Development of an industrial high throughput co-crystal screening workflow
Jacob Danks Pharmaron UK
One of the challenges faced by the pharmaceutical industry in the development of APIs (active pharmaceutical ingredients) is poor biorelevant solubility, which can lead to low bioavailability and hence affect the efficacy of the drug. 1 Typically, formation of a salt between the API molecule and a counterion is used as a method of improving the solubility, 2 however in cases where there is no ionisable functional group on the molecule, or salt formation is unsuccessful, co-crystal formation can be utilised. 3 A co-crystal is defined as a single phase solid where two or more different components are present, generally in a stoichiometric ratio, and is not a solvate or simple salt. 4 High throughput co-crystallisation experiments have recently begun development, typically centred around a multi-well plate, much like those employed in polymorph and salt screens. 5 However progress has been hindered by the number of variables associated with cocrystal formation, and so far there has been little attention paid to considerations associated with cocrystal screening in an industrial setting. 6 Through this investigation, a variety of high throughput co-crystallisation methods were performed on model co-crystal systems with carbamazepine, including evaporative crystallisation, resonant acoustic mixing and slurry crystallisation. Both the effectiveness of each co-crystallisation method and the feasibility of implementing it into a screening workflow based on key industrial requirements (e.g. material quantity and time), alongside its ability to be scaled up to enable further characterisation, were considered in the design of the workflow. The comparison of these methods led to the outlining of a high throughput co-crystal screening workflow that was then demonstrated on sulfasalazine, an example of a BCS Class IV API. 7 References
1. K. T. Savjani, A. K. Gajjar and J. K. Savjani, ISRN Pharmaceutics, 2012, 2012, 1–10. 2. D. Gupta, D. Bhatia, V. Dave, V. Sutariya and S. Varghese Gupta, Molecules, 2018, 23. 3. S. S. Buddhadev and K. C. Garala, Proceedings, 2020, 62, 14. 4. S. Aitipamula et al, Crystal Growth & Design, 2012, 12, 2147–2152.
5. T. Kojima, S. Tsutsumi, K. Yamamoto, Y. Ikeda and T. Moriwaki, International Journal of Pharmaceutics, 2010, 399, 52-59. 6. V. Luu, J. Jona, M. K. Stanton, M. L. Peterson, H. G. Morrison, K. Nagapudi and H. Tan, International Journal of Pharmaceutics, 2013, 441, 356-364. 7. S. Clarysse, J. Brouwers, J. Tack, P. Annaert and P. Augustijns, European Journal of Pharmaceutical Sciences, 2011, 43, 260–269.
© The Author(s), 2023
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