Patent Description:
Syringes, in particular those pre-filled, are widely used to inject, in a person, medicinal products such as, among others, anticoagulants, for example heparin and the like, vaccines, small sized molecules, and cosmetic products, for example hyaluronic acid.

They represent a growing market, as they make it possible to effectively reduce errors in the dosage of a product to be injected and contribute to reduce packaging costs.

A syringe typically comprises a transparent cylindrical body, on which measurement marks are shown, a plunger sliding inside the transparent cylindrical body and a hollow and frusto-conical tip, extending from the transparent cylindrical body and onto which a needle, it also being hollow, is then fitted through which the product to be injected contained in the hollow cylindrical body passes. The plunger is provided, at one of the ends thereof, with a rubber ring or capsule to ensure the controlled and constant sliding of the plunger inside the transparent cylindrical body. The tip of the syringe can be provided with a Luer-lock connector, i.e. a screwing system that locks the needle connection to prevent the unintentional removal thereof. Finally, the syringe is provided with a closure cap, the main function of which is to prevent the product contained in the syringe from leaking.

The closure caps of the syringes with Luer-lock connector, in addition to having sealing properties, i.e. ensuring air tightness, and anti-screwing properties, i.e. being configured so that they do not accidentally and undesirably separate from the syringe when the syringe is not in use, typically during syringe storage, must also ensure that the product contained in the syringe is not tampered with, either accidentally or intentionally, prior to use. In fact, it is essential that the closure cap is only removed from the syringe when it is being used by a healthcare professional to inject a person with the product contained in the syringe. This is done in order to preserve the product, avoiding the introduction or removal of substances other than those with which the syringe is e.g. pre-filled during production, into/from the syringe during transport and storage thereof.

A syringe provided with a tamper-proof cap is disclosed in the patent document no.

The syringe comprises a hollow body having a neck centred on an axis, an elastomeric cap, which is inserted into the neck and having an end projecting axially from the neck, and a stiffening sleeve, which is mounted on the cap and on the neck and having a collar mounted around the projecting end of the cap and itself projecting axially forward with respect to the cap. The syringe also comprises an elastomeric cap, which is inserted into the collar, a protective cap, which is mounted on the sleeve and on the cap and having a rear terminal edge, and a ring, which is snap-fittingly fixed on the sleeve and having a front terminal edge facing the rear terminal edge of the protective cap. The rear terminal edge of the protective cap and the front terminal edge of the ring fixed to the sleeve are connected therebetween by a frangible connection, so that the cap is held in place on the syringe body. The cap is thus only removable from the syringe body after the frangible connection has been broken.

However, the tamper-proof syringe system described above has some drawbacks. In particular, this known system is not able to guarantee to the healthcare professional the total absence of tampering with the cap, and therefore the integrity of the product contained in the syringe. In fact, due to the presence of the snap-fitting coupling between the ring, to which the protective cap is connected by the frangible connection, and the sleeve which is mounted on the hollow body of the syringe, it is sufficient to elastically deform the ring to release the latter, and with it the protective cap, from the syringe, and this without breaking the frangible connection between the sleeve and the protective cap. Therefore, when using the syringe, the healthcare professional may not notice that the tamper-proof system has been violated.

Other syringes with tamper-proof cap of the known type include the presence of micro-welds between the cap and external portions of the hollow cylindrical body, or of the Luer-lock connector, of the syringe.

Even these known tamper-proof caps, although structurally and functionally simple, do not guarantee to the healthcare professional the total absence of tampering, and therefore the integrity of the product contained in the syringe. In fact, a third party, by using special tools, could remove the micro-welds between the tamper-proof cap and the syringe, access the product contained in the syringe and then make new micro-welds. As a result, the healthcare professional may once again fail to notice that the tamper-proof cap has been violated.

Other prior art syringes provided with tamper-proof cap are disclosed in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

The main object of the present invention is therefore to provide a syringe with Luer-lock connector equipped with tamper-proof cap capable of overcoming the drawbacks mentioned above with reference to syringes with a tamper-proof cap of a known type.

More particularly, the main object of the present invention is to provide a syringe with Luer-lock connector equipped with tamper-proof cap, configured to guarantee the total absence of tampering with the cap and therefore the integrity of the product contained in the syringe.

