PREFORM FOR BLOW MOLDED SYRINGE FOR USE WITH INJECTORS

Abstract

A syringe for use in a pressurized injection of a fluid includes a syringe barrel including a polymeric material having undergone expansion via blow molding. A preform for blow molding a blow molded syringe is described, the preform including a proximal end having a retention mechanism adapted to connect to the syringe to a powered injector, a distal end having a syringe outlet section, and a barrel section between the retention mechanism and the syringe outlet section, wherein the barrel section is adapted to be blow molded to form a cylindrical wall of a syringe barrel defined between the retention mechanism and the syringe outlet section.

Claims

1. A preform for a stretch blow molded syringe, the preform comprising: a proximal end having a retention mechanism, the retention mechanism adapted to connect the syringe to a powered injector; a distal end having a syringe outlet section; and a barrel section between the retention mechanism and the syringe outlet section, wherein the preform comprises at least one polymeric material, and wherein the barrel section is adapted to be stretch blow molded to form a cylindrical wall of a syringe barrel defined between the retention mechanism and the syringe outlet section, and wherein the syringe outlet section in formed during an injection molding process of the preform and is not substantially altered during a stretch blow molding expansion process.

2. The preform of claim 1, wherein the retention mechanism is formed during an injection molding process of the preform.

3. The preform of claim 2, wherein the retention mechanism is not substantially altered during the stretch blow molding expansion process.

4. The preform of claim 1, wherein the syringe outlet section comprises a connector adapted to connect with a complementary connector of a fluid path element.

5. The preform of claim 4, wherein the connector is one of a male luer connector or a female luer connector.

6. The preform of claim 4, wherein the connector comprises an outlet passage.

7. The preform of claim 1, wherein the at least one polymeric material of the preform comprises at least one of polyethylene terephthalate, cyclic olefin polymer, polypropylene, polystyrene, polyvinylidene chloride, polyethylene naphthalate, or nylon.

8. The preform of claim 1, wherein the preform comprises a first layer of a first polymeric material and at least a second layer of a second polymeric material, wherein the second polymeric material is different from the first polymeric material.

9. The preform of claim 1, further comprising a transition region between the barrel section and the syringe outlet section of the preform, wherein the transition region forms a conical section between the cylindrical side wall and the syringe outlet section of the stretch blow molded syringe.

10. The preform of claim 1, wherein the barrel section is adapted to be stretch blow molded to form the cylindrical wall of the syringe barrel, wherein the cylindrical wall has an inner diameter that is substantially constant.

11. The preform of claim 10, wherein the inner diameter of the cylindrical wall does not vary by greater than 0.01 inches.

12. The preform of claim 10, wherein the cylindrical wall of the syringe barrel is less than 0.07 inches in thickness.

13. The preform of claim 1, wherein the preform is adapted to be biaxially stretched during stretch blow molding.

14. A preform for a stretch blow molded syringe, the preform comprising: a proximal end having a retention mechanism; a distal end having a syringe outlet section; and a barrel section between the retention mechanism and the syringe outlet section, wherein the barrel section is adapted to be stretch blow molded to form a cylindrical wall of a syringe barrel defined between the retention mechanism and the syringe outlet section, wherein the retention mechanism remains on the syringe after stretch blow molding and is adapted to connect the syringe to a connection mechanism of a powered injector.

15. The preform of claim 14, wherein the barrel section is adapted to be stretch blow molded by biaxial stretching.

16. A method for stretch blow molding a preform to produce a stretch blow molded syringe, the method comprising: providing an injection molded preform comprising: a proximal end having a retention mechanism formed during an injection molding process of the preform, the retention mechanism adapted to connect the syringe to a powered injector; a distal end having a syringe outlet section formed during the injection molding process of the preform; and a barrel section between the retention mechanism and the syringe outlet section; and stretch blow molding the preform to provide a stretch blow molded syringe having a biaxially stretched cylindrical side wall between a syringe proximal end comprising the syringe retention mechanism and a syringe distal end comprising the syringe outlet section, wherein the syringe outlet section and the retention mechanism are not substantially altered during the stretch blow molding step.

