MXPA97006667A - Low friction coating for cartu seal hood - Google Patents

Abstract

An improvement to a coupling system for transferring a liquid medicament from a cartridge (10) to a needle unit (60) is described in which the improvements comprise a low friction coating deposited on the metal seal hood (30) ( 3

Description

LOW FRICTION COATING FOR CARTRIDGE SEAL HOOD. DESCRIPTION OF THE INVENTION This invention relates to a low friction coating for a coupling system for transferring liquid medicaments from one flow conduit to another, and more particularly to a low friction coating for a cartridge seal hood used in conjunction with disposable units containing liquid medication and cartridge needle. Disposable needle and cartridge units for liquid medicament are well known in the art and of wide commercial use. Such cartridges conventionally have a cartridge barrel, formed of glass or plastic having a distal end and a near end. The near end of the cartridge is closed with a slidable diver, while the distal end has a neck part ending in a closed opening by a diaphragm or septum attached to the cartridge by a tight metal collar, usually an aluminum collar, The neck portion of the distal end is adapted to receive and attach a needle-plug-needle-needle assembly. The needle plug portion fits into the diaphragm in a shape relationship. When the plug or mass is fitted into the cartridge, the proximal end of the needle cannula pierces the diaphragm thus providing communication between the needle cannula and the liquid medication contained in the barrel of the cartridge. Such a needle-mass shield assembly or needle-needle plug is shown for example in US Pat. No. 5,358,491. One of the major problems in providing liquid pharmaceutical products for injection to patients is the generation and presence of matter. strange particles that can contaminate the product, in order to eliminate the macroscopic and microscopic particles, have taken elaborate measures to remove them, such as filtration of the product and special washing and drying of the component of the closure system. These steps help the products comply with the requirements and guidelines of the pharmaceutical industry, such as the content guidelines when the products reach the point of use. however, at the point of use new foreign material is frequently generated by the user when the septum or lid is pierced by the needle of the injectable set, during such penetration a combination of elastic and plastic deformation of the area sought increases the contact surface of the septum with the needle when it is pressed into the cap. Typically, untreated elastomer covers offer high resistance against the outer surface of the needle when the needle is inserted into the penetration area. More frequently when fragments of the lid are produced, they are the result of the elastoic part of the lid that is torn on its upper surface as it adapts to the shape of the needle, then the fragments or enters the cannula of the needle or inside the cartridge when the needle pushes the fragments during penetration. The most common solution to the problem of 1 particulate material has been the application of silicone lubricant to the cap to reduce the frictional thrust between the cap and the needle. While silicone reduces the generation of particulate material, it also increases the risk of contamination of the product by its own composition. Another way sought in the prior art to reduce the tendency of the plug to generate particulate material is to cover the elastomeric core of the lid with a thermoplastic film on the side that contacts the fluid. Another attempt was proposed in US Patent No. 5, 219, 083 to eliminate or greatly reduce generation from the cap during needle penetration, by applying an abrasion-resistant, inert coating to the near surface of the cap this is a the surface of the lid that has no contact with the pharmaceutical liquid contained in the cartridge. Although these attempts greatly reduce the production and presence of particulate material caused by the cap during the penetration of the needle, we have observed the presence of original particles of crushed metal collar that keeps the lid in place on the cartridge. Such particles are produced during the process of making the collar and crushing it. similarly to the result of the production of particulate material originating from the cap, the original particulate material of the collar can enter the needle cannula causing its packing or the application to the patient of a pharmaceutical liquid contaminated with metallic particles. One of the objects of the present invention is to eliminate or at least greatly reduce the tendency to that fact. Another object of the present invention relates to the reduction of the activating force needed to activate the needle-mass needle-needle assembly when the content of the cartridge is to be injected into the patient. Conventionally, the cartridge, which contains the liquid medicament, is packaged separately from the assembly or assembly needle = needle hub. Before the injection the assembly is fitted on the cartridge, the proximal end of the needle cannula penetrates the cap, and the needle guard is removed to have the device ready for injection. During this process, it is desirable that the fitting process be easy, that it does not require excessive force, as well as that the injection be completed and the needle protection assembly - the stem - the needle - be removed from the cartridge, the necessary force being not excessive for the average user, we have found that both the lace and the withdrawal step tend to be uncomfortable for some users. As a result of intensive studies aimed at solving this problem, as well as to solve the problem of the presence of particulate material originating from the metal hood that stops the lid in place, we find that a coating during the manufacture of the metal hood or after the hood is tightened on the cap and the cartridge, it greatly reduces or completely eliminates the need to apply excessive force by the user to activate and / or deactivate the cartridge containing the liquid medicament. In accordance with the present invention a low friction coating is provided for a coupling system which serves to transfer medicaments from one flow conduit to another, and more particularly, to a low friction coating for a cartridge sealing hood used in conjunction with cartridge needle units containing liquid medicament to eliminate or at least greatly reduce the presence of particulate materials originating from the coupling system and to reduce the activation and deactivation force of the device. in particular, the invention provides an improvement in a needle-cartridge assembly wherein the cartridge comprises: a) a cartridge barrel having a distal end and a proximal end; an axially slidable diver and reciprocally in the barrel of the cartridge; a cap of an elastic material that seals the distal end of the cartridge barrel; a cartridge sealing hood having an opening located centrally to allow a needle to penetrate the lid, that cartridge sealing hood securely stopping the lid in place; b) a needle assembly unit comprising: a plug that axially stops a needle, the needle has a distal end and a near end, the plug comprises a sleeve constructed to engage at the distal end of the cartridge while the near end of the needle penetrates the lid in the cartridge; and c) a sheath covering the distal end of the needle constructed to fit over the plug to serve as the user's protection against the needle; wherein the improvement comprises: a coating of a low friction material that covers the sealing hood of the cartridge to prevent the particulate material originating from the cartridge seal from entering the needle and to reduce the frictional force necessary to activate and deactivate the cartridge. cartridge.

