Preclinical Toxicology of New Drugs

A series of preclinical safety evaluations of two drugs under development by the USAMRDC, WR 238605, succinate, an antimalarial, and pyridostigmine bromide, a reversible acetylcholinesterase inhibitor, were conducted in experimental animals. In addition, the effects of pyridostigmine on the ultrastructure of the neuromuscular junction junction were evaluated. WR 238605, succinate was toxic to the hematopoietic system and demonstrated both cumulative toxicity and slow reversal. Pyridostigmine was an effective inhibitor of acetylcholinesterase after oral administration, with toxic effects mainly on the gastrointestinal tract.