Fully automated systems for the liquid chromatographic determination of drug enantiomers in biological fluids

Conference (1997)

LC determination of mephobarbital enantiomers and phenobarbital in plasma using a precolumn with restricted access sorbent for sample clean-up

Poster (1997)

Automated determination of tramadol enantiomers in plasma using solid-phase extraction and chiral liquid chromatography

Poster (1997)

Automated determination of tramadol enantiomers in plasma using solid-phase extraction and chiral liquid chromatography

Poster (1997)

Automated Determination of Verapamil and Norverapamil in Human Plasma with on-Line Coupling of Dialysis to High-Performance Liquid Chromatography and Fluorometric Detection

in Journal of Chromatography. A (1996), 750(1-2), 351-60

A fully automated method for the simultaneous determination of verapamil and its main metabolite norverapamil in human plasma is described. This method is based on on-line sample preparation using ... [more ▼]

A fully automated method for the simultaneous determination of verapamil and its main metabolite norverapamil in human plasma is described. This method is based on on-line sample preparation using dialysis followed by clean-up and enrichment of the dialysate on a precolumn and subsequent HPLC analysis with fluorometric detection. All sample handling operations were performed automatically by a sample processor equipped with a robotic arm (ASTED system). The plasma samples were dialysed on a cellulose acetate membrane (cut-off: 15 kD) and the dialysate was purified and enriched on a short pre-column filled with cyanopropyl silica. Before starting dialysis, this trace enrichment column (TEC) was first conditioned with the HPLC mobile phase and then with pH 3.0 acetate buffer. 370 microliters of plasma sample spiked with the internal standard (gallopamil) were dialysed in the static-pulsed mode. The solution at the donor side was pH 3.0 acetate buffer containing Triton X-100 while the acceptor solution was made of the same acetate buffer. When dialysis was discontinued, the analytes were desorbed from the TEC by the HPLC mobile phase and transferred to the C18 analytical column by means of a switching valve. This mobile phase consisted of a mixture of acetonitrile, pH 3.0 acetate buffer and 2-aminoheptane. The influence of different parameters of the dialysis process on the recovery of verapamil and norverapamil has been studied. The effect of the volume, the aspirating and dispensing flow-rates of the dialysis solution has been investigated. The recoveries of verapamil and norverapamil in plasma were close to 75% and the limits of quantification were 5 ng/ml for both analytes. The method was found to be linear in the concentration range from 5 to 500 ng/ml (r2: 0.9996 for both analytes). The intra-day and inter-day reproducibilities at a concentration of 100 ng/ml were 2.3% and 5.6% for verapamil and 1.7% and 5.1% for norverapamil, respectively. [less ▲]

Analytical technologies and tolls for drug purity testing

Conference (1996)

On-line dialysis coupled to liquid chromatography for the automated determination of verapamil and its demethylated metabolite in plasma, chapitre "biomedical analysis with hyphenated chromatography"

in Hyphenated techniques in chromatography and hyphenated chromatographic analysers (1996)

Stability of ondansetron hydrochloride and dexamethazone sodium phosphate admixtures in injectable solutions

Conference (1996)

Injection-generated solvent and pH gradients for sample enrichment on injection of large volumes in microcolumn liquid chromatography

Poster (1995)

Validation of bioanalytical methods

in Journal de Pharmacie de Belgique (1995), 50