Atomized Rapid Injection for Solvent Extraction technique (ARISE) is investigated to micronize levothyroxine sodium particles owing to get new morphology, particle size and size distribution. Experiments were carried out at 25, 40 and 50 oC, 90 and 120 bar, for drug concentrations from 2 to 7 mg/ml in ethanol. Preliminary results show either spherical or rod-like micro and nanoparticles in the 360-1,300 nm range. Further investigation is in progress to take advantage of these characteristics and propose a new drug delivery system for levothyroxine sodium.