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Needle-free jet injections are actuated by a pressure impulse that can be delivered by different mechanisms to generate high-speed jets (Vj ∼ 102 m/s). During filling and transportation of disposable cartridges and ampoules, bubbles can form, which can be problematic especially for viscous fluids. Here, we report on the effect of location and size of entrapped air pockets in cartridges used in spring-powered jet injections. As air bubbles pass through the orifice, they undergo depressurization, which results in intermittent atomization and spray formation, temporarily increasing the jet dispersion. Atomization and dispersion of the jet can lead to product loss during an injection. We find that the effect of bubble location on the jet exit speed, delivery efficiency, and the projected area of the blebs formed after the injection was statistically significant (p < 0.05). The findings of this study have implications for the development of pre-filled cartridges for jet injection applications.
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Feasibility of using negative pressure for jet injection applications
We report on an experimental study of high-speed micro-scale liquid jets ejected into low-pressure environments, which has applications for the use of negative pressure modules in jet injector systems. The jets were impulsively started by the action of a stiff spring-piston and ejected through a narrow orifice, D_{0} ~ 100 μm, into partial vacuums ranging from atmospheric pressure down to -80 kPa. We find that due to the high exit velocity, V_{j} ~ 100 m/s, the main jet stream is largely unaffected, but we reveal some fascinating fine features during the startup phase, largely due to the presence of a small liquid volume pulled through the orifice prior to actuating the jet. In particular, as the pressure decreases, the start-up time increases and the initial spray becomes more pronounced. However, the primary outcome of this feasibility study is that use of negative pressures is viable for jet injector applications, and we hypothesize an optimal range of working pressures and configurations.
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- Award ID(s):
- 1749382
- PAR ID:
- 10312995
- Date Published:
- Journal Name:
- Journal of drug delivery science and technology
- Volume:
- 63
- ISSN:
- 1773-2247
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.jddst.2021.102395
