Structures from powders: Diflorasone diacetate

Elisabetta Maccaroni, Giovanni Battista Giovenzana, Giovanni Palmisano, Daniela Botta, Paolo Volante, Norberto Masciocchi

Risultato della ricerca: Contributo su rivistaArticolo in rivistapeer review

Abstract

Diflorasone diacetate, a steroid anti-inflammatory drug (marketed as Diacort® or Florone® by Pfizer) and used in the treatment of skin disorders, can be prepared as anhydrous form, DD1 (as deposited in the US pharmacopoeia), or as a monohydrated phase, DDW. Heating the DDW form above 90 °C, a mixture of DD1 and of a new anhydrous polymorph, DD2 is obtained. Further heating of this mixture, or of pure DD1, up to 230 °C (only a few degrees before melting!), generates an elusive anhydrous DD3 polymorph. Their crystal structures, determined uniquely from laboratory powder diffraction data, show the isomorphous character of the DDW and DD1 forms, while the DD2 and DD3 polymorphs crystallize with markedly different unit cells. Crystals of the DD1, DD2 and DDW forms are orthorhombic, P212121, a = 29.386(1) Å; b = 10.4310(9) Å, c = 8.1422(7) Å, V = 2495.8(3) Å3 for DD1; a = 15.2639(10) Å; b = 11.7506(7) Å, c = 13.8931(11) Å, V = 2491.9(3) Å3 for DD2; a = 30.311(2) Å; b = 10.6150(9) Å, c = 7.9337(7) Å, V = 2552.7(4) Å3 for DDW; while the lattice parameters for the monoclinic P21 DD3 species are a = 11.5276(10) Å; b = 13.8135(11) Å, c = 7.8973(7) Å, β = 103.053(6)°, V = 1225.0(2) Å3. These compounds have also been fully characterized by thermo analytical methods, as well by 13C, 19F, and 1H NMR spectroscopy.

Lingua originaleInglese
pagine (da-a)102-111
Numero di pagine10
RivistaSteroids
Volume74
Numero di pubblicazione1
DOI
Stato di pubblicazionePubblicato - gen 2009

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