Moisture Behavior of Pharmaceutical Powder during the Tableting Process

Abstract

The moisture content of pharmaceutical powder is a key parameter contributing to tablet sticking during the tableting process. This study investigates powder moisture behavior during the compaction phase of the tableting process. Finite element analysis software COMSOL Multiphysics® 5.6 was used to simulate the compaction microcrystalline cellulose (VIVAPUR PH101) powder and predict temperature and moisture content distributions, as well as their evolution over time, during a single compaction. To validate the simulation, a near-infrared sensor and a thermal infrared camera were used to measure tablet surface temperature and surface moisture, respectively, just after ejection. The partial least squares regression (PLS) method was used to predict the surface moisture content of the ejected tablet. Thermal infrared camera images of the ejected tablet showed powder bed temperature increasing during compaction and a gradual rise in tablet temperature along with tableting runs. Simulation results showed that moisture evaporate from the compacted powder bed to the surrounding environment. The predicted surface moisture content of ejected tablets after compaction was higher compared to that of loose powder and decreased gradually as tableting runs increased. These observations suggest that the moisture evaporating from the powder bed accumulates at the interface between the punch and tablet surface. Evaporated water molecules can be physiosorbed on the punch surface and cause a capillary condensation locally at the punch and tablet interface during dwell time. Locally formed capillary bridge may induce a capillary force between tablet surface particles and the punch surface and cause the sticking.

Comprehensive Analysis of Novel Synergistic Antioxidant Formulations: Insights into Pharmacotechnical, Physical, Chemical, and Antioxidant Properties

“…On the other hand, Khan et al [ 69 ] considered that humidity over 3% breaks the particle bonds in a compact arrangement, as in capsule filling. Also, Koumbogle et al [ 70 ] revealed that moisture evaporates from a compacted powder bed to the surrounding environment, proving the importance of maintaining a low humidity content of the materials for solid-dosage products. The final formulations of the filling powders for capsules displayed an adequate water content in comparison to the initial active ingredients’ mixtures conforming to the proper selection of the excipients.…”

Encapsulation of W/O/W Acerola Emulsion by Spray Drying: Optimization, Release Kinetics, and Storage Stability

“…At elevated ERH levels, the powder adsorbs more moisture from the surrounding environment, leading to the condensation of moisture on the surface of powder particles. This condensation forms liquid bridges between particles, causing them to adhere together [48]. In addition, the moisture content of encapsulated powder spray dried at optimal inlet and outlet temperatures is approximately 3.21%, which is lower than the Mo value.…”