The coating of the metal seal hood of the cartridge may be made during the manufacture of the hood or after the hood has been placed on the cartridge. Such a coating may be: a polyolefin such as polypropylene and polymethylpentene; a polyvinyl such as polystyrene, vinyl acetate (PVA), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), a copolymer of polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC), a polyvinyl chloride copolymer ( PVC) and polyvinylidene chloride (PVDC), polyvinyl fluoride, and polyvinylidene fluoride; an ether such as polymethylene oxide, polyphenylene oxide and polyphenylene sulfone; an ester such as polyethylene terephthalate (PET) polycarbonate and copolyester, an ester such as polycaprolactam (nylon 6); adipamide polyhexamethylene (nylon 66), and polyundecanoamide (nylon 11). We have found that polytetrafluoroethylene (TEFLON) provides one of the best low friction coating materials. The thickness of the coating will be in the range of about 0.002 to 1.0 mm and preferably in the range of about 0.2 to 0.5 mm. the coating may be applied or bonded to the material of the metal layer in any suitable manner known to the artisan, such as, but not limited to, the use of adhesives, solvents, applications with dew, radiated waves, infrared, microwaves, ultrasonics and heat . If the coating of the sealing hood is made after tightening or crushing, the coating can also cover the central portion of the cap that is exposed by the opening in the sealing hood. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate one embodiment of the present invention, wherein: Figure 1 is a plan view of a needle assembly unit showing a plug axially stopping the needle; Figure 2 is a plan view of a cartridge; Figure 3 is a plan view of a sheath for covering the needle shown in Figure 1; Figure 4 is a plan view of a diver for use in the cartridge shown in Figure 2; Figure 5 is a plan view of a fully assembled cartridge, diver, plug-needle assembly without the sheath; Figure 6 is a fragmentary longitudinal cross-section of the distal end of the cartridge having the cap in place, the cap sealing tight and a portion of the plug and needle before the needle pierces the cap or septum; and Figure 7 is a fragmentary, enlarged longitudinal cross-section of the distal end of the cartridge having the cap in place, the cap sealing tight and a portion of the plug and needle after the needle has pierced the cap or septum. This invention is useful in conjunction with a wide variety of cartridges activatable by a nestable needle unit. The invention will now be described with reference to the drawings that illustrate a preferred embodiment of the present invention. Shown in Figure 1, the cartridge 10 comprising a cartridge barrel 20, formed of glass and plastic having a distal end 26 and a near end 40. The distal end 26 has a neck part 28 that terminates in an opening (not shown), closed by a diaphragm seal or hood 30 and a septum or diaphragm or cap 36. the sealing hood 30 contains an annular groove 32 for receiving a lace-like hypodermic needle 60 which is shown in FIG. Figure 1. The hypodermic needle assembly 60 comprises a lace portion 62 that is to be coupled to the sealing hood 30 in a shape relationship, and a conical portion 64 that is to receive and engage with the proximal end 74 of the sleeve or sheath 70. When the hypodermic needle assembly 60 is engaged in the cartridge, the proximal end of the needle 66 pierces the septum 36, producing a communication between the needle and the liquid medicament 24 contained in the barrel of the cartridge 20. proximal end 40 of cartridge 10 is open to receive a diver or piston 50, shown in the Figure, having a front liquid interface surface 52 and a threaded portion 56 extending rearwardly to interconnect with a piston rod (not shown) when the cartridge is ready for use. Figure 6 shows an enlarged fragmentary longitudinal section through the distal end of the cartridge barrel 20, which has the lid or septum 36 covering the barrel's distal opening, the tight sealing hood 30 and the fitting portion 62 of the barrel assembly. Hypodermic needle. As shown in this stage of the process, the proximal end of the needle 66 has not pierced the septum or lid 36. Figure 7 shows the same parts and the same special configuration, except that the proximal end of the needle 66 has already drilled the lid 36. As shown the tight seal hood 30 includes the opening 38 in its central portion to expose the cap or septum that lies below 36 and allow perforation thereof by the proximal end of the needle 66. the hood 30 The seal seal is covered with a low friction polymeric coating 80. The coating can cover the outer surface of the seal hood or can cover both its outer and inner surfaces. When the coating is applied after the seal hood has been pressed or bent over the cartridge, the coating can also cover the exposed central surface of the cap or septum. Referring now to the construction materials, those materials are obtainable from commercial sources. The lid can be made of rubbery, deformable materials capable of automatically resealing after being perforated. The preferred materials possess a Shore A hardness of about 50 to 70. The sealing hood which stops the lid in place after it has been tightened, is made of any suitable metallic material, preferably aluminum. The needle unit, except the needle itself which is made of stainless steel, is made of plastic. Suitable plastics include polypropylene, polystyrene, nylons, acetals, polyethylene and polyester. Referring now to the use of the device, the health professional or medical assistant receives the device in a form where the cartridge is pre-filled with the liquid medication and is sealed at both ends; the distant end is sealed by the septum and the sealing hood, while the proximal end is closed by the diver, the diver's bar is not attached to the diver and neither is the needle fitted to the distal end of the cartridge. device to use it, the needle-cartridge unit is activated causing the proximal end of the needle to pierce the septum and the cartridge moves forward to the socket to reach the socket position. The fitting step is convenient and easy since the smooth coating surface of the sealing hood exerts little frictional force on the plug of the needle unit. The diver or piston rod is screwed onto the diver's pole, finally the sheath covering the exposed part of the needle is removed. Subsequently, the distal end of the needle is inserted in the place where the injection will be applied and the liquid medication is delivered to the patient by applying a force directed axially to the diver's bar. the activation force of the cartridge was determined by sealing hoods covered with TEFLON and not tightly packed over cartridges. An Instron 4502 device was used to determine the maximum load expressed in pounds to activate the needle inside the cartridge, using 40 samples from each of the covered and uncovered samples. The average forces and standard deviations were as follows: Samples Average Standard deviation covered Teflon 5.585 0.800 not covered 10.561 1.534 The present invention has been described in relation to the preferred embodiment shown in the drawings, but it is to be noted, that various changes and modifications are apparent to those skilled in the art. R E I V I N D I C A C I O N E S.

