Control of Dispersed Particle Formation by Use of a Vibrating Orifice Aerosol Generator

The industrial production of many solid chemicals requires the production and gathering of dispersed particles. In the case of pharmaceutical compounds, the size, morphology (shape) and internal structure (polymorph) of these particles are important. Obtaining the desired size particles usually requires a two-step process of synthesizing the compound then using filtration or separation downstream to isolate the desired portion. Particle synthesis of the correct polymorph and morphology usually requires specific chemistry (solvent, additives, etc) and/or processing. This work advances the understanding of particle production through the use of a Vibrating Orifice Aerosol Generator to create and collect dispersed particles and the resulting morphologies and polymorphs that are possible. Analysis by scanning electron microscopy (SEM), nanoindentation, and X-ray diffraction (XRD) suggest that uniform droplet evaporation can be a tool to obtain precise and unique morphologies and polymorphs using alternative solutions and solvents. Experimental results using glycine and serine indicate that the polymorph and morphology of resulting particles can be controlled by solvent and solution concentration alone. Further, a specific polymorph that could not be obtained by other crystallization techniques under similar conditions was able to be isolated using the VOAG.   Thus, this demonstrates that this could open up additional industrial use for testing for metastable polymorphs.