Analysis of Ions in Drugs (Part 5) Analysis of Organic Acid Counterions by Ion Exclusion Chromatography

Introduction

The physicochemical and pharmacokinetic properties of active pharmaceutical ingredients change depending on the counterion used, and during drug development various counterions are tested to select the optimum salt. Residual inorganic impurities from catalysts or ions used during synthesis can also affect product solubility and stability, so it is extremely important that ion impurities are identified. Application News No. L457 described an example analysis of chloride, formic acid, acetic acid, and trifluoroacetic acid ions present in drugs using ion chromatography. As mentioned above, drugs can contain multiple different counterions and it is sometimes difficult to separate completely the peaks of these ions using ion chromatography. We describe an example analysis that uses ion exclusion chromatography to increase separation selectivity for formic acid, acetic acid, fumaric acid, and maleic acid, which are organic acids frequently used for drug counterions.

April 14, 2016 GMT