Applying hot-stage microscopy to co-crystal screening: A study of nicotinamide with seven active pharmaceutical ingredients.
AuthorBerry, David J.
Seaton, Colin C.
MetadataShow full item record
AbstractCo-crystal screening is routinely undertaken using high-throughput solution growth. We report a low- to medium throughput approach, encompassing both a melt and solution crystallization step as a route to the identification of co-crystals. Prior to solution studies, a melt growth step was included utilizing the Kofler mixed fusion method. This method allowed elucidation of the thermodynamic landscape within the binary phase diagram and was found to increase overall screening efficiency. The pharmaceutically acceptable adduct nicotinamide was selected and screened against a small set of active pharmaceutical ingredients (APIs) (ibuprofen (both the racemic compound (R/S) and S-enantiomer), fenbufen, flurbiprofen (R/S), ketoprofen (R/S), paracetamol, piracetam, and salicylic acid) as part of a larger systematic study of synthon stability. From the screen, three new co-crystal systems have been identified (ibuprofen (R/S and S) and salicylic acid) and their crystal structures determined. Because of poor crystal growth synchrotron radiation was required for structure solution of the S-ibuprofen nicotinamide co-crystal. Two further potential systems have also been discovered (fenbufen and flurbiprofen), but crystals suitable for structure determination have yet to be obtained. A greater ability to control crystallization kinetics is required to yield phase-pure single-crystalline material for full verification of this crystal engineering strategy.
CitationBerry, D. J., Seaton, C. C., Clegg, W., Harrington, R. W., Coles, S. J., Horton, P. N., Hursthouse, M. B., Storey, R., Jones, W., Friščić, T. and Blagden, N. (2008). Applying hot-stage microscopy to co-crystal screening: A study of nicotinamide with seven active pharmaceutical ingredients. Crystal growth & design, Vol. 8, No. 5, pp. 1697-1712.
Link to publisher’s versionhttp://dx.doi.org/10.1021/cg800035w
Showing items related by title, author, creator and subject.
Characterization and Biocompatibility Study of Nematic and Cholesteryl Liquid Crystals.Soon, Chin Fhong; Youseffi, Mansour; Blagden, Nicholas; Berends, Rebecca F.; Batista Lobo, Samira; Javid, Farideh A.; Denyer, Morgan C.T. (2009)Intensive research in bio-engineering has been conducted in the search for flexible biomaterials that could support cell growth and cells attachment. Flexible synthetic materials that support cell growth without the aid of synthetic extracellular matrix proteins are still rare. Cholesteryl liquid crystal containing cholesteryl moieties may have suitable biological affinity. Human keratinocytes (HaCat) were cultured with a nematic liquid crystal and three cholesteryl liquid crystals of different formulation. Subsequently, the trypan blue dye exclusion assay was used to determine cell viability in the liquid crystals. The two classes of liquid crystal were characterized by Differential Scanning Calorimeter (DSC) and polarizing microscope (POM) to understand the nature of the interface material. The cell viability study in medium containing liquid crystals verified that liquid crystals had no effects on cell viability. However, only the surface of cholesteryl liquid crystal has shown affinity to HaCat cells. In addition, cells continued to proliferate in the presence of liquid crystals without a change of medium for eight days. No sign of exothermic and endothermic activities at 370C were observed from the DSC test results for the three samples. Biological and mechanical test result of the cholesteryl liquid crystals has shown that cholesteryl liquid crystals are non toxic and support cell attachment without extracellular matrix protein at very low elasticity.
Building up co-crystals: structural motif consistencies across families of co-crystalsSeaton, Colin C. (MDPI, 2021-01)The creation of co-crystals as a route to creating new pharmaceutical phases with modified or defined physicochemical properties is an area of intense research. Much of the current research has focused on creating new phases for numerous active pharmaceutical ingredients (APIs) to alter physical properties such as low solubilities, enhancing processability or stability. Such studies have identified suitable co-formers and common bonding motifs to aid with the design of new co-crystals but understanding how the changes in the molecular structure of the components are reflected in the packing and resulting properties is still lacking. This lack of insight means that the design and growth of new co-crystals is still a largely empirical process with co-formers selected and then attempts to grow the different materials undertaken to evaluate the resulting properties. This work will report on the results of a combination of crystal structure database analysis with computational chemistry studies to identify what structural features are retained across a selection of families of co-crystals with common components. The competition between different potential hydrogen bonding motifs was evaluated using ab initio quantum mechanical calculations and this was related to the commonality in the packing motifs when observed. It is found while the stronger local bonding motifs are often retained within systems, the balance of weaker long-range packing forces gives rise to many subtle shifts in packing leading to greater challenges in the prediction of final crystal structures.
Current directions in co-crystal growth.Blagden, Nicholas; Berry, David J.; Parkin, A.; Javed, Hafsa S.; Ibrahim, Asim; Gavan, Pauline T.; De Matos, Luciana L.; Seaton, Colin C. (2008)In this feature article we will focus on the issues relating to the crystal growth of co-crystals, with a particular emphasis on drug development. The initial focus of this perspective is on the relevant literature examples that may be able to inform our understanding with regards co-crystal crystallisation and the allied supramolecular concepts. The second part of this perspective contains selected examples from our own work, which add to the literature perspective. Topics include; nucleation templates, in situ synchrotron XRD studies, solid-state synthesis through mixing and screening strategies.