Abstract
Single crystals of the N,N-dimethylformamide (DMF) solvate (1:1) of flurbiprofen (FBP) were grown for the first time and characterised by X-ray diffraction, IR spectrophotometry, DSC and solution calorimetric methods. The structure may be characterised as a layer-structure, where DMF double-sheets are arranged between FBP double-sheets. The FBP and DMF molecules are linked to each other by a hydrogen bond, which is formed between the hydroxyl group of FBP and the carbonyl group of DMF. The conformation of FBP molecules in the DMF solvate differs from analogous enantiomers in the unsolvated form. The differences are discussed from the point of view of the influence of the nature of the solvent on selective crystallisation of the enantiomers. A peculiarity of the solvate is its low melting point, 37.3±0.2°C, with respect to the unsolvated phase, 113.5±0.2°C. Based on solution enthalpies of the solvated and unsolvated phases dissolved in DMF, the difference in crystal lattice energies, 9.8 kJ mol-1, was calculated and the difference in entropies, 33 J mol-1 K-1 estimated. A possible mechanism explaining the low melting point of the solvate is discussed.
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References
C. D. Bevan and R. S. Lloyd, Anal. Chem., 72 (2000) 1781.
J. Hadgraft, J. Plessis and C. Goosen, Int. J. Pharm., 207 (2000) 31.
J. O. Henck and M. Kuhnert-Brandstätter, J. Pharm. Sci., 88 (1999) 103.
F. Lacoulonche, A. Chauvet and J. Masse, Int. J. Pharm., 153 (1997) 167.
K. Harata, K. Uekama, M. Otagiri and F. Hirayama, J. Incl. Phen., 1 (1984) 279.
K. Harata, K. Uekama, T. Imai, F. Hirayama and M. Otagiri, J. Incl. Phen., 6 (1988) 443.
K. Uekama, F. Hirayama, T. Imai, M. Otagiri and K. Harata, Chem. Pharm. Bull., 31 (1983) 3363.
K. Uekama, T. Imai, F. Hirayama, M. Otagiri and K. Harata, Chem. Pharm. Bull., 32 (1984) 1662.
K. Harata, F. Hirayama, T. Imai, K. Uekama and M. Otagiri, Chem. Lett., (1984) 1549.
J. K. Guillory, Generation of polymorphs, hydrates, solvates, and amorphous solids. In Brittain H. G., Ed. Polymorphism in Pharmaceutical Solids. New York: Marcel Dekker Inc. 1999, p. 183.
J. D. Cox and and G. Pilcher, Thermochemistry of organic and organometallic compounds, London, Academic Press 1970, p. 643.
P. McArdle, J. Appl. Cryst., 26 (1993) 752.
Enraf-Nonius. 1989. CAD-4 Software. Version 5.0. Enraf-Nonius, Delft, The Netherlands
G. M. Sheldrick, SHELXS-97 Program for Crystal Structures Solution. University of Göttingen, Göttingen 1997.
G. M. Sheldrick, SHELXL-97 Program for the Refinement of Crystal Structures. University of Göttingen, Göttingen 1997.
J. L. Flippen and R. D. Gilardi, Acta Cryst., B31 (1975) 926.
P. Hobza, H. L. Selzle and E. W. Schlag, J. Phys. Chem., 97 (1993) 3937.
P. Hobza, H. L. Selzle and E. W. Schlag, J. Am. Chem. Soc., 116 (1994) 3500.
E. L. Eliel, S. H. Wilen and L. N. Mander, Stereochemistry of organic compounds; John Wiley &; Sons, New York 1994.
Z. J. Li and D. J. W. Grant, J. Pharm. Sci., 86 (1997) 1073.
G. L. Perlovich, L. Kr. Hansen and A. Bauer-Brandl, J. Therm. Anal. Cal., 66 (2001) 699.
D. J. W. Grant and T. Higuchi, Solubility behavior of organic compounds. New York, Wiley, 1990.
A. Gavezzotti and G. Filippini, Energetic aspects of crystal packing: Experimental and computer simulations. In Gavezzotti A. Ed., Theoretical aspects and computer modelling of the molecular solid state. New York, John Wiley &; Sons 1997, pp. 61-97.
C. H. Gu and D. J. W. Grant, J. Pharm. Sci., 90 (2001) 1277.
J. L. Pascual-Ahuir and E. Silla, J. Comp. Chem., 11 (1990) 1047.
A. I. Kitaigorodsky, The molecular crystals. M. Nauka, 1971.
Z. J. Li, W. H. Ojala and D. J. W. Grant, J. Pharm. Sci., 90 (2001) 1523.
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Perlovich, G.L., Hansen, L.K. & Bauer-Brandl, A. Solvates with anomalous low melting points. Journal of Thermal Analysis and Calorimetry 73, 715–725 (2003). https://doi.org/10.1023/A:1025857810703
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DOI: https://doi.org/10.1023/A:1025857810703