Simultaneous determination of metabolic stability and identification of buspirone metabolites using multiple column fast liquid chromatography time-of-flight mass spectrometry.

A recent trend in the drug discovery and development process is to shift the starting point of drug metabolism and pharmacokinetic (DMPK) studies to a time as early as possible in the development chain to address potential issues in parallel with the optimization of the drug's lead structure. Therefore, it is necessary to develop assay methods to determine early adsorption, distribution, metabolism and excretion (ADME) parameters like metabolic stability and metabolite identification. For metabolite identification it is of crucial importance to work with fast liquid chromatography/mass spectrometry (LC/MS) systems, which provide the necessary high throughput functionalities to handle a large number of samples in combination with high speed and high resolution chromatography as well as mass accuracy.

Automated software-guided identification of new buspirone metabolites using capillary LC coupled to ion trap and TOF mass spectrometry.

The identification and structure elucidation of drug metabolites is one of the main objectives in in vitro ADME studies. Typical modern methodologies involve incubation of the drug with subcellular fractions to simulate metabolism followed by LC-MS/MS or LC-MS(n) analysis and chemometric approaches for the extraction of the metabolites. The objective of this work was the software-guided identification and structure elucidation of major and minor buspirone metabolites using capillary LC as a separation technique and ion trap MS(n) as well as electrospray ionization orthogonal acceleration time-of-flight (ESI oaTOF) mass spectrometry as detection techniques.

LC-nanospray-MS/MS analysis of hydrophobic proteins from membrane protein complexes isolated by blue-native electrophoresis.

The application of two-dimensional electrophoresis for the identification of hydrophobic membrane proteins is principally hampered by precipitation of many of these proteins during first-dimension, isoelectric focusing. Therefore new strategies towards the identification and characterization of membrane proteins are being developed. In this work we present a direct and rapid approach from blue-native gels to mass spectrometry, which allows the analyses of complete complexes and prevents protein aggregation of hydrophobic regions during electrophoresis.

Artifact production in the assay of anhydroecgonine methyl ester in serum using gas chromatography-mass spectrometry.

The detection of the pyrolysis product anhydroecgonine methyl ester (AEME, methylecgonidine) after cocaine smoking using gas chromatography-mass spectrometry is hampered by the artifactual production of AEME. The amount of AEME increases with the amount of cocaine used producing false positive values in authentic samples. A method for the correction of quantitative values was established using calibration of pyrolysis and estimation of the artifactual AEME.

Studies on in vitro degradation of anhydroecgonine methyl ester (methylecgonidine) in human plasma.

The presence of the cocaine pyrolysis product anhydroecgonine methyl ester (AEME, methylecgonidine) in plasma indicates the smoking of cocaine. The stability of this analyte in human plasma has not been studied. In the present investigation AEME and its hydrolysis product anhydroecgonine (AE, ecgonidine) were assayed in plasma and buffers using gas chromatography-mass spectrometry.

Studies on hydrolytic and oxidative metabolic pathways of anhydroecgonine methyl ester (methylecgonidine) using microsomal preparations from rat organs.

During smoking of cocaine-base (crack), anhydroecgonine methyl ester (AEME, methylecgonidine) is formed in large amounts as a pyrolysis product of cocaine and is absorbed in the lungs. The metabolism of AEME was studied in the present investigation using microsome preparations from rat liver, lung, kidney, and brain. Potential metabolites of AEME were synthesized and used as substrate to complement the experiments.

Identification of anhydroecgonine methyl ester N-oxide, a new metabolite of anhydroecgonine methyl ester, using electrospray mass spectrometry.

Cocaine is transformed into hepatotoxic metabolites through oxidative pathways. For anhydroecgonine methyl ester (AEME), the main constituent in crack smoke, the oxidative metabolism has not been studied. Therefore, incubation of AEME with rat liver microsomes was performed and a metabolite of AEME, anhydroecgonine methyl ester N-oxide (AEMENO), was identified.

A fatal human intoxication with the herbicide allyl alcohol (2-propen-1-ol).

Oral ingestion of allyl alcohol by a 55-year-old man resulted in death within 100 min. At autopsy, bloody, reddish fluid was found in mouth, larynx, esophagus, and trachea. The mucous membranes of the trachea, stomach, and duodenum were congested and inflamed.