Still another object of the present invention is to provide a syringe with Luer-lock connector equipped with a tamper-proof cap, which is structurally simple and can therefore be easily assembled on the syringe, without the aid of machine tools and/or welding methods, for example ultrasonic welding.

Last but not least, an object of the present invention is to provide a syringe with Luer-lock connector equipped with a tamper-proof cap, which can be produced in a timely manner and at competitive costs.

These and other objects of the present invention are achieved by a syringe with Luer-lock connector equipped with tamper-proof cap incorporating the features of the appended claims, which form an integral part of the present description.

The invention thus relates to a syringe comprising a hollow cylindrical body, containing a product to be injected and from which a hollow tip equipped with Luer-lock connector extends, and a plunger, sliding inside the hollow cylindrical body.

The syringe also comprises a tamper-proof cap, comprising a closure cap and a tamper-proof insert, in which the closure cap includes a portion for coupling with the Luer-lock connector and a handle portion. An external seat for housing the tamper-proof insert is formed in the handle portion.

The tamper-proof insert comprises at least one longitudinal section, a transverse section and a terminal element, which is connected to a free end of the longitudinal section by a frangible connection, the terminal element being configured to be immovably housed in a corresponding groove formed on an external surface of the Luer-lock connector.

The tamper-proof cap further comprises means for the unmovable coupling between the tamper-proof insert and the closure cap.

A tamper-proof cap is formed thanks to this combination of features, in particular thanks to the unmovable coupling mode between the tamper-proof insert and the closure cap and the Luer-lock connector. In fact, since the closure cap and the tamper-proof insert are immovably coupled therebetween, the tamper-proof insert is no longer separable from the closure cap and forms a single body with it. As a result, when the tamper-proof insert is mounted on the closure cap and on the Luer-lock connector of the syringe, it is impossible to tamper with the cap. The only way to unscrew the cap from the syringe is to break the tamper-proof insert at the frangible connection.

In an embodiment, the unmovable coupling means comprise at least one coupling element, which extends from the transverse section of the tamper-proof insert, towards the inside of the tamper-proof insert, in order to be coupled by interference with a corresponding cavity of the closure cap, which extends, preferably longitudinally, towards the inside of the handle portion of the closure cap.

In an embodiment, at least the at least one unmovable coupling element is wedge-shaped or the corresponding cavity of the closure cap has slightly inclined walls.

In an embodiment, the unmovable coupling means comprise at least one hooking element, which extends from the transverse section of the tamper-proof insert, towards the inside of the tamper-proof insert, in order to be snap-fittingly housed in a corresponding cavity of the closure cap, which extends, preferably longitudinally, towards the inside of the handle portion of the closure cap.

In an embodiment, the hooking element has a terminal tooth configured to be snap-fittingly housed in a corresponding transversely projecting section of the cavity of the closure cap, so as to achieve an unmovable coupling between the tamper-proof insert and the closure cap.

In an embodiment, the tamper-proof insert comprises two longitudinal sections that are connected therebetween by the transverse section and a pair of terminal elements, each connected to a free end of a respective longitudinal section by a frangible connection, the terminal elements being configured to be housed in corresponding grooves formed on the external surface of the Luer-lock connector.

In an embodiment, the at least one unmovable coupling element comprises a pair of unmovable coupling elements, which are suitably spaced therebetween and each immovably housable in a corresponding cavity of the closure cap.

In an embodiment, the tamper-proof insert comprises two pairs of unmovable coupling elements, the unmovable coupling elements of each pair being opposed and suitably spaced therebetween, each pair being immovably housable in a corresponding cavity of the closure cap.

In an embodiment, the unmovable coupling means comprise a layer of glue applied between the tamper-proof insert and the closure cap.

In an embodiment, the unmovable coupling means consist of welding points or continuous welding applied between the tamper-proof insert and the closure cap.

In an embodiment, the frangible connection between the free end of each longitudinal section and the respective terminal element of the tamper-proof insert consists of a narrowing having a smaller section than that of the transverse section and the terminal elements of the tamper-proof insert.

In an embodiment, each groove of the Luer-lock connector has side and bottom walls which are inclined towards the inside of the groove and a chamfered inlet open end, opposite to the bottom wall.

In an embodiment, each terminal element of the tamper-proof insert has tapered edges which, when the terminal elements are inserted into the grooves of the Luer-lock connector, cooperate with the corresponding inclined side and bottom walls of the longitudinal grooves. In this way, the terminal elements of the tamper-proof insert are held within the grooves formed at the Luer-lock connector of the syringe, so that they are prevented from being lifted, either intentionally or unintentionally, in order to separate the tamper-proof insert from the cap, without causing a breakage in the frangible weakening zones.

