Investigating key properties of model excipients and binary powder blends using ultrasonic in-die measurements on a compaction simulator

Machine learning modeling for ultrasonic quality attribute assessment of pharmaceutical tablets for continuous manufacturing and real-time release testing

In in-process quality monitoring for Continuous Manufacturing (CM) and Critical Quality Attributes (CQA) assessment for Real-time Release (RTR) testing, ultrasonic characterization is a critical technology for its direct, non-invasive, rapid, and cost-effective nature. In quality evaluation with ultrasound, relating a pharmaceutical tablet's ultrasonic response to its defect state and quality parameters is essential. However, ultrasonic CQA characterization requires a robust mathematical model, which cannot be obtained with traditional first principles-based modeling approaches. Machine Learning (ML) using experimental data is emerging as a critical analytical tool for overcoming such modeling challenges. In this work, a novel Deep Neural Network-based ML-driven Non-Destructive Evaluation (ML-NDE) modeling framework is developed, and its effectiveness for extracting and predicting three CQAs, namely defect states, compression force levels, and amounts of disintegrant, is demonstrated. Using a robotic tablet handling experimental rig, each attribute's distinct waveform dataset was acquired and utilized for training, validating, and testing the respective ML models. This study details an advanced algorithmic quality assessment framework for pharmaceutical CM in which automated RTR testing is expected to be critical in developing cost-effective in-process real-time monitoring systems. The presented ML-NDE approach has demonstrated its effectiveness through evaluations with separate (unused) test datasets.

Effect of shape on the physical properties of pharmaceutical tablets

Despite a well-established process understanding, quality issues for compressed oral solid dosage forms are frequently encountered during various drug product development and production stages. In the current work, a non-destructive contact ultrasonic experimental rig integrated with a collaborative robot arm and an advanced vision system is presented and employed to quantify the effect of the shape of a compressed tablet on its mechanical properties. It is observed that these properties are affected by the tablet geometric shapes and found to be linearly sensitive to the compaction pressures. It is demonstrated that the presented approach significantly improves the repeatability of the experimental waveform acquisition. In addition, with the increased confidence levels in waveform acquisition accuracy and corresponding pressure and shear wave speeds due to improved measurement repeatability, we conclude that pharmaceutical compact materials can indeed have a negative Poisson's ratio, therefore can be auxetic. The presented technique and instrument could find critical applications in continuous tablet manufacturing, and its real-time quality monitoring as measurement repeatability has been significantly improved, minimizing product quality variations.

Ultrasonic characterization of complete anisotropic elasticity coefficients of compressed oral solid dosage forms

In compacted materials, elastic anisotropy coupled with residual stresses could play a determining role in the manifestation of various types of defects such as capping and lamination, as it creates shear planes/bands and temporal relaxation. This internal micro-structure leads to time-delayed flaw initiation/formation, crack tip propagation under residual stresses, and ultimately product quality failures. Thus, their accurate characterization and variations are useful for understanding underlying failure mechanisms and to monitor variations in materials, processes and product quality during production prior to onset of failure. The extraction of tablet anisotropic elasticity properties is a challenging task, especially for commercial tablets with complex shapes, as shape often prevents the use of traditional destructive techniques (e.g., diametric compression testers) to produce accurate measurements. This study introduces and applies an ultrasonic approach to extracting the complete transverse isotropic elastic properties of compressed oral solid dosage forms to a commercial tablet product. A complete set of waveforms and the constitutive matrix for the compacted materials are reported. In addition, a perturbation analysis is carried out to analytically relate propagation speeds in various directions to the elastic coefficients. The proposed characterization approach is non-destructive, rapid, easy, and reliable in evaluating tablet anisotropy.