Performance Analysis of a Non-invasive Drug Delivery System Using CFD Approach

The development of needleless drug delivery systems (NDDS) has garnered significant attention as an alternative to traditional needle-based methods, which often lead to issues such as needle phobia, risk of needle-stick injuries, and infection. The present work emphasizes an effort in the same direction to utilize shock waves for NDDS. The system mainly consists of a shock tube and a delivery nozzle, separated by a flexible membrane. The shock wave generated in a shock tube is characterized by a sudden increase in pressure, temperature, and velocity, creating a highly energetic environment. This energy is utilized to propel the drugs at high speeds, enabling them to penetrate the skin without the use of a needle. Considerations are given for a 2-D axisymmetric numerical model of NDDS to capture the shock dynamics and observe the pressure intensity near the flexible membrane. Fluid–structure interaction (FSI) involves the transfer of energy from the shock wave to the flexible membrane. In this short interaction, the membrane undergoes an elastic deformation and accelerates the liquid drugs available in the delivery nozzle towards the target surface. The flow behaviour of the drug ejection from the nozzle is analyzed. The study employs ANSYS Fluent 2023 to observe the pre- and post-shock pressures inside the shock tube. The numerical model is validated using an analytical approach and previously published experimental results. Furthermore, COMSOL Multiphysics 6.1 is used to perform analysis on the delivery nozzle chamber to study the membrane behaviour and attain the drug ejection velocity of approx. 100 m/s. It is observed that the ejection velocity is also influenced by the shock strength (P2/P1) and reflected shock pressure (P5). Moreover, the parametric simulation of the system enhances the pressure near the flexible membrane and improves the drug ejection velocity.