Cefdinir lactone is used in the pharmaceutical industry for the manufacture of cefdinir and in research involving the development and optimization of cephalosporin antibiotics.

Cefdinir lactone does not have a therapeutic purpose instead it is primarily used as a reference impurity standard for analytical testing and quality control of cefdinir drug substances and formulations.

Cefdinir lactone is a cyclic degradation product or process-related impurity associated with the cephalosporin antibiotic cefdinir. It is formed by intramolecular cyclization of cefdinir under certain conditions.