17. The method of claim 16, wherein stretch blow molding the preform comprises blowing compressed air into the preform through the syringe outlet section.

18. The method of claim 16, wherein the stretch blow molded syringe comprises a rearward, monolithic closure.

19. The method of claim 16, wherein the injection molded preform further comprises a transition region between the barrel section and the syringe outlet section, wherein the transition region forms a conical section between the cylindrical side wall and the syringe outlet section of the stretch blow molded syringe.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other aspects of the disclosure and their advantages will be discerned from the following detailed description when read in connection with the accompanying drawings, in which:

[0030] FIG. 1A illustrates an embodiment of a preform of the present disclosure.

[0031] FIG. 1B illustrates the stretch blow molding of the preform of FIG. 1A into a mold to form a syringe.

[0032] FIG. 1C illustrates a side, cross-sectional view of the syringe of FIG. 1B.

[0033] FIG. 1D illustrates a cross-sectional enlargement of the rearward end of the syringe of FIG. 1C.

[0034] FIG. 1E illustrates a cross-sectional enlargement of the forward end of the syringe of FIG. 1C.

[0035] FIG. 1F illustrates a perspective view of the syringe of FIG. 1C.

[0036] FIG. 1G illustrates a front view of the syringe of FIG. 1C.

[0037] FIG. 2A illustrates another embodiment of a preform of the present disclosure.

[0038] FIG. 2B illustrates the stretch blow molding syringe formed from the preform of FIG. 2A with the stretch rod therein.

[0039] FIG. 2C illustrates an enlargement of the rearward end of the syringe of FIG. 2B.

[0040] FIG. 2D illustrates a side view of the stretch rod.

[0041] FIG. 2E illustrates a side cross-sectional view of the syringe of FIG. 2B.

[0042] FIG. 2F illustrates a cross-sectional enlargement of the syringe of FIG. 2B.

[0043] FIG. 2G illustrates the stretch blow molding syringe of FIG. 2A within the mold therefor.

[0044] FIG. 2H illustrates the syringe of FIG. 2B in operative connection with an injector.

[0045] FIG. 2I illustrates a blow molded fluid path element of the present disclosure including a precision molded Luer connection in the vicinity of one of two openings thereof and a precision molded threading connection in the vicinity of the other of the two openings.

[0046] FIG. 2J illustrates a blow molded manually operated syringe of the present disclosure.

[0047] FIG. 3A illustrates another embodiment of a syringe of the present disclosure including an integral syringe tip closure.

[0048] FIG. 3B illustrates an enlarged view of the syringe tip of the syringe of FIG. 3A.

[0049] FIG. 4A illustrates another embodiment of a syringe of the present disclosure including an integral rearward closure.

[0050] FIG. 4B illustrates an enlarged view of the rearward section of the syringe of FIG. 4A.

DETAILED DESCRIPTION

[0051] In general, the present disclosure provides hollow article devices such as syringes and methods of manufacture of such devices using blow molding processes. The present disclosure is discussed below primarily with reference to representative embodiments of syringes for injection of a fluid into a patient. However, one skilled in the art appreciates that the methods of the present disclosure can be used to form a number of hollow article devices (including, for example, medical flow path elements or devices).

[0052] Blow molding is a method of forming hollow articles from polymeric (thermoplastic) materials. Simplifying, the blow molding process involves forming a heated tube within a mold cavity using a pressurized gas (typically, compressed air). The three most common methods of blow molding are extrusion blow molding, injection blow molding and injection-stretch blow molding. In extrusion blow molding, tubes or parisons are extruded into alternating open mold halves and then blown and cooled prior to removal from the mold. In injection blow molding, a preform component is first injection molded. The preform is then blown to the product's final shape. Injection blow molding can provide dimensional precision in certain critical areas. The injection blow molding process can be performed using separate machines or through use of shuttling or rotating molds. In the injection-stretch blow molding process, a preform is, once again, first injection molded. During subsequent blowing, however, the preform/parison is mechanically extended at an optimal temperature, while radially blown to shape within the mold. Injection-stretch blow molding provides a biaxial stretch to enhance material properties. For example, the biaxial orientation can increase tensile strength by an order of five or more. Furthermore, biaxial orientation can enhance other material properties, such as clarity, barrier properties (2 or more), and mechanical properties. For example, crystallinity of certain polymers can be controlled. In several embodiments for syringes of the present disclosure manufactured from, for example, polyethyleneterephthalate, crystallinity can be increased to as high as approximately 43% (for example, via mechanical and/or thermal processing) to maximize these improvements. One skilled in the art also realizes that further increasing crystallinity can be detrimental and decrease optical properties and cause the material to be too brittle.

