Determining thermodynamic quantities of micellar solubilization of chiral pharmaceutical compounds in aqueous solutions of N-dodecoxycarbonylvaline using micellar electrokinetic chromatography

✍ Scribed by Alicia G. Peterson; Joe P. Foley

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 843 KB
• Volume: 8
• Category: Article
• ISSN: 1040-7685
• DOI: 10.1002/(sici)1520-667x(1996)8:6<427::aid-mcs8>3.0.co;2-3

✦ Synopsis

Using the van't Hoff relationship, the enthalpy and entropy of transfer from the aqueous to a chiral micellar phase was measured for 12 pairs of enantiomeric pharmaceutical compounds, including p-agonists, p-blockers, and other p-amino alcohols. Selectivities, distribution coefficients, and Gibbs free energies were also determined. Whereas the transfer of solute from aqueous phase to the chiral micellar phase was always favorable from an enthalpic viewpoint ( -19 < AH" < -4 kJ/mol), it was not always so from an entropic perspective (-12.1 < AS" < 56.9 J mol-' K-'). Dramatic differences in AH" and AS" were often observed between enantiomers. The enthalpy and entropy changes for the solutes follow a linear free-energy relationship, indicating a similar enantiomeric mechanism of separation. Relationships between analyte structure and thermodynamic parameters were investigated to better understand the interactions of enantiomers with N-dodecoxycarbonylvaline micelles.