WO2022175256A1

WO2022175256A1 - Hypodermic needle with sealing feature

Info

Publication number: WO2022175256A1
Application number: PCT/EP2022/053652
Authority: WO
Inventors: Henrik Bengtsson
Original assignee: Novo Nordisk A/S
Priority date: 2021-02-16
Filing date: 2022-02-15
Publication date: 2022-08-25

Abstract

A hollow needle is provided comprising a needle body having a through-going lumen and at least one bevelled end portion with an opening, and an elastomeric coating covering the at least one end portion and sealing the opening. A spacer volume which may be in the form of an air bubble is arranged in front of the opening. By this arrangement the bevelled end can cut through the coating with reduced risk of coring.

Description

HYPODERMIC NEEDLE WITH SEALING FEATURE

The present invention generally relates to a hypodermic needle having a bevelled end portion intended for subcutaneous introduction and being hollow to allow injection of a fluid drug for mulation. In a specific aspect the invention relates to a hypodermic needle provided with a seal coating. In the field of hypodermic needles sometimes the shorter term “needle” is used and sometimes the broader term “cannula” may be used.

BACKGROUND OF THE INVENTION

In the disclosure of the present invention reference is mostly made to hypodermic needles intended for use by a patient for subcutaneous administration of a fluid drug formulation, e.g. in the treatment of diabetes by delivery of insulin or a GLP-1 type drug, or in the treatment of growth disorders by delivery of growth hormone, however, this is only exemplary uses of the present invention.

Hypodermic needles for subcutaneous injection of medical drugs need to be kept sterile prior to use. For that reason replaceable needle units for drug injection devices and syringes with fixedly mounted needles have for many years been delivered with the needle or the entire unit inside a sealed enclosure (or wrapping) in which sterile conditions can be maintained.

Unwrapping and removing the protective enclosure from needle units and syringes require some efforts from the user and introduce several steps in preparing a device for injection. This increases the complexity of the task of administering an injection and to people with reduced eyesight and reduced motor skills, e.g., elderly people, the unwrapping, fitting and preparation may be difficult. The sterile wrapping is also responsible for a significant use of resources and materials that needs to be disposed of after use.

These problems can to some extend be mitigated by the introduction of a needle magazine solution. Such magazines can be mounted on the drug delivery device and comprise a plurality of needles adapted to be brought into fluid connection with a drug reservoir. However, hypo dermic needles inside needle magazines also need to be kept sterile prior to use, which com plicates the design and wrapping of a needle magazine. If the entire magazine is wrapped to maintain sterility, the sterile barrier is broken when the magazine is unwrapped and although a first hypodermic needle may be used immediately after the initial unwrapping, the remaining hypodermic needles in the magazine still need to be kept sterile. Magazines in which each hypodermic needle must be unwrapped by the user prior to use would be a very impractical solution. Thus, magazines are usually designed as sealed units, where the hypodermic needles are housed inside a sealed volume. This makes magazine design and production complicated, as the individual hypodermic needles need to exit the sealed, sterile volume during use without introducing an opening in the sterile barrier of the remaining hypodermic needles. Furthermore, the used hypodermic needle is usually returned to the magazine storage after use, whereby the now non-sterile hypodermic needle is accommodated inside the sealed volume, which ne cessitates the remaining hypodermic needles not yet used to be sealed from the used hypo dermic needles.

WO 2017/189162 discloses a needle magazine or needle unit comprising a plurality of nee dles, wherein each of the plurality of needles includes a first sterility barrier at a proximal end of the needle and a second barrier at a bevelled distal end of the needle. The sterility barriers are composed of e.g. a soft non-coring elastomer such as silicone, isoprene or butyl. By mov ing the needle in the proximal direction the proximal barrier is pierced, and by moving it in the distal direction the distal barrier is pierced. Other protective sleeves have been developed for hypodermic needles serving different purposes.

US 2004/0034318 discloses a device for withdrawal of blood comprising a hypodermic needle with a protective material, wherein the material to prevent contamination is fitted to the distal bevelled end of the needle. The material is illustrated as a plug sliding down the needle, as the needle pierces the material.

