Pharmaceutical Co-crystals – a review

The design and synthesis of pharmaceutical co-crystals have received great interest in recent years. co-crystallization of drug substances offer a tremendous opportunity for the development of new drug products with superior physical and pharmacological properties such as solubility, stability, hygroscopicity, dissolution rates, and bioavailability. This short review summarizes this highly topical field, covering why the topic is of interest in pharmaceutical formulation, the definitions and practical scope of co-crystals, co-crystal preparation, and characterization, comparison of different (traditional and novel) methods for co-crystal formation, and implications for regulatory control and intellectual property protection. Traditionally, co-crystal can be prepared by solvent evaporation method, grinding, and slurry method, but, every method has limitations for certain conditions. The current trend for co-crystal formation uses sophisticated methods such as the hot-melt extru­sion method, spray drying method, supercritical fluid technology, and the newest, and laser irradiation method. The development of new method is not only to overcome the limitation of traditional co-crystallization methods but also to generate a simpler step and continuous process for the production of co-crystal products. This article gives a brief explanation of each method that can be used to generate pharmaceutical co-crystals.