title: The determination of oxalic acid, oxamic acid, and oxamide in a drug substance by ion-exclusion chromatography.
abstract: Oxalic acid, oxamic acid and oxamide are potential impurities in some active pharmaceutical ingredients (API). The retention and separation of oxalic and oxamic acids are particularly challenging using conventional reversed-phase HPLC due to their high polarity. An ion-exclusion chromatography (IEC) method has been shown to provide good separation and sensitivity for the three oxalate-related impurities in a hydrophobic API matrix. The method uses a Dionex IonPac ICE-ASI column with 95/5 (v/v) 0.1% sulfuric acid/acetonitrile as the mobile phase and UV detection at 205 nm. Development and validation of this method are described.
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Lafayette, IN 47902, USA. yang_liu@lilly.com
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: B A
authors.initials: BA
authors.lastname: Olsen
authors.forename: M A
authors.initials: MA
authors.lastname: Nussbaum
mesh_terms: D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004340:Drug Contamination; D016014:Linear Models; D019815:Oxalic Acid / Q000032:analysis*; D010072:Oxamic Acid / Q000031:analogs & derivatives* / Q000032:analysis*; D019163:Reducing Agents / Q000032:analysis*; D012680:Sensitivity and Specificity
chemical_list: D019163:Reducing Agents; D019815:Oxalic Acid; D010072:Oxamic Acid; C008728:oxamide