Determination of GDC-0449, a small-molecule inhibitor of the Hedgehog signaling pathway, in human plasma by solid phase extraction-liquid chromatographic-tandem mass spectrometry.

To support clinical development, a solid phase extraction (SPE) liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method for the determination of GDC-0449 concentrations in human plasma has been developed and validated. Samples (200 microl) were extracted using an Oasis MCX 10 mg 96-well SPE plate and the resulting extracts were analyzed using reverse-phase chromatography coupled with a turbo-ionspray interface. The method was validated over calibration curve range 5-5000 ng/mL. Quadratic regression and 1/x(2) weighing were used. Within-run relative standard deviation (%RSD) was within 10.1% and accuracy ranged from 88.6% to 109.0% of nominal. Between-run %RSD was within 8.6% and accuracy ranged from 92.4% to 105.3% of nominal. Extraction recovery of GDC-0449 was between 88.3% and 91.2% as assessed using quality control sample concentrations. GDC-0449 was stable in plasma for 315 days when stored at -70 degrees C and stable in reconstituted sample extracts for 117 h when stored at room temperature. Quantitative matrix effect/ion suppression experiment was performed and no significant matrix ion suppression was observed. This assay allows for the determination of GDC-0449 plasma concentrations over a sufficient time period to determine pharmacokinetic parameters at relevant clinical doses.

Recent advances in chromatographic and mass spectrometric methods for determination of LSD and its metabolites in physiological specimens.

The detection of LSD use continues to be a challenge for toxicology laboratories due to the very low concentrations of LSD and its metabolites in body fluids. However, significant progress has been made in the development of more sensitive and specific analytical methods. Techniques that have proven particularly effective include: (1) immunoaffinity extraction, (2) gas chromatography coupled with chemical ionization and tandem mass spectrometric detection, and (3) liquid chromatography in combination with electrospray ionization and either single-stage or tandem mass spectrometric detection. In addition, a major metabolite of LSD, 2-oxo-3-hydroxy-LSD, has been identified and found to be present in far higher concentrations than LSD in most LSD-positive urine samples.

Quantitative determination of LSD and a major metabolite, 2-oxo-3-hydroxy-LSD, in human urine by solid-phase extraction and gas chromatography-tandem mass spectrometry.

An assay has been developed for quantitative determination of lysergic acid diethylamide (LSD) and a major metabolite of LSD in human urine at concentrations as low as 10 pg/mL. In most LSD-positive urine samples the metabolite, 2-oxo-3-hydroxy-LSD, is present at higher concentrations than LSD and can be detected for a longer time than LSD after ingestion of the drug. Urine samples are extracted using Varian Bond Elut Certify extraction cartridges. Confirmatory identification is accomplished by trimethylsilylation of LSD and 2-oxo-3-hydroxy-LSD, followed by gas chromatography-tandem mass spectrometry analysis using positive ion chemical ionization and selected reaction monitoring. Commercially available lysergic acid methylpropylamide and 2-oxo-3-hydroxy-LAMPA are used as internal standards. With selected reaction monitoring, both compounds gave linear calibration curves from 10 pg/mL to 5000 pg/mL. Forty-nine human urine samples that had previously been shown to contain LSD were reanalyzed by the new method. These samples showed an average LSD concentration of 357 pg/mL and an average 2-oxo-3-hydroxy-LSD concentration of 3470 pg/mL. Additional experiments using clinical samples in which two subjects were dosed with LSD support the conclusion that analysis for 2-oxo-3-hydroxy-LSD can permit identification of LSD users for a longer period following ingestion than analysis for the parent drug.

Benzoylecgonine (cocaine metabolite) detection in hair samples of jail detainees using radioimmunoassay (RIA) and gas chromatography/mass spectrometry (GC/MS).

Benzoylecgonine (BE) was detected in hair samples using nonproprietary extraction methodology and modifications of well-established radioimmunoassay (RIA) screening/quantitative gas chromatography/mass spectrometry (GC/MS) confirmation procedures. Samples collected anonymously from a population of 48 jail detainees weighed between 5.3 and 61.2 mg. All of the 22 hair samples which had RIA results indicating the presence of BE or immunologically similar substances above a cutoff amount of 1.25 ng/sample (50 ng/mL) were confirmed by GC/MS. Several varieties of hair color and texture were tested, although in each general category there were samples which contained BE as well as other samples which did not reveal detectable amounts of BE. The range of concentrations in 22 hair extracts that screened positive were 0.26 to 18 ng/mg hair as determined by GC/MS. In comparison with other reports of cocaine-related substances in hair, these data show consistent concentrations.