References of "Chiap, Patrice"
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See detailValidation of bioanalytical methods
Hubert, Philippe ULg; Chiap, Patrice ULg; Ceccato, Attilio ULg et al

in Journal de Pharmacie de Belgique (1995), 50

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See detailAutomated determination of camazepam in human plasma by solid phase extraction coupled to HPLC
Hubert, Philippe ULg; Chiap, Patrice ULg; Ceccato, Attilio ULg et al

in Journal de Pharmacie de Belgique (1995), 50

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See detailOn-line combination of dialysis and liquid chromatography for the automated determination of oxprenolol in human plasma
Toussaint, B.; Ceccato, Attilio ULg; Chiap, Patrice ULg et al

in Journal de Pharmacie de Belgique (1995), 50

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See detailKnowledge-Based System for the Automated Solid-Phase Extraction of Basic Drugs from Plasma Coupled with Their Liquid Chromatographic Determination. Application to the Biodetermination of Beta-Receptor Blocking Agents
Hubert, Philippe ULg; Chiap, Patrice ULg; Moors, M. et al

in Journal of Chromatography. A (1994), 665(1), 87-99

Techniques for the preparation of biological samples are often based nowadays on solid-phase extraction (SPE). The different SPE steps can be performed automatically on disposable extraction cartridges ... [more ▼]

Techniques for the preparation of biological samples are often based nowadays on solid-phase extraction (SPE). The different SPE steps can be performed automatically on disposable extraction cartridges (DECs) by means of a sample processor. A knowledge-based system was developed to facilitate the development of fully automated methods for the solid-phase extraction of relatively hydrophobic basic drugs from plasma, coupled with their determination by high-performance liquid chromatography (HPLC). The DEC filled with 50 mg of cyanopropyl-bonded silica phase is first conditioned with methanol and buffer solution (pH 7.4). After sample application, the DEC sorbent is washed with the same buffer. The analytes are then desorbed with an appropriate eluent and the eluate is finally diluted with the same buffer as used in the HPLC mobile phase before injection. Under these conditions, only three variables are still to be optimized: the composition and volume of the elution solvent and the volume of buffer to be added to the eluate. On the basis of this general strategy, a decision tree providing information about suggested starting conditions and guidelines for the optimization of the three variables was developed and implemented by use of a hypermedia software. This didactic expert system was evaluated using several beta-receptor blocking agents as model compounds and the operating conditions obtained for the automated SPE of these compounds are presented. A method for the determination of propranolol in plasma using the SPE conditions deduced from the knowledge-based system was validated. The absolute recovery of propranolol is ca. 93% and the limit of detection is 1.3 ng ml-1. The mean within-day and between-day reproducibilities are 2.3 and 3.6%, respectively. [less ▲]

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See detailA knowledge-based system for developping solid-phase extraction methods with the ASPEC system, chapitre #D-3
Moors, M.; Bourguignon, B.; Massart, D. L. et al

in Reid, E.; Hill, H. M.; Wilson, I. D. (Eds.) Biofluid and tissue analysis for drugs, including hypolipidaemics (1994)

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See detailFully Automated Determination of Sulfamethazine in Ovine Plasma Using Solid-Phase Extraction on Disposable Cartridges and Liquid Chromatography
Hubert, Philippe ULg; Chiap, Patrice ULg; Evrard, Brigitte ULg et al

in Journal of Chromatography. A (1993), 622(1), 53-60

An automatic sample preparation procedure followed by on-line injection of the sample extract into a HPLC system has been developed for the quantitative analysis of sulfamethazine and its N4-acetyl ... [more ▼]

An automatic sample preparation procedure followed by on-line injection of the sample extract into a HPLC system has been developed for the quantitative analysis of sulfamethazine and its N4-acetyl metabolite in ovine plasma. The sample clean-up was performed by solid-phase extraction (SPE) on C18 disposable extraction cartridges (DECs). All the sample handling operations were effected by a robotic auto-sampler. The DEC was first conditioned with methanol and phosphate buffer pH 7.4. After loading 1.0 ml of plasma sample onto the DEC, the latter was washed with the same buffer. The elution step was performed with methanol (0.25 ml) and the eluate was then diluted by adding 0.75 ml volume of phosphate buffer pH 6.4. A 20-microliters volume of the resultant solution was injected onto an octadecyl silica column preceded by a short guard column. The HPLC mobile phase was methanol-phosphate buffer pH 6.4 (25:75, v/v). Sulfamethazine and N4-acetylsulfamethazine were determined photometrically at 262 nm. Under these conditions, linear calibration curves ranging from 2 to 250 micrograms ml-1 have been obtained for both compounds. Drug recoveries were higher than 90% and typical relative standard deviation values were 0.7% (within-day) and 2.0% (between-day) at a plasma concentration of 50 micrograms ml-1. [less ▲]

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