US20240042165A1 - One-Piece Molded Catheter and Method of Manufacture - Google Patents

Abstract

A one-piece catheter (30) and manufacturing method therefor are disclosed. The catheter (30) includes a catheter tube (33) and an adapter (31). The catheter catheter tube (33) includes a tip (331) at one end and an end portion (332) at another other end. The adapter (31) can be configured for receiving a septum (402). The adapter (31) includes a narrow opening. The end portion (332) of the catheter tube (33) is connected to the adapter (31) at the narrow opening for fluid communication between the catheter tube (33) and the adapter (31). The catheter tube (33) and adapter (31) are formed as a one-piece element that is preferably injection molded in a single-shot process. Additional elements, such as one or more retention tabs (313) for attaching to a base can be formed on the catheter (30). The one-piece catheter (30) can be made by a single-shot injection molding process. Additional structures, such as a base can be attached to the catheter (30) by a second-shot injection molding process.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This application is a divisional application of U.S. patent application Ser. No. 16/229,190, filed Dec. 21, 2018, which is a divisional application of U.S. patent application Ser. No. 13/984,024, filed Nov. 22, 2013, now U.S. Pat. No. 10,195,393, issued Feb. 5, 2019, which is based on PCT Application No. PCT/US12/00077, filed Feb. 8, 2012, which claims the benefit of U.S. Provisional Application Ser. No. 61/441,258, filed Feb. 9, 2011, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
• The present invention relates to medical catheters and methods of manufacture thereof that minimize the number of components without compromising the functionality of the catheters.
BACKGROUND OF THE INVENTION
• Catheters are widely used in the medical applications. Peripheral or intravenous catheters and infusion set catheters are two frequently used types of catheters. Peripheral or intravenous (IV) catheters infuse medication or other fluids directly into blood vessels. Infusion set catheters are integral parts of infusion sets that deliver medication, such as insulin, into the skin for absorption by the user.
• FIG.1 illustrates a conventional infusion set10 for use with an infusion set catheter to deliver insulin therapy. Theinfusion set10 comprises an extension set, abase19 and acatheter14 attached to thebase19. The extension set comprises ahub12,connector18, fluid line tube set16 connecting thehub12 and theconnector18, and a pump (not shown) connected to theconnector18, such that insulin from the pump is delivered through thecatheter14. An insertion device inserts or attaches the catheter to a user. The infusion set and insertion device can also be combined into one unit.
• Another type of insulin infusion device is a patch pump. Unlike a conventional infusion pump, a patch pump is an integrated device that combines most or all of the fluid components in a single housing which is adhesively attached to an infusion site, and does not require the use of a separate infusion (tubing) set. A patch pump adheres to the skin, contains insulin (or other medication), and delivers the drug over a period of time, usually via an integrated subcutaneous catheter. Patch pump and infusion sets need to be reapplied on a frequent basis, such as every three days, as complications may otherwise occur.
• Catheters used in infusion sets and patch pumps are similar in construction to peripheral or IV catheters, with the infusion set catheters generally being smaller in size.
• A conventional peripheral or IV catheter is illustrated inFIG.2. Theperipheral catheter14′ is generally made of a polymer, such as Teflon®. Thecatheter tube144 is conventionally connected to a rigid metal orplastic wedge143 which is a funnel-shaped device that attaches the catheter to an adapter orhub142 of the catheter. A neck portion of thewedge143 is inserted into an end portion of thecatheter tube144 and the catheter is deformed to frictionally wedge itself into thecatheter adapter142. Thecatheter14′ includes an opendistal tip145.
• In such construction, transmission of impact or vibration forces can damage the catheter at the point of impact as well as at its connection to the wedge, resulting in a weakened connection and/or leaks at the connection. The weakened connection between the catheter and the wedge may also cause the catheter to break off from the wedge during use.
• A complete IVcatheter assembly10′ is illustrated inFIG.3. This device is available as the BD Nexiva™ Closed IV Catheter System from Becton, Dickinson and Company (BD). The indwelling catheter portion is made of BD's Vialon™ biomaterial that reduces mechanical phlebitis (caused by irritation of the venous endothelium by the catheter) and infiltration (which occurs when an IV fluid or medication accidentally enters the surrounding tissue rather than the blood vessel), maximizes dwell time, provides kink resistance (resistance of the catheter to be subject to becoming snagged, knotted or sharply bent to form a kink which impedes or blocks fluid flow) and recovery from kinks, and softens in the vessel.
