Metabolic stability screen for drug discovery using cassette analysis and column switching.
In vitro metabolic stability assays are used to screen compounds for stability in the presence of various drug metabolizing enzymes, usually cytochrome P450 in liver preparations (e.g., liver microsomes). High-throughput metabolic stability assays using pooling methods have been developed to keep pace with screening requirements at the lead ADME optimization stage. In our laboratory, we have improved the metabolic stability assay using the cassette analysis method, column switching, and incorporated time saving techniques in method development to yield a robust method which reduces data turnaround time, increases compound throughput, and maximizes mass spectrometer usage. This method can determine metabolic stability using microsomes or hepatocytes from any species. We describe our findings following incubation of 40 different compounds with human liver microsomes and analysis by the cassette and discrete analysis methods. Similar metabolic stability results were obtained using the cassette analysis and discrete analysis method. An overall 70% time savings was achieved by pooling four new compounds into one sample for method development/MS optimization, cassetting four samples into one sample to minimize the number of injections on LC/MS/MS analysis, and using a column switching system to analyze the samples, which results in a two-fold decrease in the LC/MS/MS analysis time.
Halladay
Jason S
JS
Department of Drug Metabolism and Pharmacokinetics (MS 70), Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, USA. halladay@gene.com
Wong
Susan
S
Jaffer
Sharmin M
SM
Sinhababu
Achintya K
AK
Khojasteh-Bakht
S Cyrus
SC
D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D055808:Drug Discovery / Q000379:methods; D022781:Hepatocytes / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors
D004364:Pharmaceutical Preparations; D003577:Cytochrome P-450 Enzyme System