Transient modelling of impact driven needle-free injectors.

Area of Science:

• Biomedical Engineering
• Drug Delivery Systems
• Fluid Dynamics

Background:

• Needle-free jet injectors (NFJIs) offer an alternative to hypodermic needles for transdermal drug delivery.
• NFJIs operate in two phases: initial peak-pressure and constant jet speed injection.
• Key parameters like jet velocity and diameter are crucial for achieving target tissue penetration.

Purpose of the Study:

• To investigate how cartridge design and fluid properties influence jet velocity and pressure profiles in NFJIs.
• To enable rapid and accurate estimation of cartridge pressure and jet velocities for device manufacturers.
• To refine mathematical models for predicting NFJI hydrodynamics.

Main Methods:

• Transient numerical simulations were employed, using experimental plunger displacement data.
• Analysis focused on jet velocity and stagnation pressure profiles.
• Empirical correlations for pressure loss in various cartridge geometries were utilized.

Main Results:

• Fluid viscosity and cartridge-plunger friction were identified as critical factors influencing jet velocity.
• An extended mathematical approach accurately predicted jet hydrodynamics.
• Tailoring actuation power and nozzle geometry allows delivery of various viscosities to the intradermal region.

Conclusions:

• Cartridge geometry and fluid properties significantly impact NFJI performance.
• Accurate prediction of hydrodynamics is achievable through refined mathematical modeling.
• NFJI technology can be optimized for targeted drug delivery of diverse formulations.