• Conventional infusion set and/or patch pump catheters, as well as peripheral or intravenous catheters, are susceptible to damage with normal wear, such as kinking. Conventional infusion set catheters are also sometimes fragile due to their construction and material, and are susceptible to damage due to excessive bounce or vibration in the insertion mechanization of the catheter, via an introducer needle, which may result in excessive force being transmitted to the catheters.
SUMMARY OF THE INVENTION
• An object of the present invention is to provide a catheter configured and arranged to optimize column strength for catheter insertion, flexibility for user comfort, and tensile strength for durability, insertion and removal, while minimizing the number of components.
• These and other objects are substantially achieved by providing a catheter whose construction is simplified by combining conventional components into a molded, one-piece unit that combines the functions of the adapter, wedge and catheter tubing, and that can increase overall strength of the structure at key points to prevent leakage of medication through the catheter.
BRIEF DESCRIPTION OF THE DRAWINGS
• The various objects, advantages and novel features of the exemplary embodiments of the present invention will be more readily appreciated from the following detailed description when read in conjunction with the appended drawings, in which:
• FIG.1 is a perspective view of a conventional infusion set;
• FIG.2 is an enlarged cross-sectional view of an end portion of a conventional peripheral or intravenous catheter;
• FIG.3 is a perspective view of a complete peripheral or intravenous catheter assembly;
• FIG.4 is an enlarged cross-sectional view of an exemplary one-piece catheter that includes a base structure in accordance with an embodiment of the present invention;
• FIG.5 is an enlarged cross-sectional view of an exemplary one-piece catheter that includes a base structure in accordance with an embodiment of the present invention;
• FIG.6 is an enlarged cross-sectional view of an infusion set which includes an exemplary one-piece catheter in accordance with an embodiment of the present invention;
• FIG.7 is an enlarged cross-sectional view of an infusion set with an exemplary one-piece catheter in accordance with an embodiment of the present invention;
• FIG.8A is a perspective view of an infusion set;
• FIG.8B is a cross-sectional view of the infusion set ofFIG.8A;
• FIG.9A is an enlarged cross-sectional view of an introducer device primed to insert an exemplary one-piece catheter in accordance with an embodiment of the present invention; and
• FIG.9B is an enlarged cross-sectional view of the insulin device ofFIG.9A; and
• FIG.10 is a cross-sectional view of the introducer device ofFIGS.9A and9B after the needle base has fired.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
• In exemplary embodiments of the present invention, as illustrated inFIGS.4-6, the adapter and catheter are molded in a single unit, eliminating the need for the manufacture and assembly of separate components that include the adapter, catheter tubing, wedge, as well as various tipping operations such as flaring, swaging, cutting and RF tipping operations. In addition, more complex geometries may be molded into the catheter adapter, such as retention tabs for locking the catheter to a base, as illustrated inFIGS.5 and6, as well as one or more side ports for communicating with the fluid connector of an infusion set.
• FIG.4 illustrates one embodiment of the present invention that improves the manufacturing process for a catheter. In theexemplary catheter20 illustrated inFIG.4, thecatheter tube22 is molded together with theadapter21, preferably in a single-shot injection molding process, in which a polymer material is heated to a desired temperature before being injection molded. Such single-shot injection molding process can also be used to make an IV catheter, similar to that which is illustrated inFIG.2. As illustrated inFIG.4, theadapter21 includes a lead-inportion211 that is illustrated as having a funnel shape. The cross-sectional view illustrated inFIG.4 further illustrates that at the apex212 of theadapter21, theend portion222 of thecatheter tube22 is connected (fused together) to theadapter21, such that thecatheter20 is a single piece. At the opposite end of thecatheter tube22, away from theend portion222, is the opendistal tip221 of thecatheter20, through which liquid medication is administered to the patient.
• With reference toFIG.4, the embodiment illustrated in the drawing can be molded with a single-shot injection process, by using a molding process wherein pressure is built up and then released quickly. For the embodiment illustrated inFIG.4, it is preferable to gate in two locations, symmetrically positioned in the adapter area, in order to equalize the pressure on both sides of the core pin, and thus reducing bending of the core pin.