[0053] The present inventors have discovered that the improved mechanical properties provided by blow molding of, for example, syringes can enable a decrease in the barrel wall thickness of a syringe as compared to an injection molded syringe while maintaining an acceptable safety factor over a range of operating pressures. Moreover, use of a blow molding process in the manufacture of syringes and other devices can substantially increase manufacturing throughput. Indeed, significant reduction in manufacturing cost can result from using a blow molding process to manufacture syringes for use with powered injectors and non-powered or manually powered syringes. Likewise, significant reduction in manufacturing cost can result from using a blow molding process to manufacture other devices including, but not limited to, hollow devices used in flow paths for medical fluids.

[0054] FIGS. 1A through 1G illustrate one embodiment of a preform 10 and a blow molded, closed-ended syringe 10 that was used in several studies of the present disclosure. Preform 10 was first molded using an injection molding process. The injection molding process facilitates the formation of areas wherein dimensions are critical (that is, areas in which certain dimensional tolerances must be maintained), such as the injector or other attachment mechanism 20 on the rearward end of preform 10. In the embodiment of FIGS. 1A through 1G, injector attachment mechanism 20 includes a flange 22 that extends around the circumference of preform 10 and syringe 10. Preform 10 and syringe 10 also include a drip flange 30 that cooperates with a front wall of an injector (not shown) to, for example, assist in accurately positioning syringe 10 within the injector and to prevent fluids from entering the injector housing. Injector attachment or mounting flange 22 and drip flange 30 remain essentially unchanged from preform 10 to blow molded syringe 10. Syringes including such an injector attachment design and injectors for use therewith are described, for example, in U.S. Pat. Nos. 5,383,858 and 6,665,489, the disclosures of which are incorporated herein by reference. As further discussed below, one skilled in the art appreciates that syringes having virtually any type of attachment mechanism and/or one or more other precision molded, elements portions or sections can be manufactured using the methods and systems of the present disclosure.

[0055] FIG. 1B illustrates preform 10 within a mold 100 in which it undergoes stretch blow molding to result in syringe 10. In FIG. 1B, preform 10 is illustrated in thickened lines for clarity. Likewise, barrel 12 of syringe 10 is illustrated in thickened dashed lines for clarity. Barrel 12 included a forward closed end 14 in this embodiment. Mounting flange 22 and drip flange 30 cooperated with corresponding retaining flanges in mold 100 to retain the rearward end of preform 10 and syringe 10 throughout the stretch blow molding process. Once again, mounting flange 22 and drip flange 30 (and/or other molded elements which are molded to have certain dimensions and associated tolerances) remain essentially unchanged during the stretch blow molding process. In that regard, it may be desirable to maintain the preheat temperature in the rearward portion of preform 10 and syringe 10 relatively cool (below the T.sub.g of the material) as compared to the remainder of the mold to prevent deformation of mounting flange 22 and drip flange 30 (and/or other elements) during the blowing process. Heat shielding can also be used. In general, those sections of mold 100 forward of drip flange 30 are preheated in a preheating unit to a temperature sufficiently high to maintain the temperature of the preform/syringe above the glass transition (T.sub.g) of the thermoplastic during the molding process. After preheating, preform 10 is placed into mold 100. In several studies of the present disclosure, there was no further heating in mold 100. In a number of studies of the present disclosure, polyethyleneterephthalate (PET) or cyclic olefin polymer (COP) was used. The COP used was ZEONOR 1410R available from Zeon Chemicals LP of Louisville, Ky. COP is, for example, suitable for sterilization (for example, high energy sterilization (such as radiation), chemical sterilization (such as ethylene oxide), autoclave sterilization and/or steam sterilization) and can, for example, be used in connection with prefillable syringes. As clear to one skilled in the art, a variety of polymeric materials can be used in the devices, systems and methods of the present disclosure. In general, materials that can undergo orientation (for example, biaxial orientation) during the molding process can be preferred in certain uses because of the enhanced properties exhibited by such materials. In addition to PET and COP, such materials include, but are not limited to, polypropylene, polystyrene and polyvinylidene chloride (PVDC).

