TAILIEUCHUNG - HPLC for Pharmaceutical Scientists 2007 (Part 22)

Chirality plays a major role in biological processes, and the enantiomers of a bioactive molecule often possess different biological effects. For example, all pharmacological activity may reside in one enantiomer of a molecule, or enantiomers may have identical qualitative and quantitative pharmacological activity. In some cases, enantiomers may have qualitatively similar pharmacological activity, but different quantitative potencies. Since drugs that are produced by chemical synthesis are usually a mixture of enantiomers, there is a need to quantify the level of the isomeric impurity in the active pharmaceutical ingredient. . | 22 CHIRAL SEPARATION Nelu Grinberg Thomas Burakowski and Apryll M. Stalcup INTRODUCTION Chirality plays a major role in biological processes and the enantiomers of a bioactive molecule often possess different biological effects. For example all pharmacological activity may reside in one enantiomer of a molecule or enantiomers may have identical qualitative and quantitative pharmacological activity. In some cases enantiomers may have qualitatively similar pharmacological activity but different quantitative potencies. Since drugs that are produced by chemical synthesis are usually a mixture of enantiomers there is a need to quantify the level of the isomeric impurity in the active pharmaceutical ingredient. Accurate assessment of the enantiomeric purity of substances is critical because isomeric impurities may have unwanted toxicological pharmacological or other effects. Such impurities may be carried through a synthesis and preferentially react at one or more steps and yield an undesirable level of another impurity. The determination of a trace enantiomeric impurity in a sample of a single enantiomer drug substance in the presence of a range of other structurally related impurities and a large excess of the major enantiomer remains challenging. The history of enantiomeric separation starts with the work of Pasteur. In 1848 he discovered that the spontaneous resolution of racemic ammonium sodium tartrate yielded two enantiomorphic crystals. Individual solutions of these enantiomorphic crystals led to a levo and dextro rotation of the polarized light. Because the difference of the optical rotation was observed in solution Pasteur suggested that like the two sets of crystals the molecules are HPLC for Pharmaceutical Scientists Edited by Yuri Kazakevich and Rosario LoBrutto Copyright 2007 by John Wiley Sons Inc. 987 988 CHIRAL SEPARATION mirror images of each other and the phenomenon is due to the molecular asymmetry 1 . While Pasteur made the historical discovery

• Y học thường thức
• chiral separation
• HPLC
• Pharmaceutical Scientists 2007
• HPLC Theory
• tài liệu chuyên ngành dược
• sách học dược sĩ
• Chiral separation techniques
• Membranes in chiral
• Separations
• Enantiomer separations
• Designed imprinted chiral phases
• Preparative chiral separations
• Method development
• Glycopeptide chiral stationary phases
• Enantiomeric separations
• Chromatography A
• Cyclodextrin electrokinetic chromatography
• Dual systems
• Dubsky’s model
• Electrokinetic chromatography
• Computer simulation
• Norpseudoephedrine stereoisomers
• Cyclodextrin chiral ionic liquids dual systems
• Enantiomeric separation
• Capillary electrokinetic chromatography
• Gas chromatography
• Cinchona alkaloid based chiral stationary phases
• Fluorinated ß phenylalanine derivatives
• Liquid chromatography
• Thermodynamic characterization
• Enantiomer elution order
• Polar organic mode
• Neat methanol
• Capillary electrophoresis
• Enantiomer migration order
• Supramolecular interactions
• Entropy change
• Enthalpy change
• Adsorption sites
• Chiral separation mechanism
• Tetrahydro ß carboline analogs
• Ion exchanger chiral stationary phases
• Enantioselective separation
• Numerous alkaloids
• Deep eutectic solvents
• Ionic liquids
• Nonstandard solvents
• Reversed phase
• Anticancer drugs
• Spirodela polyrhiza
• Non target aquatic organisms
• Bee pollen
• Stationary phases
• Supercritical fluid chromatography
• Algebraic equations
• Isopulegol analogs
• Prodrug mechanism
• Novel antidiabetic drug
• Chiral chromatography
• Direct inlet tandem mass spectrometry
• Sample recycling