In vitro stability of proscillaridin A.

In an in vitro study, proscillardin A was found to be rapidly inactivated at low pH. More than 50 per cent of its activity, measured by 86Rb assay, was lost after incubation for 15 minutes at pH 1 and 37 degrees C. Compared with proscillaridin, the rate of inactivation of digoxin was lower in these experiments. The rapid inactivation of proscillaridin might be of clinical importance when treating patients with this glycoside.