Instability of Stilbamidine in Aqueous Solution

Abstract

THE changes which stilbamidine and related compounds undergo in solution on exposure to the action of light have received considerable attention in the last two years, and several publications dealing with the subject have appeared in the literature, from which it seems that the methods of approach have been biological and physical rather than chemical. Fulton and Yorke¹, Fulton², Barber, Slack and Wien³ and Goodwin⁴ have contributed to the elucidation of the changes which occur, and the present position may be summed up briefly as follows. Stilbamidine and, to a rather less extent, its monomethyl derivative, undergo profound chemical change under the action of light, which change is accompanied by a large increase in toxicity, loss of therapeutic activity and disappearance of those properties (characteristic light absorption and capacity for reacting with bromine and permanganate) which are attributable to the ethylenic linkage. The 4:4′-diamidino derivatives of dimethyl stilbene, tolane, diphenyl ethane and diphenoxy pentane undergo little or no change on exposure to light.