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Co-crystalsand their advantagesfor APIs with challenging properties


*Corresponding author
Carl-Bosch-Strasse 38
67056 Ludwigshafen, Germany


Active pharmaceutical ingredients (APIs) often have disadvantageous solid state properties. These properties depend on the solid state and can be modified by changing the solid form (polymorphs, solvates, hydrates, salts and co-crystals). The co-crystal concept can be applied to the vast majority of solid APIs and allows, in contrast to all other solid-state modifications, to increase in many cases the dissolution-rate even for non-charged APIs without compromising on the thermodynamic stability.
In this paper new co-crystals of APIs with improved properties regarding physical stability and bioavailability are presented. It is discussed that the new solid state properties could lead to a second generation drug product with easier formulation, lower limitations for storage, lower amount of API per drug product with all its improvements regarding safety and costs.



Screening a vast number of chemical compounds is the first part of drug discovery. After an active pharmaceutical ingredient (API) with good biological activity, toxicology profile etc. is found, formulation is the next step to make a drug product. As further optimisation of the compounds concerning their biological performance using in-vitro enzyme activity leads to more and ... ...