Solid state properties – co-crystals
Co-crystals are materials in which the API and another material pack into a set crystal structure. In effect, hydrate and solvates are co-crystals, but generally here we consider other pharmaceutically acceptable additives that can be given with the API with safety. The additive will usually be pharmacologically inactive, but there is potential for two actives to for a co-crystal.
The vast majority of APIs exist as weak acids or weak bases and for these a usual starting point would be salt formation, however, some APIs are none ionisable and these cannot form salts. In such circumstances co-crystals provide a means by which the physic-chemcial properties of the API can be adapted to enhance its developability as a medicine.
There is rather less predictability about the properties of co-crystals at this time, making for interesting intellectual property considerations.
Consultancy is available for
• selecting the most appropriate co-crystal screening strategy
• outsource company selection and management
• data interpretation
The goal is to fit the physical form strategy into the overall product development strategy to get the product of suitable quality in the shortest possible development time.
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