Cocrystallisation by freeze-drying: preparation of novel multicomponent crystal forms

We demonstrate the utility of freeze-drying as a general method for cocrystal synthesis as well as for the preparation of new solid forms of drug-coformer cocrystal systems. Using this approach, several previously reported cocrystal phases containing pharmaceutical compounds were reproduced. In addi...

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Bibliographic Details
Main Authors: Eddleston, Mark D. (Author), Patel, Bhavnita (Author), Day, Graeme M. (Author), Jones, William (Author)
Format: Article
Language:English
Published: 2013-10-02.
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Summary:We demonstrate the utility of freeze-drying as a general method for cocrystal synthesis as well as for the preparation of new solid forms of drug-coformer cocrystal systems. Using this approach, several previously reported cocrystal phases containing pharmaceutical compounds were reproduced. In addition, a novel solid solution of caffeine and theophylline and a potential new crystal form of the theophylline:oxalic acid cocrystal were prepared. It is shown that cocrystal formation proceeds via an amorphous phase which is generated as solvent sublimes during the freeze-drying process. The application of freeze drying to cocrystallisation is advantageous as it avoids problems caused by differences in the solubilities of coformers, and is a technique which is widely used to prepare products on an industrial scale, such as in the manufacture of pharmaceutical dosage forms