Application of the threshold of toxicological concern concept when applied to pharmaceutical manufacturing operations intended for short-term clinical trials.

In the manufacture of pharmaceuticals, if a multiproduct facility shares equipment amongst drug substances/products it is incumbent upon the manufacturer to demonstrate removal of the pharmaceutical through a robust cleaning validation/verification program. Removal must be to below limits considered acceptable from a quality and toxicological perspective. In order to address the toxicological concerns, an acceptable daily exposure (ADE) was developed which is the "dose that is unlikely to cause an adverse effect if...exposed, by any route...at or below this dose every day for a lifetime" (ISPE, 2010). For compounds in development, defaulted ADEs were proposed by Dolan et al. (2005) and adopted by the International Society of Pharmaceutical Engineers (ISPE) as conservative cutoffs for compounds with limited data. In Phase 1 clinical trials, exposure is typically short-term (single dose or repeated doses for ≤30 days) compared to the chronic doses used to derive ADE and defaulted ADEs. An analysis of publicly available databases for toxicological and pharmacological effects supports the use of 10-fold higher defaulted values when the residual drug substance is in a developmental pharmaceutical intended for Phase 1 clinical trials (exposure ≤30 days).