Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth

Foster, JA; Piepenbrock, MOM; Lloyd, GO; Clarke, N; Howard, JAK; Steed, JW

Abstract

We describe the use of low-molecular-weight supramolecular gels as media for the growth of molecular crystals. Growth of a range of crystals of organic compounds, including pharmaceuticals, was achieved in bis(urea) gels. Low-molecular-weight supramolecular gelators allow access to an unlimited range of solvent systems, in contrast to conventional aqueous gels such as gelatin and agarose. A detailed study of carbamazepine crystal growth in four different bis(urea) gelators, including a metallogelator, is reported. The crystallization of a range of other drug substances, namely sparfloxacin, piroxicam, theophylline, caffeine, ibuprofen, acetaminophen (paracetamol), sulindac and indomethacin, was also achieved in supramolecular gel media without co-crystal formation. In many cases, crystals can be conveniently recovered from the gels by using supramolecular anion-triggered gel dissolution; however, crystals of substances that themselves bind to anions are dissolved by them. Overall, supramolecular gel-phase crystallization offers an extremely versatile new tool in pharmaceutical polymorph screening.

Citation

Foster, J., Piepenbrock, M., Lloyd, G., Clarke, N., Howard, J., & Steed, J. (2010). Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth. Nature Chemistry, 2(12), 1037-1043. https://doi.org/10.1038/nchem.859

• Journal Article Type: Article
• Publication Date: Dec 1, 2010
• Deposit Date: Feb 6, 2012
• Publicly Available Date: Mar 27, 2013
• Journal: Nature Chemistry
• Print ISSN: 1755-4330
• Electronic ISSN: 1755-4349
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 2
• Issue: 12
• Pages: 1037-1043
• DOI: https://doi.org/10.1038/nchem.859
• Keywords: Materials chemistry, Supramolecular chemistry.
• Public URL: https://durham-repository.worktribe.com/output/1506493