The manufacturers of Digalen support the claim of the identity of their product with digitoxin by stating that “Digalen is a solution of the most active glucoside of digitalis.”[31] Of course, it is very generally admitted that digitoxin is the most active principle of digitalis, though there is some question concerning its glucosidal nature.
Digalen is in fact far less active than digitoxin, as has been shown by a number of independent observers[M] (Worth Hale, 1910; Hatcher and Brody, 1910; Neave, 1907; Miller, 1908; the referee; Weis, 1912).
The essential fact which appears from the investigation of Weis is that Digalen did not behave like digitoxin in any case.
Hale also found that Digalen gave atypical actions in which the effects on the central nervous system became prominent. The referee can corroborate these observations of Hale’s on frogs, but the convulsive symptoms were prominent with some specimens of Digalen on mammals, though not with others, the more recent specimens of the preparation showing the action prominently.
The results of all these biologic tests, as well as of the physical tests made by Weis, certainly lend no support to the contention of Cloetta that the potent constituent of Digalen is identical with digitoxin, but, on the contrary, they show conclusively that the two substances differ widely in many essentials, and the continued claim of the manufacturers that the “amorphous digitoxin” said to be contained in Digalen is the same as digitoxin, or that it is the most active glucosid of digitalis, can be considered only as misleading, and therefore in conflict with the rules of the Council.
CONSTANCY OF COMPOSITION AND ACIDITY
The manufacturers of Digalen continue to claim that it is of constant and uniform activity,[32] and they imply this even when they do not state it in those words; for example, a substance cannot be considered reliable if it is variable in activity. “Digalen is Absolutely Reliable. It is Standardized and consequently always uniform. It does not produce gastric disturbances.”
That the foregoing is absolutely untrue can be shown abundantly. Hale[33] found digalen not to be uniformly stable; Weis found very different degrees of activity for Digalen in the liquid and tablet forms, the tablets being but one-third as active as the liquid, and the referee found very great variations in the activity of different specimens of Digalen, one specimen being almost inert. The results obtained by Miller show that Digalen is sometimes very slightly active, or not at all so.
The foregoing citations show conclusively that Digalen is not of uniform activity. When reliability is claimed for Digalen in contrast to the known variability of digitalis, it must be considered as tantamount to the claim that Digalen is not subject to such variability and it must be held that the manufacturers make misleading statements when they assert that Digalen is absolutely reliable.