Based upon the mechanism of supercritical fluid assisted atomization (SAA) technology

a promising process for producing micronic particles of controlled diameter

it was proposed that the mixing between supercritical CO2 and liquid solution in the saturator was one of the key factors likely responsible for the particle size distribution (PSD) width.The SAA introduced by hydrodynamic cavitation mixer (SAA-HCM) experimental apparatus was built to intensify mass transfer and form a homogeneous fluid mixture.Using roxithromycin as the model drug

the effects of process parameters

such as cavitation generator

mixer pressure

precipitator temperature

different solvents

mass flow ratio between CO2 and liquid solution and solute concentration in the liquid solution were investigated to evaluate their influences on the morphology and size of precipitated particles.The results indicated that hydrodynamic cavitation mixer improved effectively mass transfer

and successful micronization of the roxithromycin was achieved with a narrow PSD.Most of the particles obtained by using the SAA-HCM were well-defined spherical in morphology.By adjusting process parameters

microparticles with a diameter ranging between 1μm and 3μm suitable for inhalation delivery and ultrafine microparticles with a diameter lower than 1μm could be obtained.