WO 2009/031144 discloses an arrangement comprising a syringe device, a needle, a sterile needle envelope (SNE) and a needle urging means (NUM) causing a relative longitudinal dis placement of a distal needle edge against a distal end of the SNE, when operation of the syringe device is initiated by e.g. a user of the syringe device. As a result of the longitudinal displacement the distal needle edge may perforate or fracture the distal SNE end. The SNE may be connected to reciprocating needle injecting means. In some embodiments of the in vention, the needle may be operatively coupled to a plunger of the syringe device, in a manner such that longitudinal displacement of plunger results in a longitudinal displacement of the distal needle edge towards the distal SNE end. Longitudinal displacement of distal needle edge towards distal SNE end may be accomplished e.g. by telescopically lengthening the needle, by longitudinally displacing the needle towards distal SNE end or by other suitable NUM. The longitudinal displacement causes the engagement of distal needle edge with distal SNE end whereby the distal needle edge and/or distal SNE end may be configured such that said en gagement results in a perforation of the distal SNE end.

US 5,290,254 discloses a shielded hypodermic needle assembly including a housing, a hollow hypodermic needle mounted in and extending from the housing and a tubular shield extending from the housing concentrically about the needle. The tubular shield is exposed to the envi ronment and is formed with a resilient longitudinally collapsible portion and a cap at the distal end of the tubular portion. As indicated, the tubular portion is of constant outside diameter and is disposed concentrically about the hollow needle and is of relatively thin thickness to permit longitudinal collapsing while being relatively thicker than the outside diameter of the needle to be protective. The cap is relatively rigid relative to the collapsible tubular portion and has an outside diameter greater than the outside diameter of the tubular portion. The cap has a T- shaped cross-section. In addition, the cap defines a transverse wall at the distal end of the shield in order to form a sealed chamber with the tubular portion in order to contain the needle therein in a sterile condition. The transverse wall is made of a thickness and of a material to permit penetration of the sharp end of the needle therethrough in response to longitudinal col lapsing of the tubular portion. The transverse wall is also of a nature to reseal in response to withdrawal of the needle therefrom, for example, upon expansion of the tubular portion.

US 9,682,197 discloses a similar solution using protective flexible sleeve with a rigid cap and an optimized distance between the outer diameter (OD) of the hypodermic needle and the inner diameter (ID) of the sleeve. While it is possible to reduce the distance between the ID of the silicone sleeve and the OD of the metal of the needle by a small, finite amount, if it is reduced to be much less than 0.00375 inches on each side, the resistance increases, and the amount of force for insertion also increases. With such small differences between the needle's outer diameter and the sleeve's inner diameter, there is also a tendency for the sleeve to roll in on itself, as opposed to collapsing, unless a second piece is secured to the tip to prevent this from happening, as in the dumbbell shaped version. Smaller distances between the sleeve and needle also become problematic because the production tolerances of the sleeve materi als ID and the needle OD can vary and can lead to contact, friction, and the need for more force for injection, particularly with the smaller needles and sleeve sizes. Similar solutions where a sleeve covers the needle are disclosed in GB 2 321 014, US 2014/0261861 , WO 2012/022810 and WO 2016/042162.

US 2,799,272 discloses a hypodermic needle guard comprising a rubber cap mounted on the needle distal and with an outer plastic sheath covering the rubber cap and extending proximally onto the needle stem. The rubber cap may be cylindrical with a distal opening being closed by the plastic sheath. The plastic sheath may be applied in a dipping process in which the plastic material enters the rubber cap distal opening thereby contacting or not contacting the needle tip.

Addressing the issue of providing an individually sealed hypodermic needle EP 20190891.0 discloses a method of applying a flexible coating on the distal bevelled portion of a hypodermic needle in a dipping and subsequent curing process. The coating is applied directly and the hypodermic needle and provides an initial adhesion between the coating and the hypodermic needle thereby sealing the distal portion of the hypodermic needle. The initial adhesion be tween the hypodermic needle and the coating can be irreversibly broken allowing the coating to be pushed proximally when during insertion the needle tip pierces the coating.

Having regard to the above, it is an object of the present invention to provide a hypodermic needle of the type comprising a flexible seal coating which is secure and reliable in use and which can be manufactured cost-effectively.

DISCLOSURE OF THE INVENTION

In the disclosure of the present invention, embodiments and aspects will be described which will address one or more of the above objects or which will address objects apparent from the below disclosure as well as from the description of exemplary embodiments.

