A 96-well screen filter plate for high-throughput biological sample preparation and LC-MS/MS analysis.

A novel 96-well screen filter plate (patent pending) has been invented to eliminate a time-consuming and labor-intensive step in preparation of in vivo study samples--to remove blood or plasma clots. These clots plug the pipet tips during a manual or automated sample-transfer step causing inaccurate pipetting or total pipetting failure. Traditionally, these blood and plasma clots are removed by picking them out manually one by one from each sample tube before any sample transfer can be made.

Optimizing Caco-2 cell monolayers to increase throughput in drug intestinal absorption analysis.

Introduction: The aim of this investigation was to evaluate methods for increasing Caco-2 cell throughput for assessing drug intestinal absorption. The use of 6-, 12-, and 24-well membranes and the effect of membrane size on permeability and the integrity of the Caco-2 cell monolayer were assessed. In an effort to optimize the assessment of drug permeability, increased throughput was investigated by testing compounds singly or as mixtures of analytes.

The use of on-line and off-line chromatographic extraction techniques coupled with mass spectrometry for support of in vivo and in vitro assays in drug discovery.

We have investigated various sample chromatographic extraction and sample preparation methods for liquid chromatography mass spectrometry analysis in order to increase the throughput of various in vivo and in vitro assays in support of drug discovery. The results indicated that direct plasma injection, although certainly faster than conventional protein precipitation for sample preparation, had problems associated with column longevity and overall robustness. Frequently a single study could not be completed without column replacement.

The determination of RWJ-38705 (tramadol N-oxide) and its metabolites in preclinical pharmacokinetic studies using LC-MS/MS.

A rapid and reliable analytical method is described for the simultaneous determination of RWJ-38705 (tramadol N-oxide) and several of its major metabolites in the plasma of Sprague-Dawley rats and Beagle dogs. Sample preparation using solid phase extraction was followed by reversed phase liquid chromatography (LC) coupled with tandem mass spectrometric (MS/MS) detection in the positive ionization mode. The assay was linear for all analytes over concentrations ranging from approximately 6 to 2000 ng/ml.

Determination of norgestimate and its metabolites in human serum using high-performance liquid chromatography with tandem mass spectrometric detection.

A rapid and reliable analytical method is described for the simultaneous determination of a synthetic progestin norgestimate (NGM), and its metabolites, 17-deacetylnorgestimate (17-DA-NGM), 3-ketonorgestimate (3-keto-NGM) and norgestrel (NGL) in human serum using reversed phase high-performance liquid chromatography (HPLC) with tandem mass spectrometric (MS-MS) detection. The assay was linear over the concentration ranges of 0.1-5.