- Sequential metabolism of secondary alkyl amines to metabolic-intermediate complexes: Opposing roles for the secondary hydroxylamine and primary amine metabolites of desipramine, (S)-fluoxetine, and N-desmethyldiltiazem
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Three secondary amines desipramine (DES), (S)-fluoxetine [(S)-FLX], and N-desmethyldiltiazem (MA) undergo N-hydroxylation to the corresponding secondary hydroxylamines [N-hydroxydesipramine, (S)-N-hydroxyfluoxetine, and N-hydroxy-N-desmethyldiltiazem] by cytochromes P450 2C11, 2C19, and 3A4, respectively. The expected primary amine products, N-desmethyldesipramine, (S)-norfluoxetine, and N,N-didesmethyldiltiazem, are also observed. The formation of metabolic-intermediate (MI) complexes from these substrates and metabolites was examined. In each example, the initial rates of MI complex accumulation followed the order secondary hydroxylamine > secondary amine ? primary amine, suggesting that the primary amine metabolites do not contribute to formation of MI complexes from these secondary amines. Furthermore, the primary amine metabolites, which accumulate in incubations of the secondary amines, inhibit MI complex formation. Mass balance studies provided estimates of the product ratios of N-dealkylation to N-hydroxylation. The ratios were 2.9 (DES-CYP2C11), 3.6 [(S)-FLX-CYP2C19], and 0.8 (MA-CYP3A4), indicating that secondary hydroxylamines are significant metabolites of the P450-mediated metabolism of secondary alkyl amines. Parallel studies with N-methyl-d3-desipramine and CYP2C11 demonstrated significant isotopically sensitive switching from N-demethylation to N-hydroxylation. These findings demonstrate that the major pathway to MI complex formation from these secondary amines arises from N-hydroxylation rather than N-dealkylation and that the primary amines are significant competitive inhibitors of MI complex formation. Copyright
- Hanson, Kelsey L.,VandenBrink, Brooke M.,Babu, Kantipudi N.,Allen, Kyle E.,Nelson, Wendel L.,Kunze, Kent L.
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experimental part
p. 963 - 972
(2011/03/18)
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- Stereoselective inhibition of serotonin re-uptake and phosphodiesterase by dual inhibitors as potential agents for depression
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Multi-target compounds where more than one functional activity is incorporated into the same molecule may have advantages in treating disease states. Selective serotonin re-uptake inhibitors (SSRIs)a (i.e., (R)- and (S)-norfluoxetine) were chemically linked to a PDE4 inhibitor via a five carbon bridge. The new dual PDE4 inhibitor/SSRIs (i.e., (R)-8 and (S)-8) showed moderately potent but highly selective serotonin re-uptake inhibition (IC50 values of 173 and 42 nM, respectively) in vitro. The dual PDE4 inhibitor/SSRIs (R)-8 and (S)-8 also inhibited PDE4D2 (i.e., Ki values of 106 and 253 nM, respectively). Due to the synergistic functional activity, PDE4 inhibitor/SSRIs may be effective in treating diseases such as depression.
- Cashman, John R.,Voelker, Troy,Johnson, Robert,Janowsky, Aaron
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p. 337 - 343
(2011/03/17)
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- MODULATORS OF CENTRAL NERVOUS SYSTEM NEUROTRANSMITTERS
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Disclosed are agents having pharmacological activity against cellular receptors and intracellular singaling, particularly receptors and sigaling pathways of central nervous system (CNS) neurotransmitters. Also disclosed are related methods and compositions for the treatment or prevention of diseases or disorders using the agents.
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Page/Page column 148-149
(2010/10/20)
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- Chemoenzymatic synthesis2 of both enantiomers of fluoxetine, tomoxetine and nisoxetine: Lipase-catalyzed resolution of 3-aryl-3-hydroxypropanenitriles
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A facile preparation of (±)-3-hydroxy-3-phenylpropanenitrile has been carried out by ring-opening of styrene oxide with NaCN in aqueous ethanol. Subsequent kinetic resolution of this material via lipase-mediated transesterification gave the S-alcohol and R-acetate in excellent yields and high enantioselectivities, particularly with lipase PS-C 'Amano' II. The effect of solvents and immobilization of the lipase has also been investigated. It is interesting to note that the use of immobilized lipase for this transesterification process in hydrophobic solvents (diisopropyl ether, toluene and hexane) enhanced the reaction rate drastically and gave optimal yields with high enantioselectivity (>99%). Moreover, enantiopure 3-hydroxy-3-phenylpropanenitrile products have been converted via enantioconvergent routes into the (R)- and (S)-enantiomers of the important anti-depressants fluoxetine, tomoxetine, nisoxetine and norfluoxetine.
- Kamal, Ahmed,Khanna,Ramu
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p. 2039 - 2051
(2007/10/03)
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- Synthesis of R- and S- fluoxetine, norfluoxetine and related compounds from styrene oxide
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A facile, high yield synthesis of R-- or S--fluoxetine and norfluoxetine is described. This synthetic route utilizes readily available starting materials.
- Mitchell,Koenig
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p. 1231 - 1238
(2007/10/02)
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