The present invention is based on the realization that when a liquid substance is applied to an object with a very sharp edge and a narrow channel the liquid substance tends to be sucked into the narrow channel due to the capillary effect just as the surface tension of the liquid will prevent the liquid from following the contour of sharp edges on the object. Thus, dipping or spraying a fluid onto a hypodermic needle will result in the fluid entering the lumen where it will cure and plug the needle. Furthermore, the surface tension of the liquid will limit the bend radius of the outer surface of the liquid which may lead to the sharp edge of the hypodermic needle penetrating the liquid coating and leave the tip of the hypodermic needle unprotected. In the context of the present application the term coating denotes a layer of material spread over a surface, e.g. by dipping an object into a fluid material, or a layer of material applied to a surface by e.g. spraying or vapor depositing.

Once applied and cured, the hypodermic needle must also be able to penetrate the coating without cutting out a section of the coating material, which enters the lumen of the hypodermic needle (coring) that may prevent flow or be expelled by the flow and injected in the user’s skin. The coating must adhere to the hypodermic needle and seal airtight to the stem of the hypo dermic needle, while also being able to slide or fold back to allow a part of the hypodermic needle to be exposed and enter the user’s skin (front needle) or a septum (back needle).

Thus, in a first aspect of the invention a hollow needle is provided, comprising a needle body having a through-going lumen and at least one bevelled end portion with an opening, and an elastomeric coating covering the at least one bevelled end portion and sealing the opening, wherein a spacer volume is arranged in front of the opening and inside the elastomeric coating, whereby the bevel can cut through the coating without coring.

By this arrangement the bevelled end is allowed to cut into and penetrate the elastomeric coating with reduced risk of coring and thereby preventing full or partial blocking of the needle lumen. The needle may be oblong, straight or comprise one or more bends.

In a first exemplary embodiment the spacer volume is in the form of an amount of air in com munication with the lumen and being trapped in the coating in front of the opening.

In a second exemplary embodiment the spacer volume is in the form of an elastomeric plug member in which the bevelled end portion has been inserted sealing the opening, the elasto meric coating covering the plug member and the adjacent end portion.

The hollow needle may comprise a bevelled end portion at each end thereof, wherein at least one end portion comprises an elastomeric coating and a spacer volume as described above.

The hollow needle may comprise a sliding layer arranged between the needle body and the elastomeric coating allowing the elastomeric coating to be pushed away from the bevelled end portion sliding relatively to the needle body. The sliding layer may comprise a silicone oil.

In a second aspect of the invention a method of manufacturing a hollow needle of the type described above and comprising a spacer volume in the form of an amount of air is provided, comprising the steps of: (i) providing a hollow needle comprising a needle body having a through-going lumen, a naked bevelled first end portion with a first opening, and a second end portion with a second opening, (ii) sealing the second opening, (iii) dipping the first naked end portion liquid coating material, (iv) pulling the first end portion out of the liquid coating material, (v) suspending the hollow needle for an amount of time, (vi) allowing a drop of liquid coating material to form at the first end portion, e.g. by means of gravity, (vii) allowing an air bubble in communication with the lumen to form in the drop, and (viii) at least partially curing the coating material forming the drop thereby essentially preserving the shape and configuration of the drop and the enclosed air bubble.

In an exemplary embodiment the air bubble is created by influence of gravity and surface ten sion. Alternatively or additionally, the air bubble may be created by the influence of heating the air in the needle lumen.

After at least partially curing the coating material, the first end portion may be dipped in a liquid coating material again, this creating a second layer of coating material when the first end por tion is pulled out of the liquid coating material. Subsequently the one or more layers are cured or allowed to cure.

In a third aspect of the invention a method of operating a sealed hollow needle is provided, comprising the steps of providing a sealed hollow needle as described above, arranging the distal end of the sealed hollow needle against a supporting surface, and advancing the bev elled end portion through the elastomeric coating, the elastomeric coating thereby being pushed away from the bevelled end portion sliding relatively to the needle body.

The supporting surface comprises an opening through which the bevelled end portion is ad vanced, e.g. a drug delivery device comprising a distal cap portion with an opening through which the bevelled end portion is advanced.

Alternatively the supporting surface may be penetratable by the bevelled end portion, e.g. in the form of a skin surface of a subject.

