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Polymeric alkenoxy amino acid surfactants: II. Chiral separations of β‐blockers with multiple stereogenic centers
Author(s) -
Rizvi Syed A. A.,
Akbay Cevdet,
Shamsi Shahab A.
Publication year - 2004
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200305762
Subject(s) - nadolol , labetalol , enantiomer , chemistry , stereocenter , polymer , high performance liquid chromatography , chromatography , stereochemistry , nuclear chemistry , organic chemistry , enantioselective synthesis , catalysis , propranolol , medicine , blood pressure , radiology
Abstract Two amino acid‐based (leucine and isoleucine) alkenoxy micelle polymers were employed in this study for the separation of multichiral center‐bearing β‐blockers, nadolol and labetalol. These polymers include polysodium N ‐undecenoxy carbonyl‐ L ‐leucinate (poly‐ L ‐SUCL) and polysodium N ‐undecenoxy carbonyl‐ L ‐isoleucinate (poly‐ L ‐SUCIL). Detailed synthesis and characterization were reported in our previous paper [26]. It was found that poly‐ L ‐SUCIL gives better chiral separation than poly‐ L ‐SUCL for both nadolol and labetalol isomers. The use of 50–100 m M poly‐ L ‐SUCIL as a single chiral selector provided separation of four and three isomers of labetalol and nadolol, respectively. Further optimization in separation of both enantiomeric pairs of nadolol and labetalol was achieved by evaluation of type and concentration of organic solvents, capillary temperature as well type and concentration of cyclodextrins. A synergistic approach, using a combination of poly‐ L ‐SUCIL and sulfated β‐CD (S‐β‐CD) was evaluated and it showed dramatic separation for enantiomeric pairs of nadolol. On the other hand for labetalol enantiomers, separation was slightly decreased or remain unaffected using the dual chiral selector system. Finally, simultaneous separation of both nadolol and labetalol enantiomers was achieved in a single run using 25 m M poly‐ L ‐SUCIL and 5% w/v of S‐β‐CD in less then 35 min highlighting the importance of high‐throughput chiral analysis.