In an embodiment, an annular surface, preferably normal to the longitudinal axis of the closure cap and which is designed to come into abutment against a corresponding annular surface of the Luer-lock connector, preferably normal to the longitudinal axis of the Luer-lock connector is delimited between the handle portion and the coupling portion of the closure cap.

In an embodiment, the tamper-proof cap further comprises a rubber housed in an axial cylindrical cavity of the closure cap, wherein the rubber has a first surface, a second surface, opposite to the first surface and facing an opening of the axial cavity so as to abut, in use, against a free end of the hollow tip of the syringe, and a side surface.

In an embodiment, at least one, preferably a series of longitudinal grooves is formed at the side surface of the rubber.

In an embodiment, the first surface of the rubber is plane or convex, with convexity facing the hollow tip of the syringe.

In an embodiment, two recesses are further formed in the handle portion, which extend substantially for the entire length of the handle portion and are arranged on opposite sides with respect to the external seat for housing the tamper-proof insert.

In an embodiment, the tamper-proof insert has a different colour from that of the closure cap. This advantageously allows a rapid and immediate identification of the tamper-proof insert, and therefore of the integrity thereof or not, by a user of the syringe.

Further features and advantages of the present invention will be more evident from the following description.

The invention will be described hereinbelow with reference to certain examples provided by way of non-limiting example and illustrated in the accompanying drawings. These drawings illustrate different aspects and embodiments of the present invention and reference numerals illustrating structures, components, materials and/or similar elements in different drawings are indicated by similar reference numerals, where appropriate.

While the invention is susceptible to various modifications and alternative constructions, certain preferred embodiments are shown in the drawings and are described hereinbelow in detail. It must in any case be understood that there is no intention to limit the invention to the specific embodiment illustrated, but, on the contrary, the invention intends covering all the modifications, alternative and equivalent constructions that fall within the scope of the invention as defined in the claims.

The use of "for example", "etc.", "or" indicates non-exclusive alternatives without limitation, unless otherwise indicated. The use of "includes" means "includes, but not limited to" unless otherwise indicated.

With reference to <FIG>, it is therein illustrated a syringe with Luer-lock connector equipped with tamper-proof cap according to a preferred embodiment of the present invention.

The syringe, generally indicated by reference number <NUM>, is preferably a pre-filled syringe and comprises a hollow cylindrical body <NUM>, typically transparent, containing a product to be injected, and a plunger <NUM>, sliding inside the hollow cylindrical body <NUM>.

As shown in <FIG>, a hollow and substantially frusto-conical tip <NUM>, onto which a needle (not shown) is subsequently fitted for the injection of the product present in the cylindrical body <NUM>, extends from the hollow cylindrical body <NUM>. At the tip <NUM> there is a Luer-lock connector <NUM> provided with an internal threading <NUM>. A space S is delimited between the Luer-lock connector <NUM> and the tip <NUM>.

Two longitudinal grooves <NUM>, preferably diametrically opposite therebetween, are also formed on an external surface <NUM> of the Luer-lock connector <NUM>, precisely at one free end of the Luer-lock connector, the function of which will become clearer in the following of this description. Alternatively, and without departing from the scope of the present invention, only one longitudinal groove <NUM> can be provided.

Each groove <NUM> has side 16a and bottom 16b walls, preferably inclined towards the inside of the groove <NUM> to form slots. Each groove <NUM> also has an open end 16c, opposite to the bottom surface 16b, for entering each groove <NUM>. The open end 16c is preferably chamfered.

With reference again to <FIG>, the syringe <NUM> is closed by a tamper-proof cap <NUM>, which comprises a closure cap <NUM> and a tamper-proof insert <NUM>, which can be immovably coupled therebetween.

As shown in detail in <FIG>, the closure cap <NUM> comprises a substantially cylindrical portion <NUM> for coupling with the Luer-lock connector <NUM> of the syringe <NUM> and a handle portion <NUM>, it also being substantially cylindrical.

