The Toxicity and Balantidicidal Action of “Di-Hydranol” in Guinea Pigs. ∗

Abstract

The frequent natural infestation of guinea pigs with such an easily observed intestinal parasite as Balantidium coli offers an excellent opportunity for a carefully controlled study of the parasiticidal action in vivo of new drugs of possible use in this regard. With proper toxicity studies of the same drugs in healthy uninfected guinea pigs, one may thus obtain quantitative data of considerable value in estimating the relative chemotherapeutic indices of a series of compounds, and thus the more readily estimate their worth for clinical trial in humans. Sweeney 1 has already nicely demonstrated the possibilities of this technique. We determined to use this method as an adjunct to our general investigation of the chemotherapy of amebiasis, especially to assist in determining whether or not a compound is worth the time and expense of study in natural or induced amebic infestation in monkeys or other animals.

Such studies of toxicity and experimental activity, together with quantitative data on the rate of secretion, we consider absolutely necessary before one may be justified in attempting the clinical evaluation of a new drug in human therapy. 2 New drugs are continually being offered for clinical evaluation in amebiasis and we are amazed that so many come to clinical trial without reference to quantitative data either on toxicity and therapeutic activity in experimental animals or rate of excretion in normal humans. Thus Faust has recently reported 3 on the clinical evaluation of 2-4 dihydroxy-phenyln-heptane (“di-hydranol”) in humans before the publication of a proper evaluation of the relationship between the toxic and parasiticidal dosage of this compound as it may be estimated in experimental animals without involving danger to human patients. It is to supply this essential information that the present report is made.