• The cross-sectional view inFIG.5 illustrates another exemplary embodiment of the present invention, adapted for use in an infusion set. Thecatheter30 illustrated inFIG.5 includes anadapter31 sized and configured for receiving a septum (not shown) in the cylindricalmain cavity315 thereof. In addition, theadapter31 includes radially extendingretention tabs313 that are configured for attaching to and or being guided to a base (seeFIGS.9A and10). At the lower portion of theadapter31, a funnel-shaped lead-inportion311 is formed that connects to theend portion332 of thecatheter tubing33. Thecatheter tube33 is shortened in length, as compared with that of the embodiment illustrated inFIG.4. A fluid pathway extends from the opendistal tip331 of thecatheter tube33 through the lead-inportion311. The apex312 of the lead-inportion311 is the site of connection to theend portion332 of thecatheter tube33. As in the embodiment ofFIG.4, theexemplary catheter30 illustrated inFIG.5 is a one-piece design that is preferably molded in a single shot.
• As illustrated inFIGS.9A and10, aseptum402 is received in theadapter31 of thecatheter30. Theretention tabs313 are slotted between theguides601,601′ of thebase600,600′, such that after theintroducer500,500′ has fired to insert theintroducer needle502,502′ with thecatheter30 into a user, theretention tabs313 are secured to thebase600,600′ by theguides601,601′.
• There are several advantages to the one-piece catheter design of the present invention. The one-piece catheter design does away with the need for a wedge that is required in a conventional catheter (as illustrated inFIG.1) for attachment to a catheter base. Such wedge is usually made of a metal or other hardened material, requiring the use of additional materials and processes for the construction of a conventional catheter.
• In contrast, in an exemplary embodiment of the present invention, the one-piece catheter20,30 can use only one material, such as a polymer, reducing the cost of production. In addition, since the exemplary embodiment of the present invention is a one-piece design, it does away with the multiple components of a conventional catheter design.
• FIG.6 illustrates an enlarged cross-sectional view of an infusion set with an exemplary one-piece catheter similar to that ofFIG.5. In the embodiment illustrated inFIG.6, thecatheter40 includes acatheter tube43 and anadapter41. Thecatheter40 is attached to abase45. Thecatheter40 andbase45 can, if desired, be molded together to form a single unit catheter-base assembly via a single-shot molding process. The catheter-base assembly can also be formed by a two-shot molding process in which the first-shot molding process, using a heated polymer made of a material appropriate for extended indwelling in a user, forms thecatheter40. Thereafter, a second molding process, using a heated polymer that may be the same or different from that used in the first-shot, forms and attaches the base45 to thecatheter40. Alternatively, thebase45 can be formed in the first molding process and the catheter can be formed and attached to the base45 in the second-shot molding process. The injection molding of components may reduce costs by simplifying the manufacturing process.
• In a single-shot molding process, a polymer is heated to a temperature suitable for the process and injection molded to form a first element (e.g., a catheter). If an additional molding process is required in order to add a second element (e.g., a base) to the first element, the same or a different polymer can be heated to a temperature suitable for a second-shot molding process and injection molded to form the second element. The second-shot molding process also fuses the first element to the second element. The polymers used in the molding processes can utilize same or different materials and they can have the same color or different colors if desired to clearer visual identification. A preferred polymer for injection molding the catheter is Teflon®. If Teflon® is used to injection mold the catheter, the base can also be made of Teflon® or another polymer, e.g., a polyurethane product such as Vialon™ biomaterial by Becton, Dickinson and Company (BD).
• The catheter can also be formed using a multiple-shot molding process, in which various components can be molded in sequence. For instance, the catheter tube and adapter could be made from different materials using a two-shot molding process.
• The embodiment ofFIG.6 illustrates a catheter infusion set that features manual insertion and needle removal via thecatheter43, followed by attachment of a removable infusion fluid connector and tube set (not shown).
• InFIG.6, the one-piece catheter40, preferably molded using a polymer such as Teflon®, includes a base45 made of the same polymer or a different polymer if a two-shot molding process is used. Aseptum70 is placed in the main cavity of theadapter41, through which anintroducer needle60 is shown penetrating. Theintroducer needle60 is shown in its housing, the needle handle orbase50. Theintroducer needle60 attached to the needle handle50 is detachable from thecatheter40. Thecatheter40 includes aretention ring46 that connects theadapter41 to thebase45. Theadapter41 may include a slotted ring-like structure orflange413 that can attach to or connect to a tube set connector (not shown) to receive fluid into the adapter such that the fluid can flow through thecatheter tube43.