The coupling portion <NUM> has an external diameter smaller than the external diameter of the handle portion <NUM>, whereby an annular surface <NUM>, preferably normal to the longitudinal axis of the closure cap <NUM>, is delimited between the handle portion <NUM> and the coupling portion <NUM>. When the closure cap <NUM> is fitted onto the syringe <NUM>, the annular surface <NUM> is designed to come into abutment against a corresponding annular surface <NUM> of the Luer-lock connector <NUM>, preferably normal to the longitudinal axis of the Luer-lock connector <NUM>. As will be described in detail below, the presence of the annular surfaces <NUM> and <NUM>, which achieve the mechanical abutment, is particularly advantageous when assembling the tamper-proof cap <NUM> onto the syringe <NUM>.

The coupling portion <NUM> also has an external threading <NUM> for coupling with the internal threading <NUM> of the Luer-lock connector <NUM> of the syringe <NUM>.

The handle portion <NUM> has an external seat <NUM> for housing the tamper-proof insert <NUM>. In particular, the external seat <NUM> is U-shaped and has two longitudinal sections 216a, formed on a side surface of the handle portion <NUM> and preferably opposed therebetween with respect to a plane passing through the longitudinal axis of the closure cap <NUM>, and a transverse section 216b, for the connection between the longitudinal sections 216a, which is formed on an upper surface of the handle portion <NUM>.

At the junction area between each longitudinal section 216a and the transverse section 216b of the external U-shaped seat <NUM>, respective cavities <NUM> are also formed, which are designed to house corresponding elements for the unmovable coupling of the tamper-proof insert <NUM> to the closure cap <NUM>. In particular, each cavity <NUM> extends longitudinally towards the inside of the handle portion <NUM> of the closure cap <NUM> and ends with at least one, preferably two sections 217a, projecting transversely from both parts of the cavity <NUM> and the function of which will become clearer in the following of the present description. Alternatively, each cavity <NUM> is free of the projecting sections 217a and preferably has slightly inclined walls, so as to snap fit a parallelepiped-shaped pin inserted therein.

Alternatively, and without departing from the scope of the present invention, it is possible to provide an external seat <NUM> having a single longitudinal section and a single cavity <NUM> at the junction area between the longitudinal section and the transverse section of the external seat <NUM>.

Two recesses <NUM> are further formed in the side surface of the handle portion <NUM>, which form two flat faces, parallel and symmetrical with respect to the plane passing through the longitudinal axis of the closure cap <NUM>. The recesses <NUM> extend substantially for the entire length of the handle portion <NUM> and are arranged at opposite sides with respect to a longitudinal plane and normal to the longitudinal sections 216a of each external seat <NUM>. The recesses <NUM> are specular to each other with respect to the plane normal to the longitudinal axis of the closure cap <NUM> and have the function of accommodating the fingers of a user to facilitate the operation of unscrewing the tamper-proof cap <NUM> from the syringe <NUM>. As an alternative to the recesses <NUM>, a smooth or faceted external surface can be provided.

As clearly visible in <FIG>, an axial cavity <NUM>, it being also substantially cylindrical, having an opening 219a at the coupling portion <NUM> is formed in the closure cap <NUM>. The axial cylindrical cavity <NUM> also has a side surface <NUM> and an upper surface 220a.

With reference again to <FIG>, the closure cap <NUM> preferably comprises a rubber <NUM>, which is housed in the axial cylindrical cavity <NUM>.

The rubber <NUM> is substantially cylindrical in shape and has a first surface <NUM>, a second surface <NUM>, opposite to the first surface <NUM>, and a side surface <NUM>. The first surface <NUM> faces the opening 219a of the axial cavity <NUM>, so as to abut, in use, against a free end 14a (<FIG>) of the tip <NUM> of the syringe <NUM>, while the second surface <NUM> abuts, in use, against the upper surface 220a of the axial cylindrical cavity <NUM> of the closure cap <NUM>.

The first surface <NUM> and the second surface <NUM> are preferably plane, while at least one, preferably a series of longitudinal grooves <NUM> is formed at the side surface <NUM>, which allow the user to deform the rubber <NUM> to facilitate, advantageously, the insertion thereof into the axial cylindrical cavity <NUM> of the closure cap, during assembly of the tamper-proof cap <NUM>. The longitudinal grooves <NUM> also advantageously favour the leakage of air during the insertion of the rubber <NUM> into the axial cylindrical cavity <NUM>, during the assembly of the tamper-proof cap <NUM>, so that no air remains trapped between the upper surface 220a of the axial cylindrical cavity <NUM> and the second surface <NUM> of the rubber <NUM>.

