Chromatographic determination of high-molecular weight impurities in amoxicillin.

The separation of high molecular weight impurities in amoxicillin has been examined by three methods of gel filtration chromatography (GFC) and reversed phase liquid chromatography (RPLC). Specificity of GFC was checked by applying the method for the determination of amoxicillin and its related impurities and linking of GFC and RPLC. The result shows that for the determination of polymers the gel filtration chromatography is a rather simple separation mode as compared to RPLC. Regarding the three gel filtration chromatographic methods, the separation on the Superdex peptide column is advantageous over other methods of determining amoxicillin polymers.