Author: ["Jonathan A. Foster","Marc-Oliver M. Piepenbrock","Gareth O. Lloyd","Nigel Clarke","Judith A. K. Howard","Jonathan W. Steed"]
CITE.CC academic search helps you expand the influence of your papers.
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. Supramolecular gels based on small-molecule gelators have been shown to be effective media for the growth of organic crystals, including pharmaceutical compounds. Moreover, the gel-to-sol transition can be triggered by molecular recognition with anions, thereby enabling facile recovery of the crystals.Cite this article
Foster, J., Piepenbrock, MO., Lloyd, G. et al. Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth. Nature Chem 2, 1037–1043 (2010). https://doi.org/10.1038/nchem.859 