To be efficient, inspired, and informed.
Angela and Simon recommended two papers to learn more about the crucial role microstructures play in tablet development.
Here are some key takeaways from these papers:
1. How microstructure controls disintegration and dissolution
Porosity and domain structure directly influence tablet performances, such as liquid uptake, mechanical integrity, and release behavior. Small shifts in structure can create large, sometimes unexpected changes in disintegration time and dissolution rate. Characteristics like pore connectivity and the spatial distribution of formulation components often show strong correlations with dissolution behavior, making microstructure analysis a practical way to diagnose issues when performance changes.
2. Practical ways to characterize microstructure
CT is one of the most comprehensive characterization techniques, but no single technique captures everything, so the best method depends on the structural scale of interest. Density-based porosity estimates and true-density measurements (via pycnometry or pressure–density modeling) are used routinely. Micro-CT provides 3D structural information but is relatively slow and resolution-limited for micro-pores. Mercury intrusion porosimetry and SEM-based image analysis offer pore size or domain size information but come with constraints related to fragility, toxicity, small sample size, or lack of location information. Chemical imaging (NIR, Raman) covers compositional distribution. Combined, these methods build a coherent picture without overrelying on any single measurement.
3. How R&D and QC analyze microstructure differently
R&D uses microstructure to understand mechanisms in detail and engineer robust formulations. For CT, R&D might tolerate longer scan time to gain higher resolution. QC focuses on consistency, using simpler, high-throughput measurements to focus on a few key parameters, such as porosity. The main goal is to monitor one or two characteristics and ensure that they stay within the acceptable envelope defined during development. Advanced methods, or slower but higher resolution scans might be used occasionally when diagnosing deviations rather than for routine monitoring.
