Crystal nucleation rates from induction time measurements and microfluidic devices

Nucleation is one of the key processes in crystallization of pharmaceutical products as it determines various crystal product quality attributes such as crystal size distribution and crystal structure. Therefore, understanding the fundamentals of nucleation is key to attaining control over these properties. Nucleation refers to the generation of a new phase of nanoscopic clusters of molecules from a supersaturated mother liquor.

Microfluidic devices are a promising tool for the analysis of crystallisation kinetics due to their ability to create and control a large number of droplets of known composition in isolated, controlled conditions quickly.

Recent work within CMAC has shown that concentration is enhanced at interfaces, particularly oil/solution interfaces (McKechnie et al.). This is of particular significance for work in microfluidic devices, where crystallising droplets are in constant contact with oil and often have significantly greater surface to volume ratio. In this work nucleation rates were calculated from small scale (1 ml) induction time measurements using a technique developed by Jiang et al. These results are to be compared with those gained from micro scale nucleation measurements in a microfluidic device. This work endeavours to present microfluidics as a tool for simple, quick acquisition of nucleation rate data and analyse the effect of solution oil/interface on nucleation rate.