Acute Toxicity of Trypan Blue,Gentian Violet and Brilliant Green. ∗

Abstract

Difficulties encountered in administering sufficient amounts of the usual chaulmoogra oil derivatives uniformly to effect a cure in leprous subjects have led to the attempted application of other forms of therapy. Thus, recent clinical developments 1 , 2 again have aroused interest in the efficacy of certain non-chaulmoogry (Link Missing 1) drugs, synthetic dyes in particular, against leprosy. In the course of examining the possible antileprotic activity of certain such compounds by a standardized technique, 3 determination of their toxicity in the test animals was a necessary preliminary. As trypan blue, gentian violet, and brilliant green have been used in an empirical manner in the clinic before a critical pharmacological evaluation of their worth has been made, it is advisable to present the results of this toxicity study on experimental animals, before toxic doses may unavoidably be given to human leprous subjects. The intravenous dosage of these dyes, as reputedly used by Ryrie 1 and Ryles, 2 is within the possible lethal range as estimated from experimental animals. While these workers do not give the sources of the dyes used by them, nor their standards of purity, so that it cannot be judged whether or not their dyes are comparable in purity to those used by us, it is significant that Ryrie 1 admits the occurrence of dangerously severe acute toxic effects in his patients.

Previously reported toxicity data on these 3 dyes are so inadequate and variant that a recent encyclopedic work on chemotherapy 4 omits all reference to their toxicity. Discrepancies in some cases may be explained by variations in purity and by the use of old solutions. Photodynamic action is not a significant factor in the toxicity of these dyes as far as we could determine. We will later make a more extended report surveying the therapeutic effectiveness as well as the chronic and acute toxicity of these agents. Such a study is indicated in view of enthusiastic endorsement of dye therapy in leprosy on grounds that it is as good as treatment with hydnocarpus oil derivatives, safe, cheap and not unduly painful.