A Rapid Method for the Determination of Distribution Coefficient of Bases for Biological Purposes.

Abstract

To an aq. soln. of the pure hydrochloride, NaOH is added by an automatictitrator operating as a pH-stat until the pH at which approx. 1/5of the hydrochloride is converted to the free base is obtained. Whenthe pH is between 6 and 10 the quantity of alkali added is equiv.to the amt. of free base liberated. An org. solvent, immiscible withwater, is then added. As some of the base dissolves in the org. layer,more alkali is required to maintain the pH at the original value.This amt. is therefore added by the instrument. When equil. is obtainedthe quantity of alkali added is equiv. to the total quantity of freebase present in both the aq. and the org. layers. It is possibleto calc. the distribution coeff. from the amt. of alkali added beforeand after the addn. of the org. solvent. [on SciFinder(R)]