Acta Cryst. (2002). E58, o712-o714  [ doi:10.1107/S1600536802009406 ]

Anhydrous beclomethasone dipropionate

J. W. Millard and P. B. Myrdal

Abstract: The anhydrous crystal structure of the title compound, 9-chloro-16-methyl-3,20-dioxo-1,4-pregnadiene-11,17,21-triol 17,21-dipropionate, C₂₈H₃₇ClO₇, was determined by single-crystal X-ray diffractometry using direct methods. Beclomethasone dipropionate, BDP, is an important pharmaceutical steroid for the treatment of asthma. It is formulated for inhalation delivery either as a solution or as a suspension of crystals in liquefied halogenated-alkanes. The physico-chemical properties of the crystals in suspension are of critical importance. Density will affect suspendability and settling rate, and different crystal forms may have significantly different dissolution rates in vivo. Until now, only the monohydrate form of BDP has been published [Duax et al. (1981). Acta Cryst. B37, 383-387]. This study presents the structure of the anhydrous form of BDP. The anhydrous form is intermolecularly hydrogen bonded and its efficient packing results in a more dense crystal (1.362  Mg  m^-3) than the published monohydrate form (1.287  Mg  m^-3).

Online 8 June 2002

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