Needle-free injection liquid

As previously described, liquid needle-free injection was the first needle-free technology to be developed and has been the focus of the vast majority of companies working in the industry. Indeed, many millions of... 

Powder injection applies many of the principles of pulmonary delivery of dry powders to the lungs The drug has to be in the form of very small particles, is dispensed from a reservoir, and is delivered as an aerosol i.e., particles are dispersed in a gas. Liquid or dissolved drug can be delivered by precipitation or adsorption onto carrier particles. The big difference with pulmonary delivery is the momentum at which the particles are delivered. Driven by a high-pressure helium gas stream, the particles travel fast enough to penetrate the outer layer of the skin, the stratum corneum. The design of devices to deliver needle-free injection of solids was pioneered by researchers at the University of Oxford who founded PowderJect Pharmaceuticals PLC in 1993 (now PowderMed Ltd.) to develop the only powder-based technology so far. Since that... 

Dry-powder inhalers (DPIs) deliver the drug to the respiratory tract in aerosol form. An aerosol is by definition a suspension of free liquid or solid fine particles in a gas phase, which is air in the case of DPIs (and a compressed gas in the case of needle-free injection). The most prominent characteristic that determines the delivery of drug particles to the lungs is the particle size, although particle shape and density are also of considerable importance for the behavior of an aerosol in the respiratory tract (Brain and Blanchard 1993 Gonda 1992 Heyder et al. 1986 Agnew 1984 Heyder et al. 1980). 

The key to achieving a successful injection with a needle-free system is to understand the necessary mechanics for the consistent penetration of skin and fat with a liquid jet, without causing unnecessary trauma to the tissues and to the molecule being delivered. Only recently have detailed studies of the fluid mechanics of needle-free injection appeared. The fluid mechanics conditions necessary for a consistent targeted needle-free injection are addressed in the following section. 

King, T. Needle-free injection protein delivery via pre-filled needle-free liquid injection. Drug Delivery Technol. 2003, 3 (7), 52-57. 

Needle-Free Drug Delivery Systems. The three types of needle-free drug delivery systems are liquid, powder, and depot injections. Each of these types uses some form of mechanical compression to create enough pressure to force the medication into the skin. Although these needle-free delivery systems cost more initially and require more technical expertise... 

Figure 1 is a schematic diagram of the experimental setup. The test section is a horizontal rectangular channel 40 mm in height (H), 160 mm in width (W), and 6,000 mm in length (L). The rectangular channel is completely constructed of transparent acrylic resin, as shown in Figure 2. Tap water and air are used as the gas and liquid phases, respectively. Water is circulated by a 2.2 kW pump fed by a water reservoir 4.2 m away. Air bubbles are injected into the horizontal channel from the upper inner surface of the channel. An array of capillary needles produces bubbles 10-100 mm in length. Before the air and water are mixed, their volumetric flow rates are measured. After leaving the horizontal channel, the gas-liquid mixture is dumped into a tank that acts as a bubble remover when the liquid phase is recirculated it is free of bubbles. At the end of the horizontal channel tracer particles are added to the water to act as ultrasound reflectors. The mean particle diameter is 200 pm and the particle density is 1020 kg/m3. These tracer particles are assumed to...

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