In a further aspect of the invention a hollow needle is provided, comprising a needle body having a through-going lumen and at least one bevelled end portion with an opening, an elas tomeric coating covering the at least one end portion and sealing the opening, and a sliding layer arranged between the needle body and the elastomeric coating allowing the elastomeric coating to be pushed away from the bevelled end portion sliding relatively to the needle body. The sliding layer may comprise a silicone oil.

The elastomeric coating and the sliding layer may be configured such that the elastomeric coating disengages from the needle body over its entire length when the needle is introduced subcutaneously, this allowing the elastomeric coating to be pushed proximally in its entirety and in sliding engagement with the needle.

Alternatively, the elastomeric coating and the sliding layer may be configured such that the elastomeric coating progressively disengages from the needle surface when the needle is in troduced subcutaneously, this providing a radially oriented accordion-like folding displacement of the elastomeric coating.

How the elastomeric coating is displaced from the needle surface will depend on a number of properties which, depending on the design objects, can be decided during a normal design procedure, e.g. the type of materials and the thickness of the layers.

As used herein, the term "drug" is meant to encompass any drug-containing flowable medicine capable of being passed through a delivery means such as a hypodermic needle in a controlled manner, such as a liquid, solution, gel or fine suspension. The drug may have a blood glucose controlling effect, e.g. human insulin and analogues thereof as well as non-insulins such as GLP-1 and analogues thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following embodiments of the invention will be described with reference to the drawings, wherein fig. 1 A shows the distal end of a hypodermic needle after having been dipped in a liquid coating material, fig. 1B shows the hypodermic needle of fig. 1A after an air bubble has formed, fig. 1C shows the hypodermic needle of fig. 1 B after a second layer of a liquid coating material has been added, figs. 2A and 2B show for the figs. 1A-1C embodiment how the coating is sliding proximally along its entire length, figs. 3A and 3B show for the figs. 1A-1C embodiment how the coating is folding radially as it progressively is pushed proximally, fig. 4A shows the distal end of a hypodermic needle provided with a spacer member right after having been dipped in a liquid coating material, fig. 4B shows the hypodermic needle of fig. 4A after having been turned upside-down, figs. 5A and 5B show for the figs. 2A-2B embodiment how the coating is sliding proximally along its entire length together with the spacer member, figs. 6A and 6B show for the figs. 2A-2B embodiment how the coating is folding radially as it progressively is pushed proximally together with the spacer member, and figs. 7A-7C show in different states of use a needle unit comprising four coated hypodermic needles.

In the figures like structures are mainly identified by like reference numerals.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

When in the following terms such as “upper” and “lower”, “right” and “left”, “horizontal” and “vertical” or similar relative expressions are used, these only refer to the appended figures and not necessarily to an actual situation of use. The shown figures are schematic representations for which reason the configuration of the different structures as well as their relative dimensions are intended to serve illustrative purposes only. When the term member or element is used for a given component it generally indicates that in the described embodiment the component is a unitary component, however, the same member or element may alternatively comprise a number of sub-components just as two or more of the described components could be provided as unitary components, e.g. manufactured as a single injection moulded part. The term “as sembly” does not imply that the described components necessarily can be assembled to pro vide a unitary or functional assembly during a given assembly procedure but is merely used to describe components grouped together as being functionally more closely related.

With reference to figs. 1-3 a first embodiment (FE) of a manufacturing process for a coated needle corresponding to aspects of the present invention will be described.

Step 1 FE: A hypodermic needle 100 prepared with a bevelled distal end 112 is submerged in a mixture of silicone oil and an appropriate solvent. Dow Corning® 360 is already used as a friction reducing coating on hypodermic needles for injection devices being combined with sol vent Dow Corning® OS-10. The hypodermic needle is then lifted out of the DC360/OS10- mixture and excess silicone oil and solvent are blown out of the hypodermic needle lumen and off the external surface using compressed air. The thickness of the layer of silicone oil on the hypodermic needle depends on the amount of solvent mixed in the oil. The more solvent in the oil, the thinner the remaining layer of oil will be on the hypodermic needle. The solvent evapo rated within a few seconds after the hypodermic needle is lifted out of the oil/solvent mixture. Step 2 FE: The proximal rear end of the needle is now plugged (unless the rear end has already been coated in a prior coating process sequence) to thereby limit the amount of coating to be sucked into the hypodermic needle due to capillary effects.

above the grinded area. One example of a suitable coating material is Silpuran® 6000-05 from Wacker Chemie AG, which means it is a material of the Silpuran® 6000-series with a Shore hardness of 5A which is about where materials go from being referred to as “Soft” to “Extra Soft” or about midway between a gel shoe insole and a normal rubber band.

