A POLAROGRAPHIC METHOD FOR THE DETERMINATION OF DIGITOXIN AND GITOXIN AND ITS APPLICATION TO PHARMACOLOGICAL STUDIES

¹ Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, Virginia

A study of the polarographic characteristics of digitoxin and gitoxin has been carried out and the results showed that digitoxin gives an average half wave potential of -1.965 volts and gitoxin gives a half wave potential of -1.960 volts. Both of these drugs give height of polarographic break versus concentration curves of such a type that low concentrations of the order of 2 to 20 microgm. per cent or lower may be determined.

A method for the analysis of tincture of digitalis has been proposed which is based upon the solubility and polarographic properties of digitoxin and gitoxin. This method requires only 1 ml. of tincture for analysis and will measure as low as 10 microgm. per cent of either drug in the original solution.

A study of digitoxin in blood has been made and the results show that all of the added digitoxin is not extractable. It has also been shown that all of the extractable digitoxin is present in the plasma fraction of the blood. The disappearance rate of digitoxin from the circulating blood of dogs is very rapid and follows closely a curve of the form C = nT^a where C equals concentration in microgram per cent at time T after injection and n and a are determined constants.