Crystal growth and structure of a new hormonal derived compound

The 17alpha-acetoxy-6-hydroxymethyl-3,20-dioxo-19-nor-pregna-4,6-diene (C(23)H(30)O(5)), a new hormonal derived compound presenting a potential therapeutic interest for a pharmaceutical formulation, raises a problem as it precipitates spontaneously when in contact with an aqueous solution. The solubilization of this potential pharmaceutical drug was investigated to control and/or prevent crystal formation in the presence of water. The solubility limit of this potential drug, either in Cremophor(R) EL or RH40, was determined to be 2.6% (w/w). In addition, crystal growth of this compound solubilized in Cremophor(R) and in contact with aqueous environment was undertaken to improve crystal quality and size and subsequently to determine its three dimensional structure. We used a system that allows slow single crystal growth at room temperature. The crystallization system that we set-up comprised an interface between two solutions: one containing the compound solubilized either in Cremophor(R) RH40 or EL and the other containing water and glycine. The crystal structure was established by single crystal X-ray diffraction analysis. The structure refinement study revealed the presence of one water molecule with strong intermolecular hydrogen bonding leading to an atomic arrangement corresponding to an infinite chain in the [001] direction.