In-line porosity and hardness monitoring of tablets by means of optical coherence tomography

In-line monitoring of critical quality attributes (CQAs) during a tableting process is an essential step toward a real-time release strategy. Such CQAs can be the tablet mass, the API content, dissolution, hardness and tensile strength. Since dissolution testing is laborious and time-consuming and cannot be performed in-line, it is desirable to replace dissolution testing with predictive models based on other CQAs that affect the dissolution characteristics, such as the tablet porosity and hardness. Traditionally, porosity is determined offline via gas adsorption methods or other techniques, such as Terahertz spectroscopy or gas in scattering media absorption spectroscopy.

Highlights

Optical coherence tomography for the estimation of.

Tablet porosity.

Tablet hardness.

Real-time in-line OCT measurements and porosity prediction directly after the tablet press.

Tablet hardness is typically established using a hardness tester. While these destructive tests can readily be performed at-line, they have limited applicability in in-line settings for a high-percentage inspection. Optical coherence tomography (OCT) has recently been proposed as a possible tool for determining quality attributes. This work describes the first application of OCT for the prediction of tablet porosity and hardness. OCT measurements of tablets produced in a ConsiGma 25™ tableting line and a Stylcam 200R compaction simulator in several compaction force settings were performed and correlated with the porosity and hardness.

It was demonstrated that OCT can easily be installed in-line and provide real-time information about critical material attributes. These insights confirm the applicability of OCT as a real-time quality control tool and its potential to replace time-consuming and destructive offline measurements.

Materials

Two types of tablets were used in this study. The first type of tablets was produced at five different compaction forces in the continuous tableting line. Additional tablets were manufactured at six different compaction forces in the compaction simulator. During the tableting process, the OCT system OSeeT Pharma 1D (Phyllon GmbH, Austria) was installed above a conveyor belt directly after the tablet press.

Elisabeth Fink, Selma Celikovic, Rúben Martins Fraga, Johan Remmelgas, Jakob Rehrl, Johannes Khinast,
In-line porosity and hardness monitoring of tablets by means of optical coherence tomography, International Journal of Pharmaceutics, Volume 666, 2024, 124808, ISSN 0378-5173, https://doi.org/10.1016/j.ijpharm.2024.124808.