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Angew Chem Int Ed Engl. 2016 Jul 25;55(31):8904-8. doi: 10.1002/anie.201602936. Epub 2016 Jun 07.

(19) F NMR Spectroscopy as a Highly Sensitive Method for the Direct Monitoring of Confined Crystallization within Nanoporous Materials.

Angewandte Chemie (International ed. in English)

Karol P Nartowski, Diksha Malhotra, Lucy E Hawarden, Juraj Sibik, Dinu Iuga, J Axel Zeitler, László Fábián, Yaroslav Z Khimyak

Affiliations

  1. School of Pharmacy, University of East Anglia, Norwich, UK.
  2. Department of Drug Form Technology, Faculty of Pharmacy, Wroclaw Medical University, ul. Borowska 211, 50-556, Wroclaw, Poland.
  3. Drug Product Science and Technology, Bristol-Myers Squibb, Reeds Lane, Moreton, Merseyside, CH46 1QW, UK.
  4. Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK.
  5. F. Hoffmann-La Roche A.?G., 4070, Basel, Switzerland.
  6. UK 850?MHz Solid-State NMR Facility, Department of Physics, Millburn House, University of Warwick, Coventry, CV4 7AL, UK.
  7. School of Pharmacy, University of East Anglia, Norwich, UK. [email protected].

PMID: 27272008 DOI: 10.1002/anie.201602936

Abstract

The introduction of fluorine into the structure of pharmaceuticals has been an effective strategy for tuning their pharmacodynamic properties, with more than 40 new drugs entering the market in the last 15 years. In this context, (19) F NMR spectroscopy can be viewed as a useful method for investigating the host-guest chemistry of pharmaceuticals in nanosized drug-delivery systems. Although the interest in confined crystallization, nanosized devices, and porous catalysts is gradually increasing, understanding of the complex phase behavior of organic molecules confined within nanochambers or nanoreactors is still lacking. Using (19) F magic-angle-spinning NMR spectroscopy, we obtained detailed mechanistic insight into the crystallization of flufenamic acid (FFA) in a confined environment of mesoporous silica materials with different pore diameters (3.2-29 nm), providing direct experimental evidence for the formation of a molecular-liquid-like layer besides crystalline confined FFA form I.

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Keywords: drug delivery; flufenamic acid; mesoporous silica; nanocrystals; solid-state NMR spectroscopy

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