The first surface <NUM> of the rubber <NUM> designed to abut, in use, against the tip <NUM> of the syringe <NUM> may be convex, with convexity facing the tip <NUM>. In this case, as the tamper-proof cap <NUM> is screwed onto the syringe <NUM>, the first convex surface <NUM> of the rubber <NUM> flattens, thus abutting against the tip <NUM> of the syringe <NUM>, air-tightly closing the opening thereof.

With reference in particular to <FIG> and <FIG>, the tamper-proof insert <NUM> comprises a main body <NUM>, whose shape is complementary to that of the external seat <NUM> of the handle portion <NUM> and configured to be immovably coupled with the closure cap <NUM>, so as to form a single body with it.

The tamper-proof insert may be immovably housed, for example glued or welded, for example by ultrasonic welding, inside the external seat <NUM>, so as to form a single body with the closure cap <NUM>. By way of example, the unmovable coupling between the tamper-proof insert <NUM> and the closure cap <NUM> is achieved by applying a layer of glue between the external seat <NUM> of the handle portion <NUM> of the closure cap <NUM> and a respective longitudinal section <NUM> of the tamper-proof insert <NUM> or between one or more of the unmovable coupling elements <NUM> and the corresponding housing cavity <NUM>.

The tamper-proof insert <NUM> further comprises at least one terminal element, preferably a pair of terminal elements <NUM>, each configured to engage immovably with a corresponding longitudinal groove <NUM> of the Luer-lock connector <NUM>. Preferably, each terminal element <NUM> has tapered edges 222a and 222b, which, when the terminal element is inserted into the corresponding longitudinal groove, cooperate with corresponding inclined side 16a and bottom 16b walls of the longitudinal groove, so as to prevent the terminal element from being lifted without causing it to break, which would signal to the user of the syringe <NUM> that the tamper-proof cap <NUM> has been tampered with.

Similar to the external seat <NUM> of the handle portion <NUM> of the closure cap <NUM>, the main body <NUM> of the tamper-proof insert <NUM> comprises at least one, preferably two longitudinal sections <NUM> and a transverse section <NUM>, for the connection between the longitudinal sections <NUM>. Each terminal element of the pair of terminal elements <NUM> extends from a free end of a corresponding longitudinal section <NUM> and is connected thereto by a frangible connection <NUM>, preferably consisting of a narrowing having a smaller section than that of the longitudinal section <NUM> and the terminal element <NUM>.

From a central area of the transverse section <NUM> of the tamper-proof insert <NUM> there extends, towards the inside of the tamper-proof insert <NUM> and in proximity to a respective longitudinal section <NUM> of the tamper-proof insert <NUM>, at least one means for the unmovable coupling of the tamper-proof element <NUM> to the closure cap <NUM>, having the shape of a hooking element <NUM>, preferably of two hooking elements <NUM>, even more preferably of two pairs of hooking elements <NUM>. The hooking elements <NUM> of each pair extend, opposed and suitably spaced therebetween, transversely to the respective longitudinal section <NUM> of the tamper-proof insert <NUM>.

Each hooking element <NUM> is designed to be housed in a corresponding cavity <NUM> of the closure cap <NUM> and has a terminal tooth 226a configured to be snap-fittingly housed in a corresponding transversely projecting section 217a of the cavity <NUM>, so as to achieve an unmovable coupling between the tamper-proof insert <NUM> and the closure cap <NUM>.

Alternatively, the unmovable coupling means consist of one or more unmovable coupling elements, each configured to be coupled by interference with the corresponding cavity <NUM> of the closure cap. For this purpose, the unmovable coupling element is wedge-shaped or the respective cavity <NUM> of the closure cap <NUM> has slightly inclined walls, so as to snap fit a parallelepiped-shaped pin inserted therein.

When the tamper-proof insert <NUM> is immovably coupled to the closure cap <NUM>, the hooking elements <NUM> are internal to the tamper-proof cap <NUM> and therefore not accessible from the outside. This makes it advantageously impossible to separate the tamper-proof insert <NUM> from the closure cap <NUM>, for example as a result of elastic deformation of the hooking elements <NUM>, for tampering purposes.

