The selection of arylamidinourea antimalarials by their predicted physicochemical properties.

1 A small group of arylamidinoureas for which the predicted physicochemical properties were widely spaced and uncorrelated was selected for study.2 The antimalarial activity of each compound was measured against three species of plasmodium. Three corresponding regression equations were calculated relating the potency of each compound to its predicted physicochemical properties.3 The potency of further test compounds was forecast for each species, by using the corresponding regression equation. These forecasts were compared with the measured activity of the test compounds, and were better than would be expected by chance.4 It is suggested that only a few compounds in a series need be studied initially in order to derive regression equations with worthwhile predictive properties, if the compounds are selected according to appropriate criteria.