The liquid coating material must be free from air bubbles during the dipping of the hypodermic needle which may be obtained by centrifuging the liquid coating material prior to dipping, how ever, air bubbles may be introduced into the liquid coating material again if hypodermic needles are inserted in the liquid coating material at too high velocity. Some liquid coating material 132 will enter the opening of the hypodermic needle and rise above the opening inside the hypo dermic needle driven by both the hydrostatic pressure and the capillary effect caused by the surface tension of the liquid and the narrow channel, however, this will be countered by the pressure rising in the very small volume of trapped air inside the plugged hypodermic needle, this resulting in only a very small amount of liquid entering the hypodermic needle.

Step 4 FE: The hypodermic needle is subsequently lifted out of the liquid coating material with a layer of liquid coating material 130 adhering to the surfaces of the hypodermic needle. As the cannula is pulled out of the liquid coating material the gravity will cause some of the liquid to flow down along the inner- and outer surfaces of the cannula. As it is commonly known from fluid mechanics the velocity of a liquid flowing along a solid surface is zero at the surface and increases with the distance from the surface. Thus, the liquid runs down faster further from the surface than near the surface, which means that the liquid running down the inside and outside of the hypodermic needle will not run on the surface at all, but run faster, the further from the surface the liquid is. This means that the longer time it runs, the thinner and not shorter, the layer will become.

Hence, the slower the hypodermic needle is pulled out of the liquid coating material, the thinner the layer of coating material remaining on the hypodermic needle will be, until the hypodermic needle is pulled out so slowly, that the layer becomes so thin, that flow stops because the gravitational forces on the liquid film is countered by the surface tension of the liquid. As the tip of the hypodermic needle leaves the surface of the liquid coating material, the surface tension of the liquid material will shape the liquid adhering to the hypodermic needle in a drop like shape 131 as shown in fig. 1A.

If the hypodermic needle is pulled out of the liquid too fast, more liquid than can be carried by the surface tension of the liquid will run down and increase the diameter of the ball-shaped end of the drop-like liquid material at the end of the hypodermic needle. When the gravity exceeds the surface tension, a drop will snap off and fall from the liquid material on the hypo dermic needle, this reducing the thickness of liquid coating on the hypodermic needle.

As it can be understood from the above, the upper and lower limits of the thickness of the coating layer and the diameter of the ball-shaped lower part of the drop-like liquid material on the hypodermic needle depends on the surface tension and density of the liquid coating mate rial. The actually obtained thickness and diameter of the drop-like shaped liquid coating mate rial on the hypodermic needle is determined by the velocity by which the hypodermic needle is pulled out of the coating liquid. In most cases, the viscosity and surface tension of the coating liquid will result in the tip 113 of the hypodermic needle penetrating the liquid and thereby be left exposed as shown in fig. 1A.

As the hypodermic needle is lifted out of the liquid coating material, the hydrostatic pressure inside the hypodermic needle drops and reverses as the coating liquid on the hypodermic needle separates from the liquid reservoir. Gravity pulls down the liquid on the outer and inner surface of the hypodermic needle until a state of equilibrium with the surface tension is reached. This expands the air trapped inside the plugged hypodermic needle and the coating liquid inside the hypodermic needle runs down, adding the weight of liquid suspended by the surface tension, further expanding the air inside the hypodermic needle. The air, which is es sentially being sucked out by the weight of the liquid, creates a spacer volume in the form of an air bubble 133 or void at the opening 101 of the hypodermic needle lumen (see fig. 1 B), whereby it is avoided that a section is cut out of the coating by the inner edge of the opening and block the hypodermic needle, during penetration of the coating.

Step 5 FE: The tip of the hypodermic needle with the coating liquid on is subsequently placed in a heat well for about two seconds, whereby the coating liquid cures partially, but not fully. The coating is not fully cured, but is solidified sufficient to not change shape or drip off. The hypodermic needle is now sealed by a solid coating in the coating end. Step 6 FE: The plug in the rear end (opposite the coated distal end) can now be removed. The removal of the plug may be postponed to after the second dipping of the hypodermic needle (see below), but must be performed prior to final heating and curing, to avoid air trapped inside hypodermic needle expands and push coating of or puncture of coating due to excessive pres sure.

again, this time to the depth corresponding to the length required to be coated.

