Quantitative determination and identification of pharmaceuticals by means of Gran's potentiomentric method.

A method is proposed both for the quantitative determination and identification of pharmaceuticals, based on the data of a single pH-metric titration. As a new identification criterion the pK-value of the pharmaceutical is proposed. The latter is conveniently determined using the Gran's graphical method. A new equation is derived for the data treatment of very weak bases, where the Gran's original method can not be applied directly. The proposed method is applied with determination and the identification of many pharmaceuticals weak and very weak acids and bases.