HPLC for Pharmaceutical Scientists (Kazakevich/HPLC for Pharmaceutical Scientists) || Chiral Separations

✍ Scribed by Kazakevich, Yuri; LoBrutto, Rosario

• Publisher: John Wiley & Sons, Inc.
• Year: 2006
• Tongue: English
• Weight: 997 KB
• Edition: 1
• Category: Article
• ISBN: 0471681628
• DOI: 10.1002/9780470087954.ch22

✦ Synopsis

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