Determination of Mixing Efficiency in Various Laboratory-Scale Semi-Solid Formulation Techniques Through Computational Fluid Dynamics and Finite Volume Simulations

Objective

This study evaluated various mixing, homogenization, and dosing techniques for laboratory-scale semi-solid formulations, focusing on parameters such as volume, rpm, container morphology, and paddle design to determine efficiency and efficacy.

Methods

Three three-dimensional vessels were analyzed: mortar and pestle, blender, and a custom-designed conical reactor. Simulations using computational fluid dynamics (CFD) and the finite volume method were conducted to study particle trajectories and the homogenization process during the mixing, agitation, and emptying phases. Additionally, experimental validation was performed in parallel with the simulations, using similar operational conditions for each system.

Results

The CFD simulations revealed that the conical reactor was the most efficient under all conditions (high and low volumes and revolutions). Further evaluations showed that the helical (screw) paddle inside the reactor provided the highest efficiency in mixing and significantly accelerated the complete emptying of the reactor. Experimental validation corroborated the simulation results, showing a high degree of agreement between both methods and demonstrating the reliability of CFD simulations under real operational conditions.

Conclusions

The results demonstrate the relevance of the conical reactor and its helical screw paddle for improving the efficiency of mixing and dosing in semi-solid formulations, offering valuable insights for pharmacists involved in therapy customization. The findings emphasize the need for further research to refine these systems and enhance their efficiency in pharmaceutical applications.