ABSTRACT
A potentiometric method for the determination of impurities in pharmaceuticals with acid-base behaviour is proposed. Based on proton balance condition, appropriate equations for the treatment of the data are derived. The latter in combination with Gran's equations allow the determination of acid-base impurities in pharmaceuticals--weak protolytes. The proposed method is quick, accurate and precise. It is suitable both for technical control and for analyses according to the pharmacopoeias.
Subject(s)
Drug Contamination , Acids/analysis , Alkalies/analysis , Chemical Phenomena , Chemistry , Methods , Pharmaceutical Preparations/analysis , PotentiometryABSTRACT
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.
