Purity of antidotal oxime HI-6 DMS as an active pharmaceutical ingredient for auto-injectors and infusions

Abstract

As reactivators of inhibited acetylcholinesterase, oximes are essential antidotes in poisoning by organophosphorus compounds. Due to its superior efficacy in cases of soman, cyclosarin, and sarin poisoning, the oxime HI-6 represents a promising option for an active pharmaceutical ingredient (API) in the further development of antidote therapy for nerve agent poisoning. Developmental lots of HI-6 DMS (dimethanesulfonate) provided by different manufacturers were examined with respect to their content and purity with a view to their future use as an API. There are distinct differences in the HI-6 content from three manufacturers. With respect to purity, gradual differences arise with the known synthetic by-products as well as with unknown accompanying compounds. It became apparent that in the case of a modified synthesis using protective groups, the proportion of some synthesis by-products decreases considerably. With one exception, they are thus below the reporting threshold for API in accordance with pertinent regulatory guidelines. In HI-6, an unknown impurity always occurs, whose percentage necessitates identification due to regulations. This unknown impurity, which has not been described so far, could be identified as an isomer. These findings supply data required for the description of pharmaceutical quality in accordance with module 3 of a Common Technical Document (CTD). They thus contribute to the marketing authorization of this substance as an API for auto-injectors and infusions.