A method for measuring the activity of compounds with an activity like vitamin K against indirect anticoagulants in rats.

A method for the estimation of the activity of compounds like vitamin K using rats treated with an indirect anticoagulant is described. The assay measured the speed of onset and magnitude of the antidotal effect. Under the conditions employed, only vitamin K(1) produced a significant response. Vitamin K(3) and its water-soluble derivatives were inactive. Both the magnitude and the speed of onset of the antidotal effect of vitamin K(1) were found to depend on the extent to which it was in solution. The assay gave results of fair accuracy and reproducibility, which permitted a full statistical analysis and provided an estimate of error.