STABILIZATION OF DIGITALIS GLYCOSIDES THROUGH 2-HYDROXYPROPYL-BETA-CYCLODEXTRIN COMPLEXATION IN AQUEOUS-SOLUTION AT PH 7.3

The effect of 2-hydroxypropyl-beta-cyclodextrin (2 HP-beta-CyD) on the stability of digitoxin and digoxin in aqueous solutions at pH 7.3 was investigated. At higher temperatures no difference in degradation was observed in solutions with or without 2 HP-beta-CyD. This indicate a low stability of the glycoside-2 HP-beta-CyD complex at higher temperatures, yielding more free glycoside, not protected against degradation. At lower temperatures, however, (20-degrees-C, 30-degrees-C and 40-degrees-C) 2HP-beta-CyD showed a stabilizing effect on the glycosides. This appeared already at a molecular ratio of 1:5 but did not increase with increasing cyclodextrin (CyD) concentrations. During steam sterilization (121-degrees-C, 20 min) digitoxin and digoxin were protected against degradation by 2HP-beta-CyD complexation.