BACKGROUND

An injected therapeutic typically has a designated injection route that is dependent on such factors as the timescale of the drug action, the dosage frequency, the required absorption rate for intended effect, and the target location(s). In particular, the subcutaneous (SC) space is considered to be useful for a number of applications and indications. When injecting into the SC space, ensuring that the injectate does not pass through the SC layer and into deeper layers is desirable because further penetration may reduce treatment efficacy, cause patient discomfort or pain, and damage internal tissue. There remains a need for needle-free injection guides that mitigate risks of over-penetration or under-penetration during needle-free injection into the subcutaneous space.

SUMMARY

An injection guide globally aligns an injector to an angle selected for consistent subcutaneous delivery of an injectate, while locally aligning a patient's skin normal to the injection path at the location where the injection pierces the skin. This arrangement advantageously maintains controlled contact between an injector and a subject's skin in order to deliver the full, intended volume of injectate into the patient's subcutaneous layer while avoiding misdelivery into adjacent layers such as the patient's dermis or muscle.

In a general aspect of the invention, an injection guide is used with a needle-free injector for administering an injectable substance to a target underlying a contact surface. The injection guide is configured to position the needle-free injector relative to the contact surface and includes a surface positioner configured to be disposed at a distal end of the needle-free injector. The surface positioner has an axis extending from a first end of the surface positioner to a second end of the surface positioner. The surface positioner includes an outer surface having a first section for gripping a first portion of the contact surface, the first section disposed at an acute angle relative to the axis and a second section having an opening configured to be spaced from a nozzle of the needle-free injector and for passing the injectable substance from the nozzle to the contact surface.

In another aspect, an injection guide disclosed herein includes an entrance to receive a stream of injectate from a needle-free injector, an exit for passage of the stream into a contact surface, and a passageway linearly coupling the entrance to the exit along an axis of travel for the stream of injectate through the injection guide. The injection guide may further include a first alignment surface providing a substantially planar region disposed at an acute angle to the axis, along with a second alignment surface positioned about the exit of the injection guide, the second alignment surface configured to locally orient the contact surface at a second angle to the axis different from the acute angle in a region about the exit.

Aspects may include one or more of the following features.

The second section of the surface positioner may be configured to depress and deform a second portion of the contact surface, such that the second portion is at a selected angle relative to the first portion of the contact surface. The selected angle may be between 5 degrees and 85 degrees, or the supplements thereof. The first section of the surface positioner may be in the form of an arcuate band. The section portion of the surface positioner may be in the form of a cylindrical tube having a taper. The arcuate band may be in the form of an ellipse having a major axis and a minor axis, the cylindrical tube positioned at a vertex along the major axis of the ellipse.

In another general aspect, a needle-free injector is configured for administering an injectable substance to a target underlying a contact surface. The needle-free injector has a distal end and includes a surface positioner disposed at the distal end of the needle-free injector. The surface positioner has an axis extending from a first end of the surface positioner to a second end of the surface positioner. The surface positioner includes an outer surface having a first section for gripping a first portion of the contact surface, the first section disposed at an acute angle relative to the axis, and a second section having an opening spaced from a nozzle of the needle-free injector for passing the injectable substance from the nozzle to the contact surface.

Aspects may include one or more of the following features.

The second section of the surface positioner may be configured to depress and deform a second portion of the contact surface such that the second portion of the contact surface is at a selected angle relative to the first portion of the contact surface. The selected angle may be between 5 degrees and 85 degrees, or the supplements thereof. The first section of the surface positioner may be in the form of an arcuate band. The second section of the surface positioner may be in the form of a cylindrical tube having a taper. The arcuate band may be in the form of an ellipse having a major axis and a minor axis, the cylindrical tube positioned at a vertex along the major axis of the ellipse.

In another general aspect, a method of using a needle-free injecting injector to administer an injectable substance to a target underlying a contact surface, the needle-free injector having a longitudinal axis includes positioning a first section of the needle-free injector at an acute angle relative to the longitudinal axis of the needle-free injector, gripping with the first section of the needle-free injector a first portion of the contact surface, and injecting the injectable substance to the contact surface through an opening at a second section of the needle-free injecting instrument, the opening spaced from a nozzle of the needle-free injector.

Aspects may include one or more of the following features.

The method may include using the second section of the needle-free injector to depress and deform a second portion of the contact surface such that the second portion of the contact surface is at a selected angle relative to the first portion of the contact surface. The selected angle may be between 5 degrees and 85 degrees, or the supplements thereof. The method may include forming the first section of the needle-free injector as an arcuate band. The method may include forming the second section of the needle-free injector as a cylindrical tube having a taper. The method may include forming the arcuate band in the form of an ellipse having a major axis and a minor axis, and positioning the cylindrical tube at a vertex along the major axis of the ellipse.

Aspects may have one or more of the following advantages.

Among other advantages, a needle-free injector having the above features increases the likelihood that the injectable substance is delivered into the subcutaneous layer and not into surrounding tissue layers, such as the dermis and muscle layers. The surface positioner includes an outer surface that grips the contact surface (i.e., skin) of the subject so that the injectable substance passing through the nozzle is injected through the epidermis and dermis and into the subcutaneous space. Gripping the contact surface stabilizes and maintains the position of the needle-free injector and prevents it from rocking from side to side. That is, in the event of relative movement (e.g., due to movement of the subject), the target remains fixed relative to the needle-free injector.

In certain embodiments, a section of the positioner also depresses and deforms a localized area of the contact surface such that the nozzle through which the injectable substance is injected at a substantially 90° angle relative to the contact surface. By injecting the substance at such an angle, the ability to maintain the substance within the subcutaneous layer is maximized and the risk of the injectable substance passing through to the adjacent tissue is minimized. In essence, by positioning the nozzle at an acute angle relative to the contact surface and then deforming a localized area of the contact surface such that the injection site is parallel to the nozzle (i.e., the injectable substance pierces the injection site at a 90° angle), the injectable substance is introduced along the subcutaneous layer rather than transverse to the layer. This approach for introducing the injectable surface is particularly advantageous because physical characteristics (i.e., thickness, hardness, elasticity, composition) vary from subject to subject. It is appreciated that although a 90° angle is preferable, there is still benefit to injecting the substance at angles offset from 90° (e.g., in a range between 5° and 85°, or the supplements thereof).

Other features and advantages of the invention are apparent from the following description, and from the claims.

