Experiment and Simulation of Electrospray Particle-Flows for Controlled Release of Drugs.

Electro HydroDynamic Atomisation (EHDA) disperses a liquid into small, highly charged droplets. We show that this method can be used to produce particles that release a drug at a desired rate. This is done by spraying a solution of bio-degradable polymers and an enzyme, which represents the effective drug. The release rate can be varied by modification of the polymer matrix. It is further demonstrated that the enzyme fully retains its functionality in the EHDA process. Practical use of this technique for medicine production requires a scaled-up design, which must be based on an adequate model of the particle flow in the charged droplet spray plume. As a step in this direction, the most important result is a scale-up relation that allows simulations of an experimental spray with millions of particles, using only a few thousand model particles. The experimental spray is examined with a Phase Doppler Particle Analyser (PDPA) set-up, and the resulting density and velocity profiles are compared to the numerical results. There is a qualitative agreement between experiment and model. [ABSTRACT FROM AUTHOR]