As was the case with the first coating layer the thickness of the second coating layer 135 and the diameter of the drop-like shape 136 of the coating is determined by the velocity at which the hypodermic needle is pulled out of the coating liquid. As shown in fig. 1C the second coat ing layer now fully covers the distal-most pointed end of the hypodermic needle.

Step 9 FE: The coated needle is subsequently arranged in a heat well again for curing. If this second layer is the final layer, the heat is applied for about 30 seconds to fully cure the coating. If a third layer of coating is to be applied, the heat application in the heat well may be reduced to allow better bonding between the coating layers.

Steps 10-12 FE: If a third layer of coating is to be applied, steps 7-9 are repeated as steps IQ- 12, but only the last heating to cure the coating is applied for a sufficient time to ensure com plete curing and bonding between the layers.

Alternative steps 4-7 FE: As an alternative to steps 4-7 FE in the procedure described above, the hypodermic needle can be heated by induction while the distal end is inserted in the coating liquid. The heat induced in the stainless steel material of the hypodermic needle will heat the small amount of air inside the hypodermic needle and it will expand and push out any coating liquid inside the hypodermic needle and create a small air bubble at the opening of the lumen, whereby coring and plugging can be prevented.

The heated hypodermic needle will also heat the surrounding coating material, but slower than the air inside the hypodermic needle due to the larger specific heat capacity of the coating liquid. Consequently the coating liquid will start curing from the hypodermic needle surface and outwards. In this case, the thickness of the (first) layer is not determined by the velocity of which the hypodermic needle is pulled out of the coating liquid, but by the temperature to which the hy podermic needle is heated and the length of time it is heated while inserted in the coating liquid. The resulting coating will not be drop-like shaped but essentially cylindrical.

The hypodermic needle may then be lowered to a position at which the entire length to be coated is submerged in the coating liquid and additional heat applied by induction or the hypo dermic needle may be placed at this depth from the start.

However, once being pulled out of the coating liquid, some liquid coating material will adhere to the coating and thus form a drop-like shape of the partially liquid coating. As the majority of the liquid material will be placed at the bottom with very little stainless steel hypodermic needle material present, this liquid coating material will most probably best be cured in a heat well or by heated airflow, just as the second layer described in the procedure above.

The plug in the rear end (opposite the coated end) should be removed prior to final heating for curing, to eliminated risk of heated air inside hypodermic needle expands and blow of coating or puncture coating due to excessive pressure.

Examples of the first embodiment: Fig. 2A shows in an initial sealed state a hypodermic needle 100 with a relatively thick coating 130 and a low amount of OS-10 in the silicone oil, such a configuration being intended for longitudinal displacement of the coating 130 as illustrated in fig. 2B in which the seal coating along its entire length is pushed proximally in sliding engage ment with the hypodermic needle corresponding to the hypodermic needle being inserted sub cutaneously.

Fig. 3A shows in an initial sealed state a hypodermic needle 100 with a relatively thin coating 140 and a higher amount of OS-10 in the silicone oil, such a configuration being intended for a radially oriented accordion-like folding displacement 141 of the coating in which the coating progressively disengages from the hypodermic needle surface as shown in fig. 3B.

With reference to figs. 4-6 a second embodiment (SE) of a manufacturing process for a coated needle corresponding to aspects of the present invention will be described.

Step 1 SE: The hypodermic needle 100 is siliconized as in step 1 described above for the first embodiment. Step 2 SE: The hypodermic needle is plugged in the distal end (the end to be coated) such that the tip of the needle is completely covered including the opening 101 of the hypodermic needle and the bevelled grinded area and extending about 0.5 - 1 mm above the grinded area. The plug 105 may e.g. be spherical or cylindrical.

Plugs may be pre-manufactured using the same material as the later applied liquid coating material, e.g. Silpuran® 6000 as described above in respect of the first embodiment. Plugs may also be made of thermoplastic elastomers (TPE) containing immobilised zinc (Zi⁺⁺) or immobilised silver (Ag⁺). These ions are known to inhibit micro-bacterial growth and may pro vide an additional safeguard to ensure sterility. The main properties of importance are com patibility with the coating material in regards to adherence, flexibility and hardness.

liquid to the depth corresponding to the length required to be coated.

