Jennifer Setio, M.Sc.

Contents

Abstract

An important research question in the field of pharmaceutical formulations lies in addressing the poor aqueous solubility of many drug substances. A possible solution lies in the decreasing of drug particle sizes through production methods such as spray drying. However, the efficient collection of such particles post-atomisation poses a challenge. Previous investigations centered around investigating the feasibility of implementing a melt electrostatic precipitator (MESP) to separate such particles from the gas stream and directly embed them into a crystalline carrier material (Dobrowolski et al. 2019; Justen et al. 2023; Justen et al. 2024). Building on this work, the present study aims to conduct a detailed investigation of this technology through the design, construction, and development of a melt electrostatic precipitator that can be integrated into commercial spray-drying systems.

In previous investigations, an initial melt electrostatic precipitator concept has been developed, which showed the potential of this technology for the production of solid crystal suspensions (Justen et al. 2024). However, certain challenges arose, most notably the low precipitation rate of the drug particles in the precipitator, which results in an insufficient drug load in the suspension (Justen et al. 2024).

This limitation was attributed to inherent design drawbacks of the initial demonstrator. In particular, thermophoretic effects caused by temperature gradients within the precipitator were found to significantly reduce precipitation efficiency (Justen et al. 2024). Another challenge to be addressed in this work is the absence of a continuous melt exchange system within the precipitator. Such a system is essential to ensure that particle-laden melt is continuously replaced with fresh melt, thereby overcoming the discontinuous processing limitations of the previous demonstrator.

As such, one of the primary objectives of this project is to develop a certified, market-ready demonstrator of a melt electrostatic precipitator that is compatible with commercial spray-drying systems. In parallel, the project aims to further define and expand the potential application areas of this technology through comprehensive characterization of the developed demonstrator, as well as by investigating the possibility of broadening the range of materials that can be processed using this approach.

Acknowledgement

This project is made possible by the funding of the BMBF VIP+.

References

Dobrowolski, Adrian; Pieloth, Damian; Wiggers, Helmut; Thommes, Markus (2019): Electrostatic Precipitation of Submicron Particles in a Molten Carrier. In Pharmaceutics 11 (6).

Justen, Anna; Kurth, Christopher; Schaldach, Gerhard; Thommes, Markus (2023): Preparation of Micron and Submicron Particles via Spray Drying and Electrostatic Precipitation. In Chem Eng & Technol 46 (2), pp. 343–349. DOI: 10.1002/ceat.202200357.

Justen, Anna; Weltersbach, Alina Faye; Schaldach, Gerhard; Thommes, Markus (2024): Design and Characterization of a Melt Electrostatic Precipitator for Advanced Drug Formulations. In Processes  12 (1), p. 100. DOI: 10.3390/pr12010100.