Pharmaceutical co-crystals - a review

Abstract

Co-crystallization alters the molecular interactions and composition of pharmaceutical materials, and is considered better alternatives to optimize drug properties. Co-crystals consists of API and a stoichiometric amount of a pharmaceutically acceptable co-crystal former. Pharmaceutical co-crystals are nonionic supramolecular complexes and can be used to address physical property issues such as solubility, stability and bioavailability in pharmaceutical development without changing the chemical composition of the API. Co-crystals can be constructed through several types of interaction, including hydrogen bonding, pi-stacking, and van der Waals forces. Co-crystals High Throughput provides information on relationship between formation and chemical structure of the API and conformer. Factors affecting co-crystal stability are reported and a co-crystal is only expected to form if it is thermodynamically more stable than the crystals of its components. Phase transformations induced during processing/storage affects the mechanisms of conversion of crystalline drugs to co-crystals. Pharmaceutical co-crystals could play a major part in the future of API formulation and can be employed for chiral resolution.