Furthermore, since the main body <NUM> of the tamper-proof insert <NUM> is complementary in shape to that of the external seat <NUM> of the handle portion <NUM> of the closure cap <NUM>, the tamper-proof insert <NUM>, when immovably coupled to the closure cap <NUM>, forms a single outline with the latter, so that the tamper-proof cap <NUM> does not have, in the handle portion <NUM>, unsightly and annoying projecting parts. As well as being advantageous in terms of aesthetics and functionality, this aspect allows, when filling the syringe <NUM> with a drug product, to use the same supports used for syringes that use caps without tamper-proof inserts and oversized tamper-proof systems in general.

Preferably, the colour of the tamper-proof insert <NUM> is different from that of the closure cap <NUM>, for example red in colour. This allows a rapid and immediate identification of the tamper-proof insert, and therefore of the integrity thereof or not, by a user of the syringe.

The closure cap <NUM> and the tamper-proof insert <NUM> are preferably made of a non-flexible plastic material, for example compact polycarbonate (Makrolon®), cyclic-olefin polymer (COP), or cyclic-olefin copolymer (COC).

With reference to <FIG> and <FIG>, the method for the manual and automatic assembly of the tamper-proof cap <NUM> onto the syringe <NUM> is now described.

In the manual assembly phase, the closure cap <NUM> is first screwed onto the Luer-lock connector <NUM> of the syringe <NUM>, by coupling the external threading <NUM> of the coupling portion <NUM> with the internal threading <NUM> of the Luer-lock connector <NUM>, until each longitudinal section 216a of the external seat <NUM> of the coupling portion <NUM> is aligned with the corresponding groove <NUM> of the Luer-lock connector <NUM>.

Otherwise, in the case of automatic assembly, for example by means of an automatic screwing system, the closure cap <NUM> is screwed onto the Luer-lock connector <NUM> of the syringe <NUM>, by coupling the external threading <NUM> of the coupling portion <NUM> with the internal threading <NUM> of the Luer-lock connector <NUM>, until the annular surface <NUM> of the coupling portion <NUM> is brought into abutment against the corresponding annular surface <NUM> of the Luer-lock connector. At this point, the automatic screwing system detects a sudden increase in the torque required for screwing, and this indicates that the so-called mechanical "zero" has been reached, from which the mechanical screwing system moves on unscrewing the closure cap <NUM> by a predetermined angle, so as to bring each longitudinal section 216a of the external seat <NUM> of the coupling portion <NUM> into alignment with the corresponding groove <NUM> of the Luer-lock connector <NUM>, while ensuring that the syringe <NUM> is hermetically closed.

If the rubber <NUM> is present, before screwing the closure cap <NUM> onto the Luer-lock connector <NUM> of the syringe <NUM>, the rubber <NUM> is inserted inside the axial cylindrical cavity <NUM> of the closure cap <NUM> until the second surface <NUM> of the rubber <NUM> is brought into abutment with the upper surface 220a of the axial cylindrical cavity <NUM>. In such a case, at the end of screwing the closure cap <NUM> onto the Luer-lock connector <NUM>, the first surface <NUM> of the rubber <NUM> is in abutment against the free end 14a of the tip <NUM> of the syringe <NUM>.

Once the closure cap <NUM> has been screwed onto the Luer-lock connector <NUM>, with each longitudinal section 216a of the external seat <NUM> of the coupling portion <NUM> in alignment with the corresponding groove <NUM> of the Luer-lock connector <NUM>, the tamper-proof insert <NUM> is mounted on the closure cap <NUM>.

For this purpose, and as shown in <FIG>, the tamper-proof insert <NUM> is fitted onto the external seat <NUM> of the closure cap <NUM> and slid inside the external seat <NUM>, so as to establish an unmovable coupling between the tamper-proof insert <NUM> and the closure cap <NUM>.

In particular, if unmovable coupling elements are provided, these are housed, either by interference or by snap-fit, in the respective cavity <NUM> of the closure cap.

With particular reference to the hooking elements <NUM>, when the tamper-proof insert <NUM> is fitted onto the closure cap <NUM>, the terminal hooking teeth 226a of the hooking elements <NUM> of the tamper-proof insert <NUM> are snap-fittingly housed, by elastic deformation, in the corresponding transversely projecting sections 217a of the cavities <NUM> present inside the closure cap <NUM> and the terminal elements <NUM> of the tamper-proof insert <NUM> are housed, also immovably, inside the longitudinal grooves <NUM> of the Luer-lock connector <NUM>.

