Variation of commercial diisopropyl fluorophosphate preparations in toxicological studies

The variation of three diisopropyl fluorophosphate (DFP) lots obtained from two sources was investigated. The effects of different lots of DFP on body weight, mortality, and brain acetylcholinesterase activity in rats varied significantly. The in vitro effects of these DFP preparations on brain acetylcholinesterase activity also were markedly different. It appears that different commercial preparations of DFP possess different potencies and that the same apparent doses of different DFP preparations will not produce the same effects upon any physiological system under study.