Pharmaceutical cocrystals: from serendipity to design to application.

The field of pharmaceutical cocrystals has reached a tipping point, particularly because cocrystals can improve the physicochemical properties of drugs without compromising their therapeutic benefit. Accounts of cocrystal investigations in the literature started in earnest in 2003 and patent applications soon followed. The frequency of both has steadily accelerated, demonstrating an enhanced understanding of the design, characterisation, and manufacture of cocrystals and heightened interest from industry. Indeed, there were four new product approvals from 2014 to 2017 and more are in the pipeline. Here, we review all marketed drug products that are based upon pharmaceutical cocrystal drug substances, starting with the first recorded example, Beta-Chlor® in 1963, with a particular emphasis on their discovery, rationale for use, and market impact.