Abstract: A needle-free injection system powered by a voice-coil linear actuator is presented in order to overcome drawbacks of the common spring or compressed gas powered injection system. The mechanics of injection process is investigated. A theoretical model is established to evaluate the injection pressure under system conditions (nozzle diameter, ampoule dimension, voice-coil discharging voltage, etc.). An experimental system is set up to measure the injection pressure dynamically. The experimental results agree well with the predicted values given by the theoretical model. In-vitro injections using the current needle-free system are carried out with needle injection as control. Results show that the current magnetic force injection technology can generate enough injection pressure to pierce into skin, and the administration is absorbed in vivo faster than that through needle. The current system features simple structure, two-way operation, and controllable driving force, thus overcoming the disadvantages of traditional needle-free injection systems, and laying the foundation for the product development of novel needle-free injection system.

Key words: Injection pressure, Needle-free injection, Voice-coil actuator