Claims (7)

1. - A cartridge assembly improved needle characterized in that it comprises: (a) a cartridge (b) a needle assembly unit and a sheath, the cartridge consisting of: a cartridge barrel having a distal end and a proximal end; an axially slidable diver and reciprocally in the barrel of the cartridge; a cap of an elastic material that seals the distal end of the cartridge barrel; a cartridge sealing hood having an opening located centrally to allow a needle to penetrate the lid, that cartridge sealing hood securely stopping the lid in place; The needle assembly unit consists of: a plug that axially stops a needle, the needle has a distal end and a near end, the plug comprises a sleeve constructed to engage at the distal end of the cartridge while the near end of the needle penetrates the cap on the cartridge; and a sheath covering the far end of the needle constructed to fit over the plug to serve as a user protection against the needle; the improvement consisting of: a coating of a low friction material that covers the sealing hood of the cartridge to prevent the particulate material originating from the cartridge seal from entering the needle and to reduce the frictional force necessary to activate and deactivate the cartridge .

2. The cartridge-needle assembly according to claim 1, characterized in that the coating is made of polytetrafluoroethylene.

3. The cartridge-needle assembly according to claim 1, characterized in that the coating covers the hood of the cartridge seal both on its outer and inner surface.

4. The cartridge-needle assembly according to claim 1, characterized in that the cover also covers the central portion of the lid exposed by the opening in that cartridge seal hood.

5. The cartridge-needle assembly according to claim 1, characterized in that the coating of the seal hood of the cartridge is made before tightening the seal hood on the cartridge.

6. The cartridge-needle assembly according to claim 1, characterized in that the coating of the seal hood of the cartridge is made after tightening the seal hood on the cartridge.

7. The cartridge-needle assembly according to claim 1, characterized in that the coating is carried out by the use of spray application, radio waves, infrared waves, microwaves, ultrasound or heat.