  Electrohydrodynamic (EHD) generation, a commonly used method in BioMEMS,
plays a significant role in the pulsatile drug delivery system for a decade. In
this paper, an EHD based drug delivery system is well designed, which can be
used to generate a single drug droplet as small as 2.83 nL in 8.5 ms with a
total device of 2\times2\times3 mm^3, and an external supplied voltage of 1500
V. Theoretically, we derive the expressions for the size and the formation time
of a droplet generated by EHD method, while taking into account the drug supply
rate, properties of liquid, gap between two electrodes, nozzle size, and
charged droplet neutralization. This work proves a repeatable, stable and
controllable droplet generation and delivery system based on EHD method
experimentally as well as theoretically.
