Simultaneous determination of nifedipine and its metabolite in human plasma by LC/MS/MS using APCI interface

Poster (1998)

Method development and validation for the individual quantitation of drug en-antiomers using liquid chromatography or capillary electrophoresis

Conference (1998)

Liquid chromatographic separation of pirlindole enantiomers using different types of chiral stationary phases

in Journal de Pharmacie de Belgique (1998), 53

Determination of the enantiomeric purity of pirlindole by liquid chromatography using a cellulose based chiral stationary phase

in Journal de Pharmacie de Belgique (1998), 53

Résolution préparative du pirlindol, journées franco-belges de pharmacochimie

in Journal de Pharmacie de Belgique (1998), 53

Automated Determination of Tramadol Enantiomers in Human Plasma Using Solid-Phase Extraction in Combination with Chiral Liquid Chromatography

in Journal of Chromatography. B : Biomedical Sciences and Applications (1997), 698(1-2), 161-70

A sensitive and automated method for the separation and individual determination of tramadol enantiomers in plasma has been developed using solid-phase extraction (SPE) on disposable extraction cartridges ... [more ▼]

A sensitive and automated method for the separation and individual determination of tramadol enantiomers in plasma has been developed using solid-phase extraction (SPE) on disposable extraction cartridges (DECs) in combination with chiral liquid chromatography (LC). The SPE operations were performed automatically by means of a sample processor equipped with a robotic arm (ASPEC system). The DEC filled with ethyl silica (50 mg) was first conditioned with methanol and phosphate buffer, pH 7.4. A 1.0-ml volume of plasma was then applied on the DEC. The washing step was performed with the same buffer. The analytes were eluted with 0.15 ml of methanol, and 0.35 ml of phosphate buffer, pH 6.0, containing sodium perchlorate (0.2 M) were added to the extract before injection into the LC system. The enantiomeric separation of tramadol was achieved using a Chiralcel OD-R column containing cellulose tris-(3,5-dimethylphenylcarbamate) as chiral stationary phase. The mobile phase was a mixture of phosphate buffer, pH 6.0, containing sodium perchlorate (0.2 M) and acetonitrile (75:25). The mobile-phase pH and the NaClO4 concentration were optimized with respect to enantiomeric resolution. The method developed was validated. Recoveries for both enantiomers of tramadol were about 100%. The method was found to be linear in the 2.5-150 ng/ml concentration range [r2=0.999 for (+)- and (-)-tramadol]. The repeatability and intermediate precision at a concentration of 50 ng/ml were 6.5 and 8.7% for (+)-tramadol and 6.1 and 7.6% for (-)-tramadol, respectively. [less ▲]

Enantioselective Determination of Oxprenolol in Human Plasma Using Dialysis Coupled on-Line to Reversed-Phase Chiral Liquid Chromatography

in Journal of Pharmaceutical & Biomedical Analysis (1997), 15(9-10), 1365-74

A fully automated method for the determination of the enantiomers of oxprenolol in human plasma was developed, involving dialysis through a cellulose acetate membrane, clean-up and enrichment of the ... [more ▼]

A fully automated method for the determination of the enantiomers of oxprenolol in human plasma was developed, involving dialysis through a cellulose acetate membrane, clean-up and enrichment of the dialysate on a short precolumn and subsequent chiral liquid chromatographic (LC) analysis. All sample handling operations were executed automatically by a sample processor equipped with a robotic arm (ASTED system). The trace enrichment column (TEC) was packed with octadecylsilica. After conditioning of the TEC with the LC mobile phase and pH 3.0 acetate buffer. After the enrichment step, the analyte was transferred by the LC mobile phase to the analytical column by means of a switching valve. The influence of different parameters of the dialysis process on the recovery of oxprenolol was first investigated using achiral LC conditions. The volume as well as the aspirating and dispensing flow rates of the acceptor solution were the main parameters studied. Oxprenolol was separated on a C18 stationary phase used for the enantioseparation of oxprenolol was a Chiralcel OD-R column which contained cellulose tris (3,5-dimethylphenylcarbamate) coated on silica as chiral selector. The corresponding mobile phase consisted of a mixture of pH 6.0 phosphate buffer containing NaClO4 at 0.45 M concentration and acetonitrile (70:30 v/v). UV detection was performed at 273 nm. The method developed was validated. Recoveries for each enantiomer of oxprenolol were about 80%. The method was found to be linear in the 50-2500 ng ml-1 concentration range (r2 = 0.999 for both enantiomers) and good results with respect to intra- and inter-day reproducibility as well as accuracy were obtained. [less ▲]

Determination of N-acetylcysteine and its potential degradation products by LC/APCI+/MS/MS

Conference (1997)

Enantiomeric resolution of drugs by capillary electrophoresis

Conference (1997)

Enantiomeric separation of pirlindole enantiomers and dehydroprilindole by chrial liquid chromatography

Poster (1997)