[0056] As described above, during the stretch blow molding process, stretch rod 320 is extended forward, while compressed air is blown into the interior of preform 10 until preform 10 is expanded to fill the mold cavity, thereby forming syringe 10 including barrel 12 in which the thermoplastic is biaxially oriented (that is, oriented axially or in the direction of axis A and radially/tangentially or in a direction normal or around to axis) as described above. In this embodiment, stretch rod 320 pushes against closed end 14 during the blow stretch molding process. Upon cooling, syringe 10 is removed from mold 100.

[0057] To achieve high pressures, smooth plunger movement within the syringe, limit blow by, and/or provide predictable volume in the syringes of the present disclosure, it is desirable to have an inner diameter in the syringe barrel having a relatively consistent wall thickness. To ensure a relatively consistent wall thickness and therefore a predictable, relatively consistent interior syringe barrel diameter with adequate strength, the preform design is important. For example, the area in front of the drip flange 30 may undergo a stretch of up to four (4) times its original length and width in preform 10 to meet the final dimensions in syringe 10. If the material stretches unevenly as a result of design or heating limitations, such stretching variability must be provided for in the preform design. For example, additional material may be required in areas of high stretch. On the other hand, reduced material may be required in areas of low stretch. Alternatively or additionally, the rate or speed of stretch, the preform temperature, and blow pressure can be varied. The inventors of the present disclosure have discovered that relatively consistent and predictable wall thickness and internal diameter can be readily achieved in blow molded syringes. The process considerations set forth above are known to those skilled in the blow molding arts and can result in a syringe barrel compatible with high-pressure (for example, 50 psi to 1500 psi) use and adequate/predictable fluid performance. An example of an acceptable delivery volume tolerance in an injection system is approximately 2%+1 mL. In meeting a suitable delivery volume tolerance, the inner diameters of the syringes of the present disclosure preferably do not vary by greater than 0.01 inches. Variances of no greater than 0.007 inches in inner diameter are also achievable. Indeed, variances of no greater than 0.004 inches in inner diameter are also achievable over the pressurizing zone of the syringe.

[0058] In several studies of the syringes of FIGS. 1A through 1B, 60 blow molded syringes were used and divided into 3 lots of differing PET fabrication material of 20 syringes each. Preferably, the PET material exhibited partial crystallinity after blow molding. The three PET materials used to fabricate the syringes EN001 PET, EN063 PET and HW CF746 PET, available Eastman Chemical of Kingsport, Tenn. The syringes tested had a wall thickness of approximately 0.030 in. In pressure testing the syringe, triple seal RTF plunger as described, for example, in U.S. Pat. Nos. 5,873,861, 6,017,330 and 6,984,222, the disclosures of which are incorporated herein by reference. Many other plungers, including other dynamically sealing plungers as, for example, described in U.S. Pat. No. 6,224,577, the disclosure of which is incorporated herein by reference, can also be used effectively in the syringes of the present disclosure. A universal tensile testing machine available from Instron of Norwood, Mass. was used in the testing. Samples for tensile strength testing were cut for testing using a die as known in the art. Several properties of the PET materials studied in the present disclosure are set forth below in Table 1 as determined using the test conditions and procedures of ASTM D 638, the disclosure of which is incorporated herein by reference. In the case that PET polymers or copolymers are used, such polymer can, for example, have an intrinsic viscosity in the range of 0.65 to 1.04 dl/g (deciliters/gram). As known in the art, intrinsic viscosity is dependent upon the length of the polymer chains of the polymer.

