Abstract: A process for the preparation of a dispersion of crystalline nano-particles in an aqueous medium comprising combining (i) a first solution comprising a substantially water-insoluble substance in a water-miscible organic solvent with; (ii) an aqueous phase comprising water and optionally a stabiliser, to form a dispersion of amorphous particles; and (iii) sonicating the dispersion of amorphous particles for a sufficient period to form crystalline nano-particles of the substantially water-insoluble substance. The process provides nano-crystals with a mean hydrodynamic diameter of less than 1 micron, particularly less than 300 nm and is particularly useful for the preparation of nano-crystalline dispersions of pharmaceutical substances.

Abstract: A process for the preparation of a stable dispersion of solid particles, in an aqueous medium comprising combining (a) a first solution comprising a substantially water-insoluble substance, a water-miscible organic solvent and an inhibitor with (b) an aqueous phase comprising water and optionally a stabiliser, thereby precipitating solid particles comprising the inhibitor and the substantially water-insoluble substance; and optionally removing the water-miscible organic solvent; wherein the inhibitor is a non-polymeric hydrophobic organic compound as defined in the description. The process provides a dispersion of solid particles in an aqueous medium, which particles exhibit reduced or substantially no particle growth mediated by Ostwald ripening.