Pharmaceutical co-crystals-an opportunity for drug product enhancement.

By maximizing our understanding of materials and the relative importance of interactions on all levels (i.e., molecular, particle, powder, product), we can improve the manufacture of drug dosage forms and thus meet target specifications for mechanical durability, stability and biopharmaceutical performance. Pharmaceutical co-crystals are the latest material being explored in order to enhance drug properties using this bottom-up approach. In this review we provide a general introduction to pharmaceutical co-crystals. We also address common aspects of co-crystal formation, discuss screening strategies and outline methodologies for co-crystal functionality. Pharmaceutical co-crystals that have a distinct solid phase possess a unique set of properties, thus co-crystal formation can act as an advantageous alternative to other solid-state modification techniques. More research is needed in order to scale up co-crystal systems and implement manufacturing of final dosage forms on large scale.