(3cs) A New Continuous Spinning Disc Spinning Bowl Contactor: Drug Nanoparticle Synthesis and Mixing Studies.

Continuous processes are currently being explored in pharmaceutical industry to achieve better control over product quality. Conventional contactors often fail to meet the need of rapid mixing of process streams, minimal back-mixing and the absence of dead zones all put together warranted by some processes. Here we present a new continuous liquid-liquid contactor named spinning disc spinning bowl contactor which accomplishes rapid mixing of two liquid streams. The drops of one stream are generated from a spinning disc which impinge on the thin moving film of the other liquid on the inner wall of a spinning bowl. Both, the disc and the bowl, are fed continuously by gravity driven system.

We demonstrate continuous synthesis of spherical nanoparticles of curcumin through liquid anti-solvent precipitation route using the new contactor. Measurement of Particle size using SEM shows particles formed are below 200 nm under all operating conditions. Further we use a standard diagnostic competing parallel reaction system (Iodide-iodate reaction system) to understand the role of flow rate, bowl speed, and disc speed on mixing. The reaction product is analysed for absorbance at 353 nm using UV-Visible spectrophotometer. Use of Engulfment model available in literature helps to correlate the experimentally obtained mixing measure (segregation index) with a mixing time, which is estimated to be 2-4 ms under best operating conditions. Exposure controlled image of transparent bowl wall moving at high speed explains some trends and points at the crucial role of film stability to ensure good micro-mixing condition.