The Study of Equalizing Injection Force in Multiple Injecting Needle-Free Injector
The use of a needle-free injector (NFI) that inject drag solution into the skin by applying pressure is increasing with an increase in the number of diabetes patients. The medical treatment of diabetes involves insulin administration several times a day. Therefore, the purpose of this study is to improve the usability of the NFI and the development of the NFI that can be used for multiple injections with a one-time administration preparation. The existing the NFI inject the drag solution by the application of elastic force. The problem with these the NFI is the maintenance of a constant injection force each time that they are used, because the elastic force decreases with an increase in the number of injection times. We found that it is possible to assist the injection force by generating an impact force at the time of injection. Therefore, the impact clearance is set in the NFI. Certain experiments have been carried out to investigate the relationship between the impact clearance and injection force. The results of these experiments reveal that the injection force is maintained at a constant value by increasing the impact clearance when the spring power decreases. A trial model of the multiple-injecting the NFI is developed on the basis of these results. It is evaluated under the condition that a constant injection force is maintained even in the case of multiple injections.
Tojiro Aoyama, Hideki Aoyama, Atsushi Matsubara, Hayato Yoshioka and Libo Zhou
M. Kudo et al., "The Study of Equalizing Injection Force in Multiple Injecting Needle-Free Injector", Key Engineering Materials, Vols. 523-524, pp. 686-691, 2012