| Title: | Liquid chromatography/tandem mass spectrometric bioanalysis using normal-phase columns with aqueous/organic mobile phases - a novel approach of eliminating evaporation and reconstitution steps in 96-well SPE |
| Author(s): | Naidong W; Shou WZ; Addison T; Maleki S; Jiang X; |
| Address: | "Bioanalytical Chemistry Department, Covance Laboratories, Inc., 3301 Kinsman Boulevard, Madison, WI 53704, USA. naidong.weng@covance.com" |
| Journal Title: | Rapid Commun Mass Spectrom |
| ISSN/ISBN: | 0951-4198 (Print) 0951-4198 (Linking) |
| Abstract: | "Bioanalytical methods using automated 96-well solid-phase extraction (SPE) and liquid chromatography with electrospray tandem mass spectrometry (LC/MS/MS) are widely used in the pharmaceutical industry. SPE methods typically require manual steps of drying of the eluates and reconstituting of the analytes with a suitable injection solvent possessing elution strength weaker than the mobile phase. In this study, we demonstrated a novel approach of eliminating these two steps in 96-well SPE by using normal-phase LC/MS/MS methods with low aqueous/high organic mobile phases, which consisted of 70-95% organic solvent, 5-30% water, and small amount of volatile acid or buffer. While the commonly used SPE elution solvents (i.e. acetonitrile and methanol) have stronger elution strength than a mobile phase on reversed-phase chromatography, they are weaker elution solvents than a mobile phase for normal-phase LC/MS/MS and therefore can be injected directly. Analytical methods for a range of polar pharmaceutical compounds, namely, omeprazole, metoprolol, fexofenadine, pseudoephedrine as well as rifampin and its metabolite 25-desacetyl-rifampin, in biological fluids, were developed and optimized based on the foregoing principles. As a result of the time saving, a batch of 96 samples could be processed in one hour. These bioanalytical LC/MS/MS methods were validated according to 'Guidance for Industry - Bioanalytical Method Validation' recommended by the Food and Drug Administration (FDA) of the United States" |
| Keywords: | "Adrenergic beta-Antagonists/analysis/blood Bronchodilator Agents/analysis/blood Chromatography, Liquid Ephedrine/analysis/blood Histamine H1 Antagonists/analysis/blood Humans Leprostatic Agents/analysis/blood Metoprolol/analysis/blood Pharmaceutical Prepa;" |
| Notes: | "MedlineNaidong, Weng Shou, Wilson Z Addison, Thomas Maleki, Saber Jiang, Xiangyu eng England 2002/10/04 Rapid Commun Mass Spectrom. 2002; 16(20):1965-75. doi: 10.1002/rcm.817" |
