(129a) Investigation of Different Continuous Drying Routes for Pharmaceuticals
World Congress on Particle Technology
Thursday, April 26, 2018 - 8:15am to 8:38am
One of those challenging process steps between primary and secondary manufacturing is the continuous drying of APIâs. During API synthesis and subsequent crystallization the desired particle properties, such as size and morphology, are tailored. However, during washing and drying these properties can be changed, due to attrition and agglomeration. Therefore, the challenge during drying is to minimize such effects.
This presentation will highlight results of drying experiments with two different drying technologies. APIs and excipients with a particle size below 100 Âµm were dried either based on extrusion or contact-convective drying technology. Variation in process settings was tested and successful configurations were found. Feed materials with different initial moisture content were processed to evaluate the drying capacity of the two dryer options. Measurements of particle size distribution, residual moisture content and flowability were conducted. Residual moisture of the dried products reached levels below 0.1%. No change in particle size distribution for the tested APIs was observed and therefore no agglomeration or attrition occurred during the drying procedure. In addition, powder flowability showed similar results prior and after drying.
The key to successful continuous drying of powders and matching specified product quality is a robust process design with consistent processability. This includes avoiding of dead zones, resulting in a narrow residence time distribution (RTD), amongst others. A narrow RTD leads to less mixing of particles with different moisture levels and results in a reduced tendency of agglomeration or attrition.