Details for Patent: 9,629,960

Title:	Needleless injector
Abstract:	A needleless injector has a syringe body having an opening at one end, a piston housed within the syringe body for urging a liquid within the syringe body through the opening and a ram for driving the piston. A shock absorbing component is provided for reducing an initial transfer of force from the ram to the piston. The initial rate of pressure increase on the liquid is reduced, thereby controlling the rate of collapse of gas bubbles in the liquid.
Inventor(s):	Green; Terry (Norfolk, GB)
Assignee:	ZOGENIX, INC. (Emeryville, CA)
Filing Date:	Aug 29, 2014
Application Number:	14/473,580
Claims:	1. A needle-free injector for injecting through skin, comprising: a piston housed within a syringe body; a power source for applying an initial force to a ram to initiate delivery of a liquid and collapse of a bubble in the liquid; wherein during a first stage of delivery, a reduced force is applied by the ram to a piston which applies force to the liquid in the first stage of delivery thereby causing the bubble to collapse in a slow, controlled manner; and further wherein during a second stage of the delivery, the ram and piston are configured in the needle-free injector so as to transfer energy of the ram to the piston wherein the piston applies force to the liquid in the second stage; wherein pressure in the liquid during the second stage is sufficiently high to enable an initial pulse of liquid to penetrate skin. 2. A needle free injector for injecting through skin, comprising a piston housed within a syringe body while collapsing a bubble in the liquid; a ram for driving the piston thereby causing liquid to be driven out of an exit opening of the syringe body; a component between the ram and the piston; wherein the ram, piston, and component are configured such that; during a first stage of delivery, the component causes a reduced force to be applied to the piston which applies force to the liquid during the first stage of delivery wherein pressure applied to the liquid collapses bubble size to 1/20 or less of bubble size prior to pressure being applied; and during a second stage of the delivery, remaining energy of the ram is transferred to the piston, wherein the piston applies force to the liquid in the second stage wherein pressure in the liquid during the second stage is sufficiently high to enable an initial pulse of liquid to penetrate skin. 3. The injector of claim 2, wherein the pressure in the syringe body increases to a pressure of about 1 to about 5 Mpa upon applying a force to the ram. 4. The injector of claim 3, wherein pressure increase occurs within 200 .mu.s. 5. The injector of claim 2, wherein the component is open at both ends. 6. The injector of claim 5, wherein the component has a constant internal diameter. 7. The injector of claim 5, wherein the component has a length of between 1 mm and 5 mm. 8. A needle-free injector, comprising: a piston housed within a syringe body; a power source for applying an initial force to a ram to initiate delivery of a liquid and collapse of a bubble in the liquid; wherein during a first stage of delivery, a reduced force is applied by the ram to a piston which applies force to the liquid in the first stage of delivery thereby causing the bubble to collapse in a slow, controlled manner wherein pressure applied to the liquid collapses bubble size to 1/20 or less of its size prior to pressure being applied; and further wherein during a second stage of the delivery, the ram and piston are configured in the needle-free injector so as to transfer energy of the ram to the piston wherein the piston applies force to the liquid in the second stage.