Determination of the partition coefficient and acid dissociation constants of iodochlorhydroxyquin by an improved partition method

A simple and precise method for determining partition coefficients was developed utilizing a disposable injector. The method was used to determine the partition ratio of iodochlorhydroxyquin between n-decane and phosphate-buffered saline, pH 7.4. The partition ratio was found to be 1750 with a coefficient of variation of 3%. Moreover, it was found that iodochlorhydroxyquin did not associate in n-decane at a concentration less than 1 X 10(-3) M. The acid dissociation constants and the partition coefficient of the undissociated species were determined. These values corresponded well with the values obtained from spectrophotometric methods.