The effect of ultrasound on the crystal size of aspirin produced in the supersaturated solution

The purposes of this study are controlling the crystal size of aspirin by the use of ultrasound apparatus and investigating the ultrasonic effects on crystallization phenomenon. The number of crystals was calculated or counted and the average crystal size was measured for aspirin crystals obtained under the two different supersaturation conditions. Experimental results show that ultrasound not only activates nucleation but also inhibits primary nucleation. Ultrasonic inhibition effect on primary nucleation has never been reported and the additional research is needed to understand this ultrasonic phenomenon.