Viscosity Analysis of a Polymer-Based Drug Delivery System Using Open-Source CFD Methods and High-Pressure Capillary Rheometry

Abstract

Abstract In this study the viscosity behavior of the polymer-based drug delivery system (Soluplus-Fenofibrate) at high shear rates was investigated using (i) Computational Fluid Dynamics (CFD) methods and (ii) experimental data acquired with a high-pressure capillary rheometer. The barrel and capillary were rebuilt in the virtual domain by means of finite-volume methods and used for fluid dynamic simulations. Our primary focus was on validating the Carreau-Winter and Yasuda material models in the Open Field Operation and Manipulation program (OpenFOAM) and investigating their usefulness in this type of simulation. First, the models were fitted to experimental data from a well-known system – polystyrene type (145D, BASF). The results showed that the Yasuda model fit must be applied to obtain the correct material properties when simulating a non-Newtonian melt flow in a wide range of shear rates. The Carreau-Winter model was found to be valid only in the zero shear-rate viscosity region. On the basis of these findings, the Soluplus-Fenofibrate system was subsequently characterized and simulated. We observed that Fenofibrate (lipid-regulating agent) acts as a plasticizer in this polymer system and decreases system viscosity at lower shear rates compared to pure the Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) at the same temperatures. Our results show that the viscosity models can be implemented accurately even for processes with high shear rates, which also involve high temperatures.