References of "Fillet, Marianne"
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See detailDesigned combination of chiral selectors for adjustment of enantioseparation selectivity in capillary electrophoresis.
Fillet, Marianne ULg; Chankvetadze, Bezhan; Crommen, Jacques ULg et al

in Electrophoresis (1999), 20(13), 2691-7

In this study an attempt has been made to explain the reasons for changing the enantioseparation selectivity in some dual cyclodextrin (CD) systems compared to the use of single chiral selectors in ... [more ▼]

In this study an attempt has been made to explain the reasons for changing the enantioseparation selectivity in some dual cyclodextrin (CD) systems compared to the use of single chiral selectors in capillary electrophoresis (CE). An explanation for selectivity changes is proposed based on the effect of the chiral selector on the mobility of the analyte. In order to support the proposed mechanism, several dual systems were designed on the basis of the known recognition pattern of enantiomers for individual CDs. In most cases the separation selectivity could be adjusted in a designed way. There was no experimental evidence for simultaneous binding of a given chiral analyte with both chiral selectors or of chiral recognition of an analyte complex with one CD by another CD. [less ▲]

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See detailMethod Development Strategies for the Enantioseparation of Drugs by Capillary Electrophoresis Using Cyclodextrins as Chiral Additives
Fillet, Marianne ULg; Hubert, Philippe ULg; Crommen, Jacques ULg

in Electrophoresis (1998), 19(16-17), 2834-40

General strategies for the development of capillary electrophoretic methods for the enantiomeric separation of basic, acidic or neutral drugs were developed. For all kinds of compounds, the use of a ... [more ▼]

General strategies for the development of capillary electrophoretic methods for the enantiomeric separation of basic, acidic or neutral drugs were developed. For all kinds of compounds, the use of a buffer made of 100 mM phosphoric acid adjusted to pH 3 with triethanolamine and containing anionic and/or uncharged cyclodextrin (CD) derivatives as chiral selectors was recommended. Two different optimization schemes depending on the acidic or basic character of the analytes, were elaborated. For most basic compounds present in cationic form at pH 3, enantiomeric separation could be achieved in the normal polarity mode. Different beta-cyclodextrin derivatives were first tested at a given concentration. Five derivatives were found to be particularly useful for enantioseparations in capillary electrophoresis (CE): the anionic carboxymethyl-beta-CD (CMCD) and sulfobutyl-beta-CD (SBCD) and the neutral dimethyl-beta-CD (DMCD), trimethyl-beta-CD (TMCD) and hydroxypropyl-beta-CD (HPCD). After selection of the most suitable CD, its concentration was optimized with respect to chiral resolution. If necessary, a further improvement in resolution could often be obtained for the enantiomers of cationic solutes by increasing the buffer pH from 3 to 5 using CMCD as chiral additive. Another possible alternative for enhancement in chiral resolution was the addition of metharlol or cyclohexanol to the buffer. For acidic drugs, essentially present in uncharged form at pH 3, and for neutral solutes, anionic CD derivatives such as SBCD or CMCD were first tested at a given concentration in the reversed polarity mode. Dual systems, based on the simultaneous addition of a charged CD (SBCD or CMCD) and a neutral CD (TMCD or DMCD), could then be investigated for resolution improvement. After optimization of the CD concentrations, the use of dual systems with CMCD at pH 5 could also be tested if necessary, especially for very weak acidic and neutral drugs. By applying these optimization strategies, 48 of the 50 drugs examined as model compounds could be fully enantioseparated by CE in short analysis times (usually less than 10 min). [less ▲]

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See detailDevelopment of a non-surfactant parenteral formulation of miconazole by the use of cyclodextrins
Piel, Géraldine ULg; Evrard, Brigitte ULg; Fillet, Marianne ULg et al

in International Journal of Pharmaceutics (1998), 169

Miconazole is an antimycotic drug exhibiting a very poor water solubility (B1.03 mg:ml). It has been shown that cyclodextrins (CDs) are able to form inclusion complexes with miconazole and that they are ... [more ▼]

Miconazole is an antimycotic drug exhibiting a very poor water solubility (B1.03 mg:ml). It has been shown that cyclodextrins (CDs) are able to form inclusion complexes with miconazole and that they are able to increase its aqueous solubility. Miconazole is a weak base whose solubility depends of the pH. The purpose of this study was to investigate the influence of both CDs and different acids on the solubility of miconazole. It was found that a synergistic effect existed between CDs and different acids. The combination of hydroxypropyl-bCD (HP-bCD) (100 mM) or sulfobutylether 7-bCD (SBE7-bCD) (50 mM) and lactic acid (50 mM) allowed to dissolve more than 10 mg of miconazole per ml. NMR studies confirmed the formation of an inclusion complex miconazole–CD in an acidic medium. It was also shown by the NMR studies that the complex formed was a 1:1 complex. These results demonstrate that it is possible to develop a parenteral aqueous solution of miconazole without surfactant. [less ▲]

