(719d) 2D-Inkjet Printing for Pharmaceutical Particle Engineering

Modern, highly potent API’s often show poor solubility and handling characteristics. Spray drying has been used as a Particle Engineering platform enabling the simultaneous improvement of the biovailability and processability of API’s. As spray drying has several drawbacks, such as inconsistent quality (owing to the challenges in the control of the droplets’ size), difficult scale up and the necessity of a large feedstock, the development of alternatives is of high potential for the (bio) pharmaceutical sector. The possibility of using 2D-inkjet printing as a replacement to such spray drying processes was investigated. By dispensing a controlled amount of liquid on a substrate, consistent quality can be achieved. The production can be easily scaled out by numbering up the nozzles. Also only a very limited amount, of a few grams of material, is needed for initial feasibility studies.

In order to reproducibly produce droplets and particles, a stable formulation needs to be found. Also the re-crystallization and drying kinetics are of high importance, as they influence the properties of the final particle severely. Formulations consisting of surrogate substances, API’s, polymers and other excipients were tested and analyzed regarding their stability. The surface/droplet interactions were optimized by altering the substrate material and surface roughness, in combination with the volume of the deposited droplet. Dimensionless numbers provided the guidance for this activity. Finally, the drying and solidification were manipulated by altering the process temperature.

By identifying the critical parameters for 2D-inkjet printing process it was possible to achieve spherical particles, starting from very poor solidification behavior (i.e. coffee ring formation, flat structures). These particles were further characterized regarding their polymorphic forms (DSC, SWAXS) and shape (SEM), to find the optimal process for the used substances.

Summarizing, this presentation will show how to use 2D-inkjet printing for particle engineering purposes, leading to reliable and reproducible results for pharmaceutical applications.