Rosiglitazone Maleate. Because there is no existing USP monograph for this drug substance, a new monograph based on validated methods ofanalysis is proposed. The liquid chromatographic procedures in the test for Organic Impurities and in the Assay, although different, are both basedon analyses performed with the Waters Symmetry C18 brand of L1 column. The typical retention times for rosiglitazone are about 5.3 min in theAssay and about 23 min in the test for Organic Impurities. The liquid chromatographic procedure in the test for Content of Maleic Acid is based onanalyses performed with the Waters Spherisorb SAXbrand of L14 column. The typical retention time for maleic acid is about 2.4 min.