Comparison of electrophoretic methods for dextromethorphan metabolites separation prepared by in vitro incubations
Authors | |
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Year of publication | 2008 |
Type | Article in Proceedings |
Conference | Book of Abstracts CECE 2008 |
MU Faculty or unit | |
Citation | |
Field | Biochemistry |
Keywords | phase I metabolites; microsomes; drug metabolism; CE methods |
Description | Characterization of phase I metabolites is an inevitable part of research and development of new drug entities. In vitro studies accomplished under the action of microsomes represent the appropriate tool for drug metabolism examination. Human liver microsomes credibly mimic natural enzymatic system involved in metabolism of different endogenous and exogenous compounds. Microsomes are the source of cytochromes P450, enzymes of phase I biotransformation. Dextromethorphan (DEX) was chosen as a probe substrate of cytochrome P450 (CYP) isoform 2D6. However, CYP isoform 3A4 also contributes to its metabolism three metabolites are expected; namely 3-methoxymorphinan, 3-hydroxymorphinan a dextrorphan. To study DEX transformation, off-line and on-line modes of incubation were tested. Methods of capillary electrophoresis have been applied to different pharmaceutical and clinical problems, e.g. determination of drugs, metabolites and biomarkers [1-3]. The capillary is an implement of separation; on the other hand it can serve as a micro vessel as well. The aim of this work is the comparison of methods applied on DEX metabolite separation. The metabolites prepared by off-line incubation were successfully separated in tetraborate buffer (80 mM; pH 9.85) at temperature 25C. As for on-line mode both, incubation and separation conditions have to be compatible, the partial filling method [4] and re-optimization of background electrolyte were necessary. The favorable metabolite separation was obtained with electrolyte containing linear polyacrylamide (10%, v/v) and 2-propanol (10%, v/v) at 37C. The particular parts of methods, namely injection procedure, separation parameters and conditioning are discussed. |
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