will crystallize upstream of the impinging jets and 2 sufficient supersaturation will be developed in the impinging jets to cause nucleation micromixing creates temperature and compositional uniformity throughout the mixture prior to the start of nucleation to obtain the smallest particle size of aripiprazole the highest possible concentration of aripiprazole in the organic solvent should be employed thus the starting solution of aripiprazole in organic solvent preferably ethanol will contain from about 0 01 to about 0 1 kg l aripiprazole preferably from about 0 04 to about 0 06 kg l aripiprazole in a most preferred embodiment the aripiprazole will be present in an amount of about 0 05 kg l the organic solvent will preferably be ethanol most preferably from about 92 to about 97 ethanol with the remainder being water other organic solvents such as methanol ethyl acetate acetone acetonitrile acetic acid or isopropyl alcohol or mixtures of two or more thereof or mixtures with water may be employed the two streams namely the stream of the solution of aripiprazole in the organic solvent and the stream of anti solvent are characterized as jet streams in that they will be made to strike each other head on at high linear velocities with a minimum of 5 m s the flow rates will be determined by the diameter of the jet nozzles employed to deliver the streams and the rate at which the streams are pumped through the nozzles.