抄録
In order to improve bioavailability of active pharmaceutical ingredients (APIs), the control of crystal size is important issue. In this paper, the effect of multi-frequency ultrasonic irradiation on the crystallization of potash alum was investigated. Experiments have been carried out in a batch stirred vessel with cross-arranged ultrasonic transducers. Firstly, low frequency at 25kHz is effective for enhancing nucleation rate compared with high frequency at 1MHz due to ultrasonic cavitation effect. Secondly, it has been found that combined irradiation of two frequencies of ultrasound can enhance primary nucleation and decrease the size of produced crystals compared with single frequency irradiation. The effect of multi-frequency irradiation has been discussed in relation to ultrasonic power.