Precise insertion, and subsequent sliding without breakage, of the terminal elements <NUM> into the longitudinal grooves <NUM> is ensured by the chamfered open end 16c of the longitudinal grooves <NUM> and by the cooperation of the tapered edges 222a and 222b of the terminal elements <NUM> with the corresponding inclined side 16a and bottom 16b walls and of the longitudinal grooves <NUM>.

<FIG> illustrates the tamper-proof cap <NUM> in its operating, tight-closure and tamper-proof position on the Luer-lock connector <NUM> of the syringe <NUM>.

It is assumed, now, that one wishes to decouple the tamper-proof cap <NUM> from the syringe <NUM>. The user, typically a healthcare professional who has to inject the drug product contained in the hollow cylindrical body <NUM> of the syringe <NUM> into a patient's body, proceeds to unscrew the tamper-proof cap <NUM>.

Since the terminal elements <NUM> of the tamper-proof insert <NUM> are immovably housed within the longitudinal grooves <NUM> of the Luer-lock connector <NUM>, the rotation of the tamper-proof cap <NUM> with respect to the Luer-lock connector <NUM> causes the frangible connections <NUM> between the terminal elements <NUM>, fixed, and the corresponding longitudinal sections <NUM>, rotatingly movable, of the tamper-proof insert <NUM> to break.

The breakage of the frangible connections <NUM> therefore causes the assembly closure cap <NUM> and tamper-proof insert <NUM> - deprived of its terminal elements <NUM> - to separate from the Luer-lock connector <NUM> and the syringe <NUM> to open.

From the foregoing, it is understood that the only way to separate the tamper-proof insert <NUM> from the closure cap <NUM> is to break the frangible connections <NUM> of the tamper-proof insert <NUM>, so that, if the tamper-proof cap <NUM> had been tampered with, the user of the syringe <NUM> would immediately notice that it had been broken, thus immediately detecting the evidence of tampering.

It should also be noted that it is not possible for an external subject to tamper with the tamper-proof cap <NUM>, i.e. to decouple the tamper-proof cap <NUM> from the Luer-lock connector <NUM>, without breaking the tamper-proof insert <NUM> at the appropriate frangible connections <NUM>. In fact, the elements <NUM> for the unmovable coupling between the tamper-proof insert <NUM> and the closure cap <NUM> are internal to the tamper-proof cap <NUM> and cannot be accessed from the outside and are therefore impossible to violate.

From the description made, the characteristics of the syringe with Luer-lock connector equipped with tamper-proof cap of the present invention are clear, as are the advantages thereof.

Claim 1:
A syringe (<NUM>) comprising:
- a hollow cylindrical body (<NUM>), containing a product to be injected and from which a hollow tip (<NUM>) equipped with a Luer-lock connector (<NUM>) extends, and a plunger (<NUM>), sliding inside the hollow cylindrical body (<NUM>); and
- a tamper-proof cap (<NUM>) comprising a closure cap (<NUM>) and a tamper-proof insert (<NUM>), wherein the closure cap (<NUM>) includes a portion (<NUM>) for coupling with the Luer-lock connector (<NUM>) and a handle portion (<NUM>), in which an external seat (<NUM>) for housing the tamper-proof insert (<NUM>) is formed, and
wherein the tamper-proof insert (<NUM>) comprises at least one longitudinal section (<NUM>) a transverse section (<NUM>) and means (<NUM>) for the unmovable coupling of the tamper-proof insert (<NUM>) and the closure cap (<NUM>);
characterized in that the tamper-proof insert (<NUM>) comprises a terminal element (<NUM>), which is connected to a free end of the longitudinal section (<NUM>) by a frangible connection (<NUM>), the terminal element (<NUM>) being configured to be immovably housed in a corresponding groove (<NUM>) formed on an external surface (<NUM>) of the Luer-lock connector (<NUM>),
and in that the means (<NUM>) for the unmovable coupling of the tamper-proof insert (<NUM>) and the closure cap (<NUM>) comprises at least one element (<NUM>) extending from the transverse section (<NUM>) of the tamper-proof insert (<NUM>), towards the inside of the tamper-proof insert (<NUM>), in order to be coupled by interference with a corresponding cavity (<NUM>) of the closure cap (<NUM>), which extends towards the inside of the handle portion (<NUM>) of the closure cap (<NUM>).