Abstract

We investigated different high velocity remote drug delivery systems (HVRDDS), characterized by dart mass and mechanism of drug expulsion, to identify factors contributing to tissue injury and to evaluate the potential for HVRDDS to cause significant long-term injury. Flight velocity and kinetic energy were determined by analyzing trajectories of darts of known mass using a Doppler radar chronograph. Identification of factors contributing to tissue injury was determined by using high-speed video to record impact behavior of dye-filled darts fired into hide-covered ballistics gelatin, and by measuring the dimensions of dye tracts. For some systems, dart velocities were highly variable within replicate tests resulting in low precision at target. Instability of darts in flight (yaw) also contributed to low precision. Heavy mass darts decelerated slower than lighter darts although dart length also affected this relationship. Large bore, end-ported needles consistently pushed hair or tissue into dye tracts. Rapid injection darts (explosive charge) caused deeper dye tracts than slow injection (air pressurized) darts. Further, the repulsion of rapid injection darts following impact caused separation of hide and gelatin and partial injection into the resulting space. Findings with ballistics gelatin were comparable to results obtained using animal carcasses. Overall, injury potential with HVRDDS can be reduced through various design modifications and appropriate selection of needle and charge or power setting.