Intradermal needle

Abstract

An intradermal needle assembly that is attachable to a prefillable container intended for intradermally injecting substances into an animal includes a needle cannula supported by a hub portion. The hub portion is adapted to receive the prefillable container just prior to administering the intradermal injection. A limiter portion surrounds the needle cannula and extends away from the hub portion toward a forward tip of the needle cannula, and includes a skin engaging surface with the needle cannula having a fixed angle of orientation, preferably generally perpendicular, relative to the plane of the skin engaging surface. The skin engaging surface is received against the skin of an animal to administer an intradermal injection. The forward tip extends beyond the skin engaging surface a distance enabling penetration of the needle cannula into the dermis layer of the skin of the animal enabling injection of the substance into the dermis layer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a Continuation of U.S. patent application Ser. No. 09 / 834,438, filed on Apr. 13, 2001, which is a continuation-in-part of U.S. patent application Ser. No. 09 / 417,671, filed on Oct. 14, 1999, now U.S. Pat. No. 6,494,865. FIELD OF THE INVENTION [0002] The present invention generally relates to a needle assembly attachable to a prefillable container for delivering substances such as drugs, vaccines and the like used in the prevention, diagnosis, alleviation, treatment, or cure of disease into the skin of an animal using an injection device having a needle cannula and a limiter for engaging the surface of the skin and limiting penetration of the tip of the needle cannula into the skin. Preferably, the limiter limits penetration of the needle cannula from approximately 1.0 mm to approximately 2.0 mm, and most preferably around 1.5 mm±0.2 mm to 0.3 mm, such that the substance is injected into the dermis layer of the animal...

AI Technical Summary

Benefits of technology

[0008] In contrast to the conventional needle assembly and delivery method discussed above, it has been found by the applicant that intradermally injecting substances into the skin can be performed in connection with the use of the present invention to effectively and reliably deliver such substances intradermally.

[0018] In the preferred embodiment of the assembly, the hub portion and the limiter portion are formed as separate pieces, with the limiter portion defining an inner cavity receiving at least a portion of the hub and including an abutment engaging a corresponding structure on the hub portion thereby limiting the length of the needle cannula extending beyond the skin engaging surface.

[0021] In the preferred embodiment, the limiter comprises a non-elastomeric polymer, with the skin engaging surface including an elastomeric polymer being circumscribed by the non-elastomeric polymer. The elastomeric polymer may be pierced by the needle cannula when the limiter is mated to the hub portion. Also, the forward end the needle cannula includes a beveled tip ranging in length between approximately 0.8 mm and 1.0 mm, and approximately 0.9 mm. In addition, the enclosure means comprises a needle plunger inserted through the limiter and being depressable for bending the needle cannula thereby retracting the needle cannula into the limiter, with the needle plunger oriented generally perpendicular to the needle cannula. Further, a cap is attachable to the skin engaging surface for concealing the forward tip, with the cap comprising an elastomer and the forward tip insertable into the elastomer to thereby sealing the needle cannula and prevent the substance from leaking from the prefillable container through the cannula.

Problems solved by technology

Therefore, a needle cannula that penetrates the skin deeper than about 3.0 mm has a potential of passing through the dermis layer of the skin and making the injection into the subcutaneous region, which may result in an insufficient immune response, especially where the substance to be delivered intradermally has not been indicated for subcutaneous injection.

Also, the needle cannula may penetrate the skin at too shallow a depth to deliver the substance and result in what is commonly known in the art as “wet injection” because of reflux of the substance from the injection site.

Due to the inherent limitations of the standard needle assembly, the standard procedure for making an intradermal injection is known to be difficult to perform, and therefore dependent upon experience and technique.

Accordingly, the technique utilized to perform the standard intradermal injection is difficult and requires the attention of a trained nurse or medical doctor.

Inserting the needle to a depth greater than about 3.0 mm typically results in a failed intradermal injection because the substance being expelled through the cannula will be injected into the subcutaneous tissue of the animal.

A further cause of error is derived from pinching rather than stretching the skin in the area of the injection, which is normally done when giving a subcutaneous rather than an intradermal injection.

Procedural errors as described above result in delivering the contents of the injection into the subcutaneous layer, which can reduce the effectiveness of the injection, as well as possibly deliver the substance in a way not approved for delivery.

Intradermal injections performed by using the standard procedure also are known to cause a significant amount of pain to the recipient of the injection because the needle cannula is inserted into the skin at an angle of about fifteen degrees.

This results in a significant disruption of the pain receptors dispersed throughout the upper layers of the skin.

Also, self-administered intradermal injections are not possible using the present method.

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