TABLE-US-00001 TABLE 1 EN001 EN063 HW CF746 Stress @ yield (psi) 8,400 8,400 not available Stress @ break (psi) 3,600 4,600 not available Modulus (psi) 350,000 360,000 not available

[0059] Static high pressure testing was performed at 2 mL/s for 5 samples from each lot using water. In the static high pressure test, each syringe was filled to just below drip flange (approximately 75% full). The plunger was then installed. The syringe was retained in a holding fixture in the Instron universal tensile testing machine while a measurable force was applied to plunger. The Instron universal tensile testing machine, which was calibrated for flow rate, was set at 2 ml/sec and failure mode was recorded. Three PET material types, as described above, were tested. The static high pressure testing resulted in an average pressure of 342 psi with a standard deviation of 40 psi for EN001 PET. Failure modes were barrel burst and blow by. The static high pressure testing resulted in an average pressure of 310 psi with a standard deviation of 171 psi for EN063 PET. Potential failure modes were barrel burst and blow by. The static high pressure testing resulted in an average pressure of 305 psi with a standard deviation of 67 psi for HW CF746 PET. The failure mode was barrel burst.

[0060] Dynamic pressure testing was performed at 5 ml/s for 5 samples from each lot using saline. Dynamic pressure and capacitance testing were performed only for EN001 PET as the force to fail was the largest for that material of the three material types tested. In these tests, closed end 14 of syringes 10 was drilled out and a metal luer connection was connected. A flow restrictor valve was connected to the luer connection. The Instron was set at 5 ml/sec. The flow restrictor valve was adjusted to generate a pressure of 100 psi. The average dynamic friction force was 50 lbs or 18.7 psi at a syringe pressure of 100 psi.

[0061] In tensile strength testing, samples were first cut out using the tensile bar cutting die. Tests were then performed in accordance with the testing procedures set forth in ASTM D638. Samples were cut radially (5 samples of each lot) as well as axially (5 samples of each lot). FIG. 1E illustrates generally how axial and radial samples were cut from syringes 10. The results of several tensile strength studies are set forth in Table 2.

TABLE-US-00002 TABLE 2 Maximum Stress @ Stress @ Stress Break Yield Modulus Strain @ Strain @ (psi) (psi) (psi) (psi) Break Yield 001 Axially 16546 16216 10842 475964 52 3 001 Radially 9146 5095 8914 344345 31 4 063 Axially 13990 9632 11146 485791 39 3 063 Radially 9214 1594 9196 353298 25 4 HW Axially 12024 7670 10409 527765 29 3 HW Radially 8440 4360 7642 527413 18 3

[0062] In several capacitance testing studies of the syringes of the present disclosure, a metal luer was installed in syringes 10 as described above, and syringes 10 were filled with water. A rubber O-ring plunger was inserted and the plunger was advanced until the front of the plunger was approximately 1 inch past drip flange 30. Syringe 10 was then mounted onto the Instron. The Instron was set to run at 2 in/min and to stop at a load of 540 lbs. A 3-way stopcock was installed on the end of the syringe, and a scale was placed under the syringe with a beaker to capture the fluid. A piece of connector tubing was attached to the metal luer fitting that was of sufficient length to reach into the beaker. Care was taken so that the tubing did not come in contact with the beaker. The Instron was then run. When the 540 lb limit was reached, the stopcock was turned slowly to dispense the fluid into the beaker. Subsequently, the stopcock was returned to the closed position to dispense the remaining fluid out of the line. The volume of fluid dispensed into the beaker was recorded. The results of several studies are set forth in Table 3.

