(410e) Process Performance of a Novel Continuous Process Line for Drying of an Active Pharmaceutical Ingredient

Lately, there has been increased interest in linking primary and secondary manufacturing. Especially, the increasing pressure towards cost effectiveness and cost reduction during phases II and III of drug product development is driving this demand.

After continuous API synthesis the steps filtration, washing and drying are still done in batch processes. This is mainly due to the lack of available equipment for pharmaceutical production. Additionally, drying processes are challenging. During crystallization particles are tailored with much effort and therefore, these properties must be maintained during subsequent process steps. However, during drying attrition and agglomeration compete, leading to a change of particle size distribution (PSD) of the primary particles.

This talk will show the design of a continuous process route for drying, considering also the upstream washing step, which strongly influences the agglomeration process during drying. This process line is an option to close the gap between primary and secondary continuous manufacturing.

The process starts with a continuous washing and filtration step. In the final filtration step the suspension is concentrated to the maximum solid content, which can be transported to the dryer. A novel contact convective drying technology was developed, which allows achieving a final moisture below 1% while not impacting the PSD. The process line is designed to dry cohesive temperature sensitive materials with a mass flow of 0.5 to 2 kg/h of dry substance. With this novel drying process, it is possible to gently dry particles with a particle size below 100 µm without changing the particle size. Also, this drying process guarantees that there is no agglomeration inside the dryer, ensuring a suitable residence time distribution. For this work Ibuprofen and other substances have been used to test PSD and residence time distribution, as well as drying efficiency. To prove that particle shape and surface did not change during the drying process, scanning electron microscopy was used.

In summary, it was shown that this novel contact convective drying technology is suitable to dry temperature sensitive cohesive particles at a mass flow range suitable for pharmaceutical production.