Needle free hypodermic injector and ampule for intradermal, subcutaneous and intramuscular injection

Abstract

A needle free hypodermic injector comprising a hand manipulatable elongate housing, an impact impulse injection mechanism within the housing, a suction generating means within the housing and cooperable with the impact impulse injection mechanism, a safety interlock mechanism, at least one medicament containing ampule cooperable with the impact impulse injection mechanism and the suction generating means and having a jet orifice through which medicament is injectable through a skin surface in response to an impulse placed on the medicament by the impact impulse injection mechanism, and means to receive and hold the ampule on the injector in registration with the impact impulse injection mechanism and in communication with the suction generating means; whereby the injector is adapted to expel the medicament from the ampule in a jet stream of sufficient velocity to penetrate skin tissue held against the orifice by the suction generating means and to deposit the medicament intradermally, subcutaneously or intramuscularly based on the position and angle of the jet orifice.

Description

FIELD OF THE INVENTION [0001] This invention relates to a needle free, impact impulse injector device and disposable, single use, fillable or pre-filled, ampules therefor that are capable of delivering intradermal, (ID), subcutaneous (SUB-Q) and intramuscular (IM) injections in human or animal tissue by means of a thin high pressure liquid jet stream of sufficient velocity to penetrate the tissue of the recipient. The injector deposits medicament intradermally, or subcutaneously, or intramuscularly, utilizing the single use, disposable, medicament ampules that are designed to provide interfaces to the activation device, allowing easy installation by hand or mechanically from a multiple ampule dispensing apparatus, and providing exact positioning and sealing to the activation device structure. The ampules further contain features that induce a vacuum to stretch the skin, keeping the skin precisely aligned with the jet orifice for the short duration of the injection. The ampule's orif...

AI Technical Summary

Benefits of technology

[0015] The subject of the present invention represents an innovative approach to hypodermic needle-free injections, either Intradermal (ID), Subcutaneous (SUB-Q) or Intramuscular (IM), providing a process and a mechanization which contains disposable filled or prefilled medicament ampules and a manuallyor automatically operated activation device. There are many advantages covered by this invention. Above all, the injection uses horizontal impact impulse jet pressure, and thus it spreads the particles over a larger area than using a needle syringe, decreases the local pressure in the tissue, and eliminates leakage of the fluid from the opening in the tissue thereby reducing the possibility of spreading infections. The apparatus is capable of injection at any angle between horizontal and vertical in addition to laterally relative to the center line of the ampule, depending on the specific conditions of the medicament, injection site, etc. A unique feature of this invention is that the medicament is driven out of the ampule that holds it with a known and controlled impact impulse force.

[0016] A further innovation of the present invention is the process of the stretching of the skin, which increases permeability thus reducing the amount of energy required to inject fluid into a tissue, in conjunction with the injecting of the fluid horizontally to vertically and / or laterally into the skin which allows controlled positioning of the tissue for intradermal, subcutaneous or intramuscular injections. Also significant is the introduction of a safety feature built into the injector that will not allow operation until the skin is properly positioned.

[0019] A still further embodiment of the present invention provides an injector that is adapted to receive a multiple ampule assembly and a multiple ampule assembly therefor. The components and operation of the injector are substantially identical to those of the other embodiments except that the front end of the injector is modified to receive a rotatable, multiple ampule assembly, which assembly has a plurality of ampules arranged in a cylindrical cartridge. The cartridge is rotatable on the forward end of the injector so as to bring each ampule thereof into registration with the suction and injection means of the injector.

[0021] The present invention overcomes these deficiencies by the combination of the injector device and the ampule used therewith. The ampule is a key element of the system as it is the part which holds the medicament to be injected and interfaces with both the injector and the patient's skin surface to apply the suction generated by the injector in order to draw the skin tight for proper injection. The ampule further interfaces with the injector to provide proper functioning of the safety interlock since release of the interlock requires establishing a full suction on the system which cannot be achieved without the ampule. With the ampule and the injector combination of the present invention it is now possible to achieve needle-less injection of medicament intradermally, subcutaneously and intramuscularly at any angle relative to the skin surface. Furthermore, the ampule and injector combination of the present invention are capable of achieving the shallow intradermal injection necessary to accurately and reliably deliver medicament to the Langerhans cells in the upper spinosum layer of the skin.

[0024] The present invention still further provides a needle free hypodermic injector wherein the ampule further comprises at least one suction port extending vertically through the body from the upper surface to the lower surface at a point forward of the step face, the suction port being in fluid communication with the suction generating means whereby a suction generated by the suction generating means is applicable to the skin surface through the port to draw the skin surface upward against the lower surface of the ampule and the jet orifice prior to injection thereby stretching the skin to improve its porosity to the jet of medicament and, depending on the angle and placement of the orifice, to direct the jet of medicament intradermally, subcutaneously or intramuscularly.

[0026] The needle free hypodermic injector of the present invention further comprises at least one suction port vertically disposed through the ampule body forward of the jet orifice, a suction generating means disposed in the main body portion of the housing and suction conduits within the housing and the nose portion providing fluid communication between the suction generating means and the at least one suction port whereby suction generated by the suction generating means is conveyed to the at least one suction port of the ampule, the suction serving to draw the skin surface against the ampule and the orifice prior to injection. To improve the suction of the skin surface against the ampule and, preferably in the case of intradermal injection, to lift the skin surface slightly higher than the level of the jet orifice thereby providing an injection path to the spinosum layer of the skin, it is preferred that the lower surface of the ampule immediately surrounding the suction port be concave thereby forming a slight depression into which the skin is drawn by the suction.

Problems solved by technology

Present state of the art attempts to inject medications intradermally have met with only limited success due to the inherent difficulty associated with accurate positioning of the skin relative to the injector jet opening and the lack of precise control of the jet pressure vs. skin penetration when the injection is performed normal to the skin surface.

In addition, present systems lack precise control and repeatability of the injection jet velocity due to mechanical equipment tolerance variations within the pressure / force generators utilized.

Some present devices present safety concerns due to the lack of safety interlocks to prevent the device from being activated when not in proper contact with the skin, and catastrophic failures have been observed in the injector bodies in part caused by the lack of pressure control inherent in the device designs.

Such prior art devices result in substandard and painful injections because of this blasting action and the inability to address the variables of flow control once the skin is penetrated.

They are also deficient with respect to being able to provide the force necessary to penetrate the stratum corneum while restricting medicament delivery to the intradermal area generally and, specifically, the upper layers of the skin.

Typically, the use of existing devices results in loss of medicament at the nozzle entry point, poor injections on account of the recipient's movements or the operator's inexperience and receipt of the injection at an angle that either does not penetrate or penetrates too much for placement and dispersal of the medicament at the correct depth and layer of tissue.

In addition, premature operations are common, as well as relative movement between the epidermis and orifice which can cause tearing of the skin during injection, resulting in pain and poor transfer of the medicament to the recipient.

The need for medicament supply and personnel skill have produced problems for using these devices, for example, precisely measuring and controlling of the quantity of medicament administered and ensuring that the injector delivers the correct amount of medicament into the proper tissue.

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