Comparison of the bromureide sedative-hypnotic drugs, bromvaletone (bromisoval) and carbromal, and their chloro analogues in mice.

1. The central depressant effects of bromvaletone, carbromal and six non-bromo analogues were compared in mice. 2. The chloro analogues of bromvaletone and carbromal were slightly less potent as central depressant agents than the bromo compounds. 3. The chloro analogue of bromvaletone had the greatest margin between central depressant and lethal doses. 4. Lipophilicity (octanol-water partition coefficient) did not provide a unifying relationship for potency within this group of eight acylureas. However, within each of the two subsets of compounds, a linear relationship was found between relative potency and lipophilicity.