Simulation of particle size segregation in a pharmaceutical tablet press lab-scale gravity feeder

Evolution characteristics of micromechanics provides insights into the microstructure of pharmaceutical tablets fabricated by bimodal mixtures

This research focuses on the evolution of mechanical behavior of bimodal mixtures undergoing compaction and diametrical compression. The clusters were built and discrete element method (DEM) was used to investigate the densification process and micromechanics of bimodal mixtures. Additionally, a more comprehensive investigate of the respective breakage of the bimodal mixtures has been carried out. On this basis, qualitative and quantitative analysis of the compressive force, force chain, contact bonds and density field evolution characteristics of the clusters are investigated during the compression process. The entire loading process of the clusters is divided into three stages: rearrangement, breakage and elastic-plastic deformation. Additionally, there are differences in the evolution of micromechanics behavior of different particles in the bimodal mixture, with pregelatinized starch breakage and deformation occurring before microcrystalline cellulose. With the tablet deformation, the fragmentation process of the tablet started at the point of contact and extended toward the center, and the curvature of the force chain increased. This approach may potentially hold a valuable new information relevant to important transformation forms batch manufacturing to advanced manufacturing for the oral solid dosage form.

Lactose in tablets: Functionality, critical material attributes, applications, modifications and co-processed excipients

Lactose is one of the most widespread excipients used in the pharmaceutical industry. Because of its water solubility and acceptable flowability, lactose is generally added into tablet formulation to improve wettability and undesirable flowability. Based on Quality by Design, a better understanding of the critical material attributes (CMAs) of raw materials is beneficial in guiding the improvement of tablet quality and the development of lactose. Additionally, the modifications and co-processing of lactose can introduce more-desirable characteristics to the resulting particles. This review focuses on the functionality, CMAs, applications, modifications and co-processing of lactose in tablets.

Numerical analysis of die filling with a forced feeder using GPU-enhanced discrete element methods

Understanding die filling behaviour of powders is critical in developing optimal formulation and processes in various industries, such as pharmaceuticals and fine chemicals. In this paper, forced die filling is analysed using a graphics processing unit (GPU) based discrete element method (DEM), for which a powder feeder equipped with a wired stirrer is considered. The influences of operating parameters, such as the initial powder bed height, the filling speed, and the stirrer speed, on the die filling performance are systematically explored. It is shown that a larger initial powder bed height leads to a higher filling ratio, which can be attributed to a higher filling intensity; while the deposited particle mass in the die is almost independent of the powder bed height, when the initial fill level is larger than a critical bed height. Additionally, the filling ratio slightly increases with the increase of stirrer speed for cases with a stirrer, while the filling ratios are lower than that without a stirrer, which is attributed to the stirrer occupying some space above the die and reducing the effective discharge area. The obtained results can provide useful information for optimising the feeder system design and the operating condition.

Blend Segregation in Tablets Manufacturing and Its Effect on Drug Content Uniformity-A Review

Content uniformity (CU) of the active pharmaceutical ingredient is a critical quality attribute of tablets as a dosage form, ensuring reproducible drug potency. Failure to meet the accepted uniformity in the final product may be caused either by suboptimal mixing and insufficient initial blend homogeneity, or may result from further particle segregation during storage, transfer or the compression process itself. This review presents the most relevant powder segregation mechanisms in tablet manufacturing and summarizes the currently available, up-to-date research on segregation and uniformity loss at the various stages of production process—the blend transfer from the bulk container to the tablet press, filling and discharge from the feeding hopper, as well as die filling. Formulation and processing factors affecting the occurrence of segregation and tablets’ CU are reviewed and recommendations for minimizing the risk of content uniformity failure in tablets are considered herein, including the perspective of continuous manufacturing.

Experimental investigation and modelling of tensile strength of pharmaceutical tablets based on shear force applied by feed frame paddles

The feed frame is an essential device used in a rotary tablet press and it improves the performance of the powder filling process into dies. However, the feed frame affects critical quality attributes such as a tensile strength and a dissolution negatively due to a shear applied to powders from feed frame paddles, leading to over-lubrication. This effects may be significant for shear sensitive materials. The work focuses on the effect of tablet press parameters (die disk speed and feed frame speed) and mixture composition (amount of magnesium stearate) on the tensile strength and the prediction of the tensile strength by considering the extent of shear. It is found that within the investigated range of tablet press parameters and the amount of magnesium stearate, the feed frame speed and the amount of magnesium stearate have an impact on the tensile strength. Furthermore, a lubrication model based on the extent of shear is presented to predict the decreasing trend of the tensile strength of tablets during tableting process and the results demonstrate that the prediction of tensile strength is in good agreement with experimental measurements.

Powder flow during linear and rotary die filling

In the pharmaceutical industry, linear die filling is widely employed in R&D, while rotary die filling is very common in commercial production. It is not clear if powder die filling behaviour in a linear die filling system is representative of the flow performance in a rotary tablet press. In this study, a linear die filling system and a rotary die filling system were used to examine flow behaviours of both poor-flowing and free-flowing powders. It was found that the performance of poor-flowing powder in the linear die filling system is slightly better than that in the rotary die filling system, while the performance of free-flowing powders in the linear die filling system is similar to that in the rotary die filling system. Hence, it is suitable to use the linear die filling system to estimate the flow behaviour during rotary die filling with free-flowing powders, but caution needs to be taken when poor-flowing powders are used.