A Mechanistic Approach To Model the Compression Cycle of Different Toolings Based on Compression Roller Interactions

Material-Sparing Approach to Predict Tablet Capping Under Processing Compression Conditions Based on Mechanical and Molecular Properties Derived from Compaction Simulation and Crystal Structural Analysis

Present study evaluates the usability of compaction simulation-based mechanical models as a material-sparing approach to predict tablet capping under processing compression conditions using Acetaminophen (APAP) and Ibuprofen (IBU). Measured mechanical properties were evaluated using principal component analysis (PCA) and principal component regression (PCR) models. PCR models were then utilized to predict the capping score (CS) from compression pressure (CP). APAP formulations displayed a quadratic correlation between CS and CP, with CS rank order following CP of 200MPa < 300MPa < 100MPa, indicating threshold compression pressure (TCP) limit between 200 and 300 MPa, resulting in higher CS at 300 than 200 MPa regardless of increased CP. IBU formulations displayed a linear correlation between CS and CP, with CS rank order following CP of 100MPa < 200MPa < 300MPa, indicating TCP limit between 100 and 200 MPa, resulting in higher CS at 200 and 300 than 100 MPa regardless of increased CP. Molecular models were developed as validation methods to predict capping from CP. Measured XRPD patterns of compressed tablets were linked with calculated Eatt and d-spacing of slip planes and analyzed using variable component least square methods to predict TCP triggering cleavage in slip planes and leading to capping. In APAP and IBU, TCP values were predicted at 245 and 175 MPa, meaning capped tablets above these TCP limits regardless of increased CP. A similar trend was observed in CS predictions from mechanical assessment, confirming that compaction simulation-based mechanical models can predict capping risk under desired compression conditions rapidly and accurately.

Dwell time on tableting: dwell time according to force versus geometric dwell time

Dwell time is an important parameter responsible for the material deformation and the mechanical and biopharmaceutical properties of the tablet. Thus, it is widely used for scale-up purposes. The geometric dwell time (GDT) can be assumed based on the shape of the punch head and the diameter and speed of the turret. This research is aimed to compare compaction simulator-recorded dwell time according to force (DTF) and the GDT calculated for the simulated rotary tablet press using the microcrystalline cellulose and calcium phosphate mixtures (CEOLUS™ UF-711 and DI-CAFOS® A60) in different proportions. Tablets were prepared, and DTF was analyzed with a compaction simulator (STYL'One Nano and Alix software) upon simulating a small rotary press at 70 rpm and a compression pressure of 10-50 kN (100-500 MPa). While GDT comprised of 14.4 ms, DTF was compression force and formulation dependent. The differences between the DTF values of the formulations decreased as the compression force increased, which was most pronounced at compression forces of 10 and 15 kN.

Impact of die wall material on the mechanical properties of paracetamol tablets

Tablet quality can be affected by material, configuration and design of the tooling which comprise punches and dies. Much research attention had centred around punches, with very little reported on the dies. Dies with modified bore lining materials or inserts are available for special applications. However, the influence of such die types on tablet properties and the compaction process has not been well studied. Often, the reason for selecting dies with harder lining material is for improved wear resistance. In this study, flat-faced and convex-faced tablets were produced from paracetamol granules using dies with different bore inserts. Tablet properties and response parameters of the compaction process were evaluated to understand the impact of die mechanical and surface properties on the compacts formed. Compaction pressure was found to have the greatest impact on tablet elastic recovery (r ≥ 0.96, p < 0.01 in all bivariate correlations) and thus affecting the tensile strength. Choice of die inserts could impact the mechanical properties of convex-faced paracetamol tablets, particularly at high compaction pressures.

Tablet capping predictions of model materials using multivariate approach

The present study demonstrated the prediction of predominant root causes of capping behavior as a function of the powder rheological and the mechanical behavior of Acetaminophen (APAP) and Ibuprofen (IBU). The authors analyzed powder rheological properties for powder blend permeability, pressure drop, and cohesion. The measured deformation properties were compact porosity, internal air pressure, Brinell hardness, and tensile strength. The data were evaluated qualitatively and quantitatively using multivariate techniques, such as principal component analysis (PCA) and principal component regression (PCR) models, respectively, to identify the effect of powder air entrapment efficiency and mechanical behavior on the tablet capping score. The PCA model indicated that pressure drop, cohesion, API amount, and compression pressure correlated positively, whereas permeability, porosity, internal air pressure, Brinell hardness, and tensile strength correlated negatively to the capping potential. APAP and IBU also showed two independent mechanisms as a function of their amount on the capping score at all compression pressures. APAP and IBU followed an exponential and linear relationship, respectively. Furthermore, the dominant powder rheological and deformation behavior affecting the capping score of each material was identified and quantified using two separate PCR models. These models showed that APAP capping was predominantly dependent on its powder properties, while that of IBU was predominantly based on its deformation properties. In conclusion, APAP and IBU compacts capping had respective air induced and deformation induced capping behavior. The proposed approach can aid in understanding the underlying mechanisms of capping and developing an effective, optimized strategy to ensure tablet quality.