• The connection between theadapter41 to thecatheter tube43 in the embodiment illustrated inFIG.6 is similar to that ofFIG.5. At a lower portion of theadapter41, there is a funnel-shaped lead-inportion411 having an apex412. At the apex412, andend portion432 of thecatheter tub43 is connected to theadapter41. The opendistal tip431 of thecatheter tube43 is also illustrated inFIG.6, through which fluid flows outward from the inner walls of theadapter41 through the lead-inportion411 and thecatheter tube43. Askin adhesive460 detachably attaches the base45 to a user. Thecatheter40 can be formed in a single-shot molding process and the base45 can be formed by a second-shot molding process, to form the catheter-base structure.
• FIG.7 is a cross-sectional view of an exemplary infusion set, wherein the infusion set100 utilizes another one-piece catheter101 in accordance with an exemplary embodiment of the present invention. Thecatheter101 can be used as replacement for a conventional catheter having multiple components, as described above.FIG.7 further illustrates a fluid connector or tube set102 with ablunt cannula103 of thehub12′ piercing aseptum104 housed in the adapter/base104 of thecatheter101, such that when thehub12′ is removed from the base19′, theseptum104 self-closes to prevent entry of foreign particles into thecatheter101. When thehub12′ is attached to the base19′, a fluid path is formed from the tube set102 to theexternal tip105 of thecatheter101.
• FIGS.8A and8B further illustrate another exemplary infusion set300, in which a one-piece catheter3320 similar to that ofFIG.7 is utilized. InFIG.8A, the user can attach or detach thehub360 to or from thebase380. Thehub360 includes alocking ring362 withtabs364 that secure tocorresponding slots382 of the base330. After thetabs364 are inserted into theslots382, the user can rotate thehub360 to interlocktabs364 to thebase380. A catheter3320 is secured to the base3350.FIG.8B is a cross-sectional view of the infusion set ofFIG.8A. Askin adhesive390 detachable attaches the base380 to a user. As illustrated inFIG.8B, thecatheter101 includes a cylindrical main cavity in which theseptum104 is received. When thehub360 is attached to thebase380, theblunt cannula366 of thehub360 penetrates theseptum104, to permit liquid medication to be pumped into thecatheter104. Liquid medication is pumped from the pump (not shown) through the tube set16′ and into theblunt cannula366, and exits thecatheter104.
• FIGS.9A and9B illustrate how an exemplary one-piece catheter400 in accordance with an embodiment of the present invention, housing aseptum402 in the adapter portion thereof, can be used with anintroducer500 having aneedle handle520 with anintroducer needle502, above a base600 to which askin adhesive610 is attached. Theintroducer500 is spring-loaded and ready to be released to insert thecatheter400 and theintroducer needle502 into a user.FIG.9B shows greater detail of the spring-loadedmechanism510 that when actuated, inserts thecatheter400 and theintroducer needle502 in to a user.
• FIG.10 illustrates the insertion of a one-piece catheter400′, one that is similar to the embodiment ofFIGS.9A and9B, in which the one-piece catheter400′, as well as anintroducer needle502′, is inserted into a user by releasing a spring-loadedmechanism510′ of theintroducer500′. Upon insertion of theintroducer needle502′ and thecatheter400′ to a user, theintroducer500′ and theintroducer needle502′ are then removed from thecatheter400′ which is locked or lockable to a base600′, as illustrated.
• There are many advantages of a one-piece catheter. For instance, the overall strength of the one-piece catheter can generally be stronger than a conventional multi-piece assembly that utilizes polymeric and metal components. In addition, by eliminating numerous components of different materials, sizes and shapes, there is a reduction in manufacturing cost. Additionally, in exemplary embodiments of the one-piece catheter of the present invention, since there are no connection junctions, as in the frictional engagement of the conventional catheter to the conventional wedge, which minimizes the likelihood of leaks that may otherwise occur at such junctions. Further, the exemplary one-piece catheter can more evenly transmit impact forces onto the overall catheter as the catheter is inserted into a user, as compared with a conventional multi-component catheter, such that the one-piece catheter can be inserted without being weakened at any particular location, as would be the case in a conventional, multi-component catheter.
• Although only a few exemplary embodiments of the present invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the appended claims and their equivalents.

Claims (5)

1. A method of making a catheter, comprising the steps of:

heating a polymer to a desired temperature; and

injection molding the heated polymer to form a one-piece catheter comprising a catheter tube connected to an adapter with a retention tab for attaching to a base.

2. The method as claimed inclaim 1, wherein the injection molding is a one-shot process to form the catheter.

3. The method as claimed inclaim 1, further comprising the steps of:

heating a second polymer to a desired temperature;

injection molding the second polymer to form the base fused to the retention tab of the catheter.

4. The method as claimed inclaim 1, wherein the first and second polymers are the same material.

5. The method as claimed inclaim 1, wherein the first and second polymers are different material.

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