Control of the physical form of salmeterol xinofoate

Two approaches to the generation of particles of the phenethanolamine, salm eterol xinafoate, are discussed. To produce particles with good flow proper ties a fast cooling crystallisation process was developed which delivered s almeterol xinafoate as spherical agglomerates of microcrystals which had go od powder flow characteristics and could be micronised efficiently in a flu id energy mill. In a radically different approach, salmeterol xinafoate was crystallised using supercritical carbon dioxide in the SEDS (solution enha nced dispersion by supercritical fluids) process. By means of this techniqu e the solid state form, crystal habit, and particle size of salmeterol xina foate could be effectively controlled.