Evaluation of a new kind of cation exchange restricted access sorbent for on-line solid phase extraction of basic drugs from plasma prior to their determination by liquid chromatography

Poster (2002)

Statistical analysis of the validation results: diagnostic or decision tools

Conference (2002)

Objectifs des méthodes analytiques et objectifs de la validation. Comment les réconcilier pour garantir la qualité des résultats ?

Conference (2002)

Separation and simultaneous determination of S-timolol maleate, its optical antipode and related substances by liquid chromatography using a cellulose based chiral stationary phase

Conference (2001, May 25)

Development and Validation of an Automated Method for the Liquid Chromatographic Determination of Sotalol in Plasma Using Dialysis and Trace Enrichment on a Cation-Exchange Pre-Column as on-Line Sample Preparation

in Journal of Pharmaceutical & Biomedical Analysis (2001), 24(5-6), 801-14

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

A fully automated method for the determination of sotalol in human plasma was developed, involving dialysis through a cellulose acetate membrane, clean-up and enrichment of the dialysate on a strong cation-exchange pre-column and subsequent liquid chromatographic (LC) analysis with UV detection. All sample handling operations were carried out by means of an ASTED system. Before starting dialysis, the trace enrichment column (TEC) was conditioned. The plasma sample, to which the internal standard (atenolol) was automatically added, was then loaded in the donor channel and was kept static while the dialysis liquid, consisting of 0.017 M acetic acid, was passed through the acceptor channel in successive pulses. After each pulse, the dialysate was dispensed onto the TEC. When dialysis was discontinued, the analytes were eluted from the TEC by the LC mobile phase by rotation of a switching valve and transferred to the analytical column packed with octyl silica. The LC mobile phase was a mixture of methanol and pH 7.0 phosphate buffer containing 1-octanesulfonate at a concentration of 7.5 x 10(-4) M (19:81; v/v). The UV detection was performed at 230 nm. The influence of several parameters of the dialysis and trace enrichment processes on analyte recovery and method selectivity was investigated. The method was then validated. The mean absolute recovery for sotalol was about 60%. The limit of quantitation was 25 ng/ml and R.S.D. for repeatability and intermediate precision obtained at a concentration level of 50 ng/ml were 4.3 and 5.8%, respectively. [less ▲]

Développements récents dans le domaine de la validation de méthodes en analyse pharmaceutique et biomédicale

Conference (2001)

Objectives of validation : the statistical rationale of the SFSTP

Conference (2001)

Liquid chromatographic analysis of local anesthetics in human plasma after sample preparation by on-line dialysis. Optimization by use of experimental design

in Chromatographia (2001), 53(11-12), 678-686

A fully automated method involving dialysis, clean-up and enrichment of the dialysate on a pre-column packed with a strong cation-exchange phase, and subsequent liquid chromatographic (LC) analysis with ... [more ▼]

A fully automated method involving dialysis, clean-up and enrichment of the dialysate on a pre-column packed with a strong cation-exchange phase, and subsequent liquid chromatographic (LC) analysis with UV detection at 220 nm has been developed for the determination of local anesthetics (prilocaine, mepivacaine, and bupivacaine) in human plasma. All sample-handling operations were executed automatically by means of an Asted XI system. To identify the most important conditions affecting analyte recovery from the dialysis and trace-enrichment processes, a seven-factor D-optimal design with 16 experimental points was elaborated as a screening test A four-factor D-optimal design with 24 experimental points was then used to predict and optimize analyte recovery. Derringer's desirability function was also used to deduce optimum conditions for analyte recovery and dialysis time within the experimental domain. Finally, the method developed was validated. Mean recoveries were approximately 72% for bupivacaine and approximately 67% for mepivacaine and prilocaine. The limits of quantification were 28 ng mL(-1) for bupivacaine and 25 ng mL(-1) for mepivacaine and prilocaine. [less ▲]

Determination of Albendazole and Its Main Metabolites in Ovine Plasma by Liquid Chromatography with Dialysis as an Integrated Sample Preparation Technique

in Journal of Chromatography. A (2000), 870(1-2), 121-34

Albendazole is a benzimidazole derivative with a broad-spectrum activity against human and animal helminth parasites. In order to determine the main pharmacokinetic parameters in sheep after oral and ... [more ▼]

Albendazole is a benzimidazole derivative with a broad-spectrum activity against human and animal helminth parasites. In order to determine the main pharmacokinetic parameters in sheep after oral and intravenous administration of a new formulation of albendazole (an aqueous solution), a fully automated method was developed for the determination of this drug and its main metabolites, albendazole sulfoxide (active metabolite) and sulfone in ovine plasma. This method involves dialysis as purification step, followed by enrichment of the dialysate on a precolumn and liquid chromatography (LC). All sample handling operations were executed automatically by means of an ASTED XL system. After conditioning of the trace enrichment column (TEC) packed with octadecyl silica with pH 6.0 phosphate buffer containing sodium azide, the plasma sample, in which a protein releasing reagent (1 M HCl) containing Triton X-100 was automatically added, was loaded in the donor channel and dialysed on a cellulose acetate membrane in the static-pulsed mode. The dialysis liquid consisted of pH 2.5 phosphate buffer. By rotation of a switching valve, the analytes were eluted from the TEC in the back-flush mode by the LC mobile phase and transferred to the analytical column, packed with octyl silica. The chromatographic separation was performed at 35 degrees C and the analytes were monitored photometrically at 295 nm. Due to the differences in hydrophobic character between albendazole and its metabolites, a gradient elution was applied. The mobile phase consisted of a mixture of acetonitrile and pH 6.0 phosphate buffer. The proportion of organic modifier was increased from 10.0 to 50.1% in 12.30 min, then from 50.1 to 66.9% in 1.70 min. First, the gradient conditions and the temperature were optimised for the LC separation using the DryLab software. Then, the influence of some parameters of the dialysis process on analyte recovery was investigated. Finally, the method developed was validated. The mean recoveries for albendazole and its metabolites were about 70 and 65%, respectively. The limits of quantification for albendazole and its metabolites were 10 and 7.5 ng/ml, respectively. [less ▲]

Techniques de préparation basées sur l'utilisation de membranes pour le traitement des échantillons biologiques préalable à leur analyse chromatographique

in STP Pharma Pratiques (2000), 10(6), 361-374