Retention behavior of cardiac steroids using cyclodextrin in the mobile phase in high-performance liquid chromatography.
The retention behaviour of twenty cardiac steroids and four fluorescent derivatives was examined by the addition of cyclodextrin to the mobile phase in reversed-phase high-performance liquid chromatography. The addition of a suitable cyclodextrin improved the separation of isomeric cardiac steroids. The steroid A/B ring junction is the most important factor in the choice of the optimum cyclodextrin to be added; the C/D ring junction is less important. The hydroxyl group at the 3- or 12-position of the steroid enhanced the changes in retention times of these compounds. The effect of an unsaturated lactone ring at the 17 beta-position on the retention in the presence of cyclodextrin was also determined with cardenolide (five-membered ring) and bufadienolide (six-membered ring) but little difference was observed. Isomeric cardiac steroids, whose separation has not been done by the conventional method, were clearly separated by this method. The fluorescence intensity of 3-(1-anthroyl)-cardiac steroid was enhanced by the addition of cyclodextrin to the mobile phase.
Shimada
K
K
Faculty of Pharmaceutical Sciences, Kanazawa University, Japan.
Oe
T
T
Hirose
Y
Y
Komine
Y
Y
D000818:Animals; D002298:Cardenolides / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003505:Cyclodextrins; D003912:Dextrins; D004073:Digitoxigenin / Q000032:analysis*; D005453:Fluorescence; D006321:Heart / Q000502:physiology; D006801:Humans; D013213:Starch; D013256:Steroids / Q000032:analysis / Q000502:physiology*
D002298:Cardenolides; D003505:Cyclodextrins; D003912:Dextrins; D013256:Steroids; D004073:Digitoxigenin; D013213:Starch