Preparative liquid chromatography in the field of X-ray contrast agents

The use of preparative liquid chromatography (LC) for the effective purification of potential X-ray contrast agents or intermediates is described. Pure products in grams to kilogram quantities have been obtained by reversed-phase preparative LC of highly water-soluble non-ionic compounds, a weak aliphatic carboxylic acid and an isophthalic acid derivative. The mobile phases used were mixtures of methanol-water alone or with the addition of ammonium acetate buffers, tetrabutylammonium chloride and phosphate buffer.