Application Note: USP Modernization Initiative: Ionic Impurities in Drug Substances by Ion Chromatography
28 November 2018

Chloride and sulfate are common impurities present in drug substances and drug products. Limit tests are based on turbidity and/or visual comparison methods as per USP general chapter. These methods lack specificity and data integrity. One of the main goals of the USP monograph modernization initiative is to replace non-specific methods with highly selective and sensitive instrumental analysis methods. We propose a selective and sensitive ion chromatography (IC) method for chloride and sulfate detection in drug substances, potassium carbonate and potassium bicarbonate. The proposed method can be used for other anionic impurities, such as fluoride, bromide, nitrate and nitrate, if needed.