A method to crystallize substances that oil out

A new approach to crystallize oily substances is described. The tendency for liquid-liquid phase separation (LLPS) is reduced by decreasing the kinetics of self-association via the formation of an intermediate amorphous network. The path to initial crystal formation followed a sequence of first freeze-drying an emulsion of solute in the solvent system followed by suspending the dried solid in water to obtain a hydrated crystalline form. This new procedure was applied successfully to a pharmaceutical organic substance that was previously isolated only as a viscous oil. Once isolated, crystals of the drug were utilized as seeds to allow the successful transformation of an emulsion of the substance into a suspension of crystalline drug solid thus avoiding the freeze-drying step. The isolated crystalline solid retained its physical and chemical purity at room temperature for at least 3 months. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.