Definition of a solvent system for spherical crystallization of salbutamolsulfate by quasi-emulsion solvent diffusion (QESD) method

In this paper we describe how the spherical crystallization process by QESD method can be applied to a water-soluble drug, salbutamol sulfate. The typ e of solvent, antisolvent, and emulsifier and the concentration of emulsifi er to be used for the production of spherical particles with a size range 8 0-500 mum are determined. Furthermore, the solvent/antisolvent ratio and th e temperature difference between them (DeltaT) are studied. It was observed that, in the case of salbutamol sulfate, the DeltaT value has no influence on the formation of spherical particles. A very large metastable zone of s albutamol sulfate in water could explain this phenomenon. Finally, the infl uence of emulsifier concentration and of maturation time on the size of sph erical particles is studied. The results show that these two parameters mus t be fixed to control the size of the recovered particles. (C) 2001 Wiley-L iss, Inc. and the American Pharmaceutical Association.