Step 4 SE: The coated hypodermic needle is then pulled out of the liquid coating material leaving a layer 150 of coating. As the plug on the hypodermic needle distal end will be signifi cantly larger in circumference than the hypodermic needle in order to be able to properly re ceive and seal the hypodermic needle distal end, the plug will carry some excess liquid coating material on the top and sides. The excess liquid coating material starts to run down and form a drop-like shape 151 underneath the plug as shown in fig. 4A. Due to the increased surface area of the plug this drop-like shape will be much larger than if the hypodermic needle was not plugged in the end to be coated .

the hypodermic needle is turned upside-down whereby the liquid coating material will start to flow over the plug and run down the stem of the hypodermic needle as shown in fig. 4B, this adding to the thickness of the coating along the hypodermic needle stem. As shown a collar 152 of coating material will typically form of at the proximal end of the coated portion.

Step 6 SE: The coated needle is subsequently placed upside-down in a heat well for curing. If the first layer is the final layer the heat is applied for about 30 seconds to fully cure the coating. If a second layer of coating is to be applied, the heat application in the heat well may be re duced to allow better bonding between the coating layers. Examples of the second embodiment: Fig. 5A shows in an initial sealed state a hypodermic needle 100 with a relatively thick coating 160 and a low amount of OS-10 in the silicone oil, such a configuration being intended for longitudinal displacement of the coating as illustrated in fig. 5B in which the seal coating along its entire length and together with the somewhat flattened plug 105 is pushed proximally in sliding engagement with the hypodermic needle corresponding to the hypodermic needle being inserted subcutaneously.

Fig. 6A shows in an initial sealed state a hypodermic needle 100 with a relatively thin coating 160 and a higher amount of OS-10 in the silicone oil, such a configuration being intended for a radially oriented accordion-like folding displacement 161 of the coating in which the coating progressively disengages from the hypodermic needle surface as shown in fig. 6B.

With reference to figs. 7A-7C an embodiment of a needle assembly (or magazine) 200 with four coated hypodermic needles 100 will be described, such a needle assembly being suitable for use in combination with the above-disclosed coated hypodermic needles (in the following also needles). The figures illustrate only components necessary for explaining the integration of the coated needles into the needle assembly and for integrating or connecting the needle assembly to a drug delivery device device. The figures also illustrate operation of the coated needles.

The needle assembly 200 is shown in three different states during operation. Although not shown the needle assembly 200 may also comprise a shield and a shield guide. Alternatively, the shield and the shield guide may be integrated as parts of an injection device designed to be used in combination with the needle assembly 200. In some alternatives the needle assem bly or the injection device may also comprise a distal plate with apertures or a distal septum allowing the needle to pass and to compress the coating, whereby only needles are allowed to pass the apertures or septum and enter the skin. Alternatively, the distal end of the injection device is open or can be opened and the coating is adapted to be moved proximally when engaging a skin surface during needle insertion.

Fig. 7A shows the needle assembly 200 in a first state and in combination with drug cartridge 300 comprising a needle-pierceable distal septum 310. The needle assembly comprises a plu rality (here: four) of distally coated hypodermic needles 100 arranged in a needle unit housing 220 with a proximal end 221 and a distal end 222. The housing 220 comprises a plurality of channels corresponding to the plurality of coated hypodermic needles 100. The coated hypo dermic needles are positioned in the channels and the channels are adapted to guide the coated hypodermic needles during proximal and distal movement thereof. Each of the hypo dermic needles 100 are fixed in a needle holder 230 which is slidably arranged in the housing 220. At the proximal end 221 the housing 220 comprises a hub portion 225 adapted to receive and engage the cartridge 300. In the shown state the proximal non-coated end 111 of each of the hypodermic needles has pierced the cartridge septum when the needle assembly was engaged to the cartridge. The needles have therefore established fluid communication with the drug in the cartridge 300. The distal end portion 112 with the bevelled sharp distal end of each needle is covered by a coating 130. One of the needles is shown with a transparent coating 130 allowing the distal bevelled end to be visible. The coating may be compressed by the skin of the subject or by a not shown plate with apertures.

