The FDA finalized new guidance establishing co-crystals as a drug product intermediate.

Sponsors of NDAs and ANDAs for products containing a co-crystal form must submit data proving the active pharmaceutical ingredient dissociates from the co-crystals before reaching the site of pharmacological activity, the agency said.

Pharmaceutical co-crystals — usually composed of the drug’s API and co-crystal formers, or coformers — can be adapted to improve bioavailability and stability as well as the processability of the APIs during the manufacturing process.

NDAs and ANDAs claiming to contain a co-crystal form should include evidence demonstrating both the coformers and the API are present in the unit cell, the agency said.