TABLE-US-00003 TABLE 3 Syringe # Fluid Dispensed 73 6.3 ml 94 6.6 ml 74 4.8 ml 71 6.3 ml

[0063] In general, neither the tested syringes nor the method of manufacture was optimized in the above studies. The failure mode observed during the burst pressure tests, were almost all a result of splitting at the blow mold parting line. The blow mold parting line is the split between the mold halves. A non-optimized parting line can cause undue material stress and malformation, which may weaken this area. Optimizing the parting line (which was not done in the present studies) can, for example, be accomplished by ensuring a minimal mismatch and sharp clean edges on the parting line of the blow molding tool. The friction force and static pressure were found to be relatively consistent in the tested syringe with the highest level of consistency realized with the EN001 material. The data suggested that the blow-up ratio to tensile strength is a linear function, which correlates with published information on injection-stretch blow molding. These results reflect a 2 to 1 ratio on the axial dimension and a 1 to 1+ on radial dimensions. The EN001 material exhibited the highest increase. The friction force was found to consistent along the length of the barrel. Moreover, the barrel wall thickness was consistent, as interpolated from the friction data.

[0064] A heat setting process as known in the blow molding arts (effected, for example, via heating the blow mold cavities to elevated temperatures) may be desirable, for example, in the case that ethylene oxide (EtO) sterilization is to be used, as a result of the elevated temperatures used during EtO sterilization. The elevated temperatures of the EtO sterilization process may cause the suitable or acceptable dimension of the syringe barrel internal diameter to relax or change to an unacceptable dimension. The syringe plunger, which is sealingly and slidably positioned within the syringe barrel, exerts an outward force to ensure an adequate seal against the barrel wall to prevent leakage when pressurized during use. The heat setting process prevents the barrel wall from expanding or contracting and changing to an unacceptable dimension. It is not believed that a heat setting process will be required to control or improve the fluid capacitance of the syringe barrel. However, the results indicate that syringe fluid capacitance can also be improved with blow molding (for example, via heat setting), as compared to injection molding even with a relatively thin wall. The wall thickness of the syringes studied in the present disclosure was approximately 0.030 inches (versus, for example, approximately 0.79 for a typical injection molded syringe). The pressure capability of the syringe barrel can, for example, be improved by using a preform which exhibits a higher stretch ratio with the same wall thickness. The preform design can also be improved or optimized to, for example, take advantage of the PET self-leveling material characteristics, which will improve dimensional consistency and increase overall material strength. In general, self-leveling is the ability for the polymer to stretch, such that it pulls from a thicker cross section instead of a thinner cross section. If the cross section is properly sized to the total expansion, the final component will exhibit a consistent wall thickness.

[0065] FIGS. 2A through 2H illustrate another embodiment of a preform 210 and a blow molded, open-ended syringe 210. As with preform 10, preform 210 is first molded using an injection molding process. The injection molded process facilitates the formation of areas in which dimensional tolerances are critical such as the injector attachment mechanism 220 on the rearward end of preform 210. In the embodiment of FIGS. 2A through 2H, injector attachment mechanism 220 includes a flange 222 that extends around the circumference of preform 210 and syringe 210. In the illustrated embodiment, preform 210 and syringe 210 also include a drip flange 230. Syringe 210 can alternatively or additionally include other precision molded portions or sections. Once again, injector attachment or mounting flange 222 and drip flange 230 (and/or other precision molded portions) remain essentially unchanged from preform 210 to blow molded syringe 210. A stretch rod 320 can be incorporated into the blowing mold process to induce biaxial orientation and to assist in, for example, ensuring that premolded features forward of the portion of preform 210 to be expanded such as illustrated in FIG. 2F and discussed further below are not harmed (for example, that the dimensions thereof are not substantially altered and required tolerances are maintained) during the blowing molding process. After the preform 210 is preheated as described above and placed into the blowing mold, two halves 305 of the blowing mold (see FIG. 2G) are closed. When properly clamped, stretch rod 320 is moved linearly to engage tip 330 into the internal aspect of syringe tip 214. Stretch rod 320 continues to move forward forcing syringe tip 214 into a protected mold area shaped in the form of syringe tip 214 and/or other forward precision molded component (see FIG. 2G). This area of the mold as well as the area encompassing mounting flange 222 and drip flange 230 can be maintained below molding temperature, so that the dimensions of the premolded syringe tip 214, the premolded mounting flange, and the premolded drip flange 230 are not affected/altered.

