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Shock Waves

, Volume 10, Issue 6, pp 395–404 | Cite as

Investigations of gas and particle dynamics in first generation needle-free drug delivery devices

  • N.J. Quinlan
  • M.A.F. Kendall
  • B.J. Bellhouse
  • R.W. Ainsworth
Original Article

Abstract. Transdermal powdered drug delivery involves the propulsion of solid drug particles into the skin by means of high-speed gas-particle flow. The fluid dynamics of this technology have been investigated in devices consisting of a convergent-divergent nozzle located downstream of a bursting membrane, which serves both to initiate gas flow (functioning as the diaphragm of a shock tube) and to retain the drug particles before actuation. Pressure surveys of flow in devices with contoured nozzles of relatively low exit-to-throat area ratio and a conical nozzle of higher area ratio have indicated a starting process of approximately 200 \({\mu}\)s typical duration, followed by a quasi-steady supersonic flow. The velocity of drug particles exiting the contoured nozzles was measured at up to 1050 m/s, indicating that particle acceleration took place primarily in the quasi-steady flow. In the conical nozzle, which had larger exit area ratio, the quasi-steady nozzle flow was found to be overexpanded, resulting in a shock system within the nozzle. Particles were typically delivered by these nozzles at 400 m/s, suggesting that the starting process and the quasi-steady shock processed flow are both responsible for acceleration of the particle payload. The larger exit area of the conical nozzle tested enables drug delivery over a larger target disc, which may be advantageous.

Key words: Needle-free drug delivery, Transdermal powdered drug delivery, Powder injection, Biolistics, Supersonic nozzle, Shock tube, Doppler global velocimetry 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • N.J. Quinlan
    • 1
  • M.A.F. Kendall
    • 1
  • B.J. Bellhouse
    • 1
  • R.W. Ainsworth
    • 2
  1. 1.PowderJect Centre for Gene and Drug Delivery Research, University of Oxford, Oxford OX2 6PE, UK GB
  2. 2.Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK GB

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