Synthesis and characterization of potential impurities of Ampicillin trihydrate

Abstract

The present research work narratesthe synthesis, origin and characterization of related substances of Ampicillin trihydrate Viz: Ampicillinyl-d-phenylglycine (Ph. Eur impurity E) & l-Ampicillin (Ph. Eur impurity B). The impurity Ampicillinyl-d-phenylglycine generates during the preparation of Ampicillin trihydrate, amidation may occur with carboxylic acid of Ampicillin with d-phenylglycine to give Ampicillinyl-dphenylglycine, the impurity l-Ampicillin may arise due to the presence of traces l-phenylglycine methylester in d-phenylglycine methylester hydrochloride which may result in the formation of l-Ampicllin. A facile synthetic process for these impurities was developed from the commercially available raw materials.