title: Tracking of enantioselective solubility of rac-norgestrel in the presence of cyclodextrin by a CD spectroscopic method.
abstract: Dissolution of hydrophobic rac-norgestrel in aqueous gamma-cyclodextrin (gamma-CyD) and hydroxypropyl-gamma-cyclodextrin (HP-gamma-CyD) solutions was investigated, and enantioselective dissolution was observed. (-)-Norgestrel, the eutomer molecule, was dissolved to a greater extent using each of the CyDs, although the effect was more significant in the case of HP-gamma-CyD. A circular dichroism (CD) spectroscopic method based on measurement of the anisotropy factor was applied for the determination of the enantiomer ratio. The concentration and the enantiomer ratio of norgestrel were determined indirectly in octanol after extraction. Optical rotation dispersion (ORD) measurements could confirm that neither the free CyDs nor their inclusion complexes could get into the organic phase during transport to octanol. Only the norgestrel molecules were able to get into the organic phase, although the enantiomer ratio remained the same as was obtained in the aqueous CyD solution.
authors.affiliation: Department of Pharmaceutical Chemistry, Semmelweis University, Högyes E. Street 9, H-1092 Budapest, Hungary.
authors.forename: Dávid
authors.initials: D
authors.lastname: Szegvári
authors.forename: Romána
authors.initials: R
authors.lastname: Zelkó
authors.forename: Péter
authors.initials: P
authors.lastname: Horváth
authors.forename: András
authors.initials: A
authors.lastname: Gergely
mesh_terms: D002942:Circular Dichroism / Q000379:methods*; D003505:Cyclodextrins / Q000032:analysis / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D008956:Models, Chemical; D008958:Models, Molecular; D009644:Norgestrel / Q000032:analysis / Q000737:chemistry*; D000442:Octanols / Q000737:chemistry; D012995:Solubility; D013237:Stereoisomerism; D013997:Time Factors; D047408:gamma-Cyclodextrins / Q000737:chemistry
chemical_list: D003505:Cyclodextrins; D000442:Octanols; D047408:gamma-Cyclodextrins; D009644:Norgestrel