for selectivity. The six insulins and the two major excipients (phenol and m-cresol) were fully separated within 15 minutes The aforementioned method was then adapted to permit the separation of each insulin from its degradation products. [less ▲]

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See detailEnantioseparations in nonaqueous capillary electrophoresis using charged cyclodextrins.
Servais, Anne-Catherine ULg; Fillet, Marianne ULg

in Methods in Molecular Biology 970: Chiral Separations (2013)

The enantioseparation of acidic and basic compounds can be successfully achieved in nonaqueous capillary electrophoresis using single-isomer charged beta-cyclodextrin (beta-CD) derivatives of opposite ... [more ▼]

The enantioseparation of acidic and basic compounds can be successfully achieved in nonaqueous capillary electrophoresis using single-isomer charged beta-cyclodextrin (beta-CD) derivatives of opposite charge to that of the analytes. This chapter describes how to separate the enantiomers of three basic substances selected as model compounds, i.e., alprenolol, bupranolol, and terbutaline, using the negatively charged heptakis(2,3-di-O-acetyl-6-O-sulfo)-beta-CD. The enantiomers of three acidic drugs (tiaprofenic acid, suprofen, and flurbiprofen) are resolved using a monosubstituted amino beta-CD derivative, namely, 6-monodeoxy-6-mono(3-hydroxy)propylamino-beta-CD. [less ▲]

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