An experimental study of a spring-loaded needle-free injector: Influence of the ejection volume and injector orifice diameter.

Needle-free injection is an alternative strategy to conventional needle injection in the field of drug delivery. This approach offers a number of advantages, especially in reducing complaints of needle phobia and avoiding the occurrence of accidental needle stick injuries. The ejection volume and orifice diameter are inherently important in determining the injection depth and percent delivery. In this study, we investigate the dispersion pattern of liquid penetration into gels and porcine tissues using a needle-free injector with ejection volumes of 0.05 to 0.35 mL and orifice diameters of 0.17 to 0.50 mm. In addition, the influence of the two parameters is analyzed quantitatively on the dispersion pattern through impact experiments and injection experiments. Furthermore, an equation of the jet power calculated by the ejection volume and orifice diameter is proposed to describe the delivery fraction of the injection experiments. Controls of the ejection volume and orifice diameter are demonstrated to help achieve a more effective injection process and a better injection experience. [ABSTRACT FROM AUTHOR]