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See detailMethod development strategies for the rapid enantioseparation of drugs by capillary electrophoresis using cyclodextrins as chiral additives
Fillet, Marianne ULg; Fotsing, L.; Piette, V. et al

in Journal de Pharmacie de Belgique (1998), 53

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See detailQuantitative analysis of folic acid in a pharmaceutical formulation by capillary electrophoresis
Fotsing, L.; Fillet, Marianne ULg; Hubert, Philippe ULg et al

in Journal de Pharmacie de Belgique (1998), 53

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See detailStereoselective determination of s-naproxen in tablets by capillary electrophoresis
Fillet, Marianne ULg; Fotsing, L.; Hubert, Philippe ULg et al

in Journal de Pharmacie de Belgique (1998), 53

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See detailEnantioseparation of Acidic Drugs by Capillary Electrophoresis Using Dual Systems with Mixtures of Charged and Neutral Cyclodextrins
Fillet, Marianne ULg; Fotsing, Lucas ULg; Schomburg, G. et al

in Biomedical Chromatography : BMC (1998), 12(3, May-Jun), 131-2

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See detailStereoselective determination of S-naproxen in tablets by capillary electrophoresis.
Fillet, Marianne ULg; Fotsing, Lucas; Bonnard, J. et al

in Journal of Pharmaceutical & Biomedical Analysis (1998), 18(4-5), 799-805

A capillary electrophoresis (CE) method was developed for the stereoselective determination of the non-steroidal anti-inflammatory drug (NSAID), S-naproxen, in tablets. Several beta-cyclodextrin ... [more ▼]

A capillary electrophoresis (CE) method was developed for the stereoselective determination of the non-steroidal anti-inflammatory drug (NSAID), S-naproxen, in tablets. Several beta-cyclodextrin derivatives (CDs) were tested as chiral selectors, including sulfobutyl-beta-CD (SBCD), carboxymethyl-beta-CD (CMCD), dimethyl-beta-CD (DMCD) and trimethyl-beta-CD (TMCD), in a phosphoric acid/triethanolamine pH 3 buffer. Under these conditions, the analyte was mainly present in an uncharged form and therefore, the use a neutral CD (DMCD or TMCD) alone could not lead to enantiomeric separation. On the contrary, by addition of a charged CD (SBCD or CMCD) to the running buffer, giving the analyte enantiomers an adequate mobility, chiral resolution could be achieved, although the resolution values obtained in this case were not quite satisfactory (Rs < 1.5). Dual systems, based on the use of mixtures of charged and neutral CDs, were then investigated. The SBCD/TMCD system was found to be particularly well suited to the enantioseparation of naproxen and after optimisation of the concentrations of both CDs, a resolution value of 5.4 could be obtained. The method was validated for the determination of R-naproxen (enantiomeric impurity) in the 0.1-2% range, using the racemic mixture of the analyte. A second validation was performed in the 50-150% range for the quantitation of S-naproxen. In both cases, good results with respect to linearity, precision and accuracy were obtained. [less ▲]

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See detailDetermination of Six Water-Soluble Vitamins in a Pharmaceutical Formulation by Capillary Electrophoresis
Fotsing, Lucas ULg; Fillet, Marianne ULg; Bechet, I. et al

in Journal of Pharmaceutical & Biomedical Analysis (1997), 15(8), 1113-23

A method was developed for the quantitative analysis of six water-soluble vitamins (thiamine, nicotinamide, riboflavine, pyridoxine, ascorbic acid and pantothenic acid) in a pharmaceutical formulation ... [more ▼]

A method was developed for the quantitative analysis of six water-soluble vitamins (thiamine, nicotinamide, riboflavine, pyridoxine, ascorbic acid and pantothenic acid) in a pharmaceutical formulation, using free solution capillary zone electrophoresis (CZE) in uncoated fused silica capillaries and UV detection. The influence of different parameters, such as the nature of the buffer anionic component and buffer concentration on the CZE separation of vitamins was investigated using four vitamins of the B group as model compounds. A good compromise between resolution, analysis time and analyte stability was obtained by use of a 50 mM borax buffer of pH 8.5. This CZE method was found to be very useful for the separation of more complex samples, a mixture of ten water-soluble vitamins being completely resolved in about 10 min. However, cyanocobalamine could not be separated from nicotinamide in this CZE system, the two compounds being in uncharged form at the pH used. These two compounds could easily be resolved by micellar electrokinetic chromatography (MEKC), the anionic surfactant dodecylsulfate being added to the running buffer at 25 mM concentration. In the pharmaceutical formulation, some excipients were found to be adsorbed to the capillary surface, giving rise to a progressive decrease of the electroosmotic flow and consequently to a simultaneous increase of analyte migration times. A capillary wash with sodium hydroxide had to be made between successive runs in order to minimize these effects. Good results with respect to linearity, precision and accuracy were obtained in the concentration range studied for the six vitamins, using nicotinic acid as internal standard. [less ▲]

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