Application of Gran's potentiometric method in pharmaceutical analysis.

Because of weak acid-base properties, many pharmaceuticals cannot be determined by the convenient neutralization titrimetric method. It is shown that such substances can be precisely analyzed by applying the graphic pH-potentiometric method of Gran. Some water-soluble and insoluble pharmaceuticals, which usually are analyzed in nonaqueous solvents, have been determined precisely in water solution by this method. The latter is also applied successfully to the analysis of mixtures and impurities in pharmaceuticals.