Fig. 7B shows the needle assembly 200 in a second state, wherein one of the four coated hypodermic needles 100 has been moved in a distal direction by a needle operating mecha nism (not shown). As appears, the coating 130 has been pushed proximally relatively to the needle body, e.g. when being moved distally through an opening in a distal portion of the nee dle assembly, and compressed in an accordion-like style, the distal end portion 112 of the hypodermic needle extending from the compressed coating 130.

Fig. 7C shows the needle assembly 200 in a third fully used state in which all four hypodermic needles 100 are positioned in a retracted position with the coating 130 in a compressed prox imal position. Each of the coatings 130 has been compressed by sequentially moving each of the coated hypodermic needles distally through a skin surface to a subcutaneous injection position, thereby axially compressing the coating 130, injecting an amount of drug formulation subcutaneously through the needle, and retracting the coated needle to the proximal position. This procedure is repeated until all of the four coated hypodermic needles have been used. The needle assembly will normally be provided with a mechanism preventing a hypodermic needle to be used again.

In the above description of exemplary embodiments, the different structures and means provid ing the described functionality for the different components have been described to a degree to which the concept of the present invention will be apparent to the skilled reader. The detailed construction and specification for the different components are considered the object of a nor mal design procedure performed by the skilled person along the lines set out in the present specification.

_*****

Claims

1. A sealed hollow needle comprising: a needle body (100) having a through-going lumen and at least one bevelled end portion with an opening, and an elastomeric coating (130) covering the at least one end portion and sealing the opening, wherein a spacer volume (105, 133) is arranged in front of the opening and inside the elasto meric coating, whereby the bevelled end can cut through the coating without coring.

2. A sealed hollow needle as in claim 1 , wherein: the spacer volume is in the form of an amount of air (133) in communication with the lumen and being trapped in the coating (131) in front of the opening.

3. A sealed hollow needle as in claim 1 , wherein: the spacer volume is in the form of an elastomeric plug member (105) in which the bevelled end portion has been inserted thereby sealing the opening, the elastomeric coating (150) covering the plug member and the adjacent end portion.

4. A sealed hollow needle as in any of claims 1-3, wherein: the hollow needle comprises a bevelled end portion at each end thereof, and at least one end portion comprises an elastomeric coating (130) and a spacer volume (105, 133).

5. A sealed hollow needle as in any of claims 1-4, further comprising: a sliding layer arranged between the needle body and the elastomeric coating allow ing the elastomeric coating to be pushed away from the bevelled end portion sliding relatively to the needle body.

6. A sealed hollow needle as in claim 5, wherein: the sliding layer comprises a silicone oil.

7. A sealed hollow needle as in any of claims 1-6, wherein: the coating comprises at least two coating layers (130, 135).

8. A method of manufacturing a sealed hollow needle, comprising the steps of: providing a hollow needle comprising a needle body having a through-going lumen, a naked bevelled first end portion with a first opening, and an opposed second end portion with a second opening, sealing the second opening, dipping the first end portion in a liquid coating material, pulling the first end portion out of the liquid coating material to thereby create a layer of coating material, suspending the hollow needle for an amount of time, allowing a drop of liquid coating material to form at the first end portion allowing an air bubble in communication with the lumen to form in the drop, and at least partially curing the coating material forming the drop thereby essentially pre serving the shape and configuration of the drop and the enclosed air bubble.

9. A method of manufacturing a hollow needle as in claim 8, wherein the air bubble is created by influence of gravity and surface tension.

10. A method of manufacturing a hollow needle as in claim 9, wherein the air bubble is increased by the additional influence of heating the air in the needle lumen.

11. A method of manufacturing a hollow needle as in claim 8, wherein the air bubble is created by heating the air in the needle lumen.

12. A method of manufacturing a sealed hollow needle as in any of claims 8-11, compris ing the further step of: after at least partially curing the coating material, dipping the first end portion in a liquid coating material, and pulling the first end portion out of the liquid coating material to thereby create a second layer of coating material.

13. A method of operating a sealed hollow needle, comprising the steps of: providing a sealed hollow needle as in any of claims 1-7, arranging the distal end of the sealed hollow needle against a supporting surface, and - advancing the bevelled end portion through the elastomeric coating, the elastomeric coating thereby being pushed away from the bevelled end portion sliding relatively to the nee dle body.

14. A method as in claim 13, wherein the supporting surface comprises an opening through which the bevelled end portion is advanced.

15. A method as in claim 13, wherein the supporting surface is penetratable by the bev elled end portion.