Numerical and Experimental Analysis of a High Speed Needle-Free Powdered Vaccine/Drug Delivery Device

Numerical Methods in Fluids

Bellhouse

2005

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SUMMARYThe authors' recently-developed code for a needle-free powdered vaccine delivery device, the epidermal powdered inject system (EPI), is summarized in this paper. The behaviour of supersonic jet ows, which accelerate micron sized powdered vaccines to penetrate human skin or mucosal tissue, is therefore of great importance. A well-established modiÿed implicit ux vector splitting (MIFVS) solver for the Navier-Stokes equations is extended to study numerically the transient supersonic jet ows of interest. A low Reynolds number k-turbulence model, with the compressibility e ect considered, is integrated into MIFVS solver to predict the turbulent structures and interactions with inherent shock systems. The results for the NASA validation case NPARC, Venturi and contoured shock tube (CST) of the EPI system are discussed.

Section: Contoured Shock Tube Systemmentioning

confidence: 99%

“…This code is then applied to prototypes of the EPI system based on the Venturi principle (Venturi [7]) and a contoured shock tube (CST [8,9]), respectively.…”

Section: Validationmentioning

confidence: 99%

Prediction of jet flows in the supersonic nozzle and diffuser

Numerical Methods in Fluids

Bellhouse

2005

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“…Key aspects of the CST concept and the principles of operation have been described in the form of space-time (x-t) diagram experimentally and computationally (Liu et al, 2002;Kendall, 2002;Truong, 2005). Essentially, diaphragm rupture forms a primary shock wave, which propagates downstream and initiates an unsteady gas flow, as in a classical shock tube (Smith, 1966;Chisnell, 1957).…”

Section: The Contoured Shock Tubementioning

confidence: 99%

“…The silencer is not considered. There is a large body of experimental data available (Liu et al, 2002;Truong, 2005) for the validation of numerical method.…”

Section: The Contoured Shock Tubementioning

confidence: 99%

“…First, simple benchtop prototypes were designed and constructed and the gas and particle flows were interrogated experimentally, analytically (Kendall et al, 2000) and numerically (Liu et al, 2002). Including the effects of the deforming tissue surface with an impinging gas jet (Hardy and Kendall, 2005), it has been shown that the simple benchtop CST does achieve the goal of delivering micro-particles to the skin with a nominally uniform velocity and spatial distribution.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical analysis of gas and micro-particle interactions in a hand-held shock-tube device

Kendall

2006

Biomed Microdevices

A unique hand-held gene gun is employed for ballistically delivering biomolecules to key cells in the skin and mucosa in the treatment of the major diseases. One of these types of devices, called the Contoured Shock Tube (CST), delivers powdered micro-particles to the skin with a narrow and highly controllable velocity distribution and a nominally uniform spatial distribution. In this paper, we apply a numerical approach to gain new insights in to the behavior of the CST prototype device. The drag correlations proposed by Henderson (1976), Igra and Takayama (1993) and Kurian and Das (1997) were applied to predict the micro-particle transport in a numerically simulated gas flow. Simulated pressure histories agree well with the corresponding static and Pitot pressure measurements, validating the CFD approach. The calculated velocity distributions show a good agreement, with the best prediction from Igra & Takayama correlation (maximum discrepancy of 5%). Key features of the gas dynamics and gas-particle interaction are discussed. Statistic analyses show a tight free-jet particle velocity distribution is achieved (570 +/- 14.7 m/s) for polystyrene particles (39 +/- 1 microm), representative of a drug payload.

Optimization of a jet‐propelled particle injection system for the uniform transdermal delivery of drug/vaccine

Biotech & Bioengineering

Kendall

2007

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A jet-propelled particle injection system, the biolistics, has been developed and employed to accelerate micro-particles for transdermal drug delivery. We have examined a prototype biolistic device employing a converging-diverging supersonic nozzle (CDSN), and found that the micro-particles were delivered with a wide velocity range (200-800 m/s) and spatial distribution. To provide a controllable system for transdermal drug delivery, we present a contoured shock-tube (CST) concept and its embodiment device. The CST configuration utilizes a quasi-steady, quasi-one dimensional and shock-free supersonic flow to deliver the micro-particles with an almost uniform velocity (the mean velocity and the standard deviation, 699 +/- 4.7 m/s) and spatial distribution. The transient gas and particle dynamics in both prototype devices are interrogated with the validated computational fluid dynamics (CFD) approach. The predicted results for static pressure and Mach number histories, gas flow structures, particle velocity distributions and gas-particle interactions are presented and interpreted. The implications for clinical uses are discussed.