[0066] Similar to preform 10, preform 210 is placed within the mold, as illustrated in FIG. 2G, in which it undergoes stretch blow molding to result in syringe 210. Preform 210 and syringe 210 included forward, open-ended syringe tip 214 including a syringe outlet 214a having an integrally or monolithically formed, precision molded connector such as a connector including a male luer taper and a luer threading 214b in the illustrated embodiment. Barrel 212 is connected to syringe tip 214 by a rounded (in cross section) transition region 216. Mounting flange 222 and drip flange 230 cooperate with corresponding retaining flanges in the mold to retain the rearward end of preform 210 and syringe 210 throughout the stretch blow molding process.

[0067] As described above, during the stretch blow molding process, stretch rod 320 is extended forward, while compressed air is blown into the interior of preform 210 until preform 210 is expanded to fill the mold cavity, thereby manufacturing syringe 210 including barrel 212 in which the thermoplastic is biaxially oriented. In this embodiment, stretch rod 320 includes a forward section 330 dimensioned to enter and at least partially seal the rearward portion of syringe tip 214 (from fluid connection with the portion or preform 210 being expanded), thereby assisting in maintaining pressure within expanding barrel 212. Stretch rod 320 also pushes against syringe tip 214 during the blow stretch molding process as described above to, for example, assist in achieving biaxial orientation. Moreover, stretch rod 320 at least partially prevents heated gas from entering syringe tip 214, (which is injection molded during fabrication of preform 210 to predefined acceptable tolerances), thereby assisting in maintaining syringe tip 214 essentially unaltered during the blow molding process.

[0068] FIG. 2H illustrates syringe 210 in operative connection with an injector including a controller and a motor in operative connection with the controller to control the powered motion of a drive member or piston 350 in operative connection with syringe plunger 250 which is slidably positioned within syringe barrel 212. As described above, injectors suitable for use with various syringes of the present disclosure are disclosed, for example, in U.S. Pat. No. 5,383,858 and U.S. Pat. No. 6,652,489.

[0069] FIG. 2H also illustrates that the wall of syringe 210 can include a first layer 212a of a first polymeric material and at least a second layer 212b of a second polymeric material, different from the first polymeric material. At least one of the first polymeric materials can, for example, include polyethyleneterephthalate, cyclic olefin polymer, polypropylene, polystyrene, polyvinylidene chloride, polyethylene naphthalate and/or nylon. The second polymeric material can, for example, be nylon, ethylene vinyl alcohol copolymer (EVOH), polycarbonate or other suitable polymers as known in the art. EVOH, for example, provides good barrier properties and may be used in connection, for example, with prefillable syringes. The first and/or the second polymeric material can, for example, include a single polymer or blends of two or more polymers. The polymeric materials of the first layer and the second layer can, for example, differ in one or more respects such as composition, molecular weight, crystallinity, barrier properties etc. As known in the blow molding arts, an adhesive or tie layer 212c can be used between polymeric layers to strengthen the bond between such layers. Suitable adhesives or tie layers include those known in the art that are useful in adhering layers of dissimilar polymeric materials and in achieving an improved interlayer bond strength. An example of a suitable adhesive or tie layer material is ADMER (a modified polyolefin with functional groups available from Mitsui Chemicals America, Inc. of Rye Brook, N.Y.) that is suitable to bond to a variety of polymers including, for example, polyolefins, ionomers, polyamides, ethylene vinyl alcohol (EVOH), PET, polycarbonates, and polystyrenes.

[0070] In general, the process described above in connection with the syringe of FIGS. 2A through 2H can be used to create any hollow device or apparatus that is open at both ends via a blow stretch molding process. The process is thus well suited for fabricating many fluid flow path elements used, for example, in the medical arts. As used herein, the term flow path element refers generally to any device or element through which a fluid (for example, a liquid and/or gas) flows (for example, in a medical system). Such flow path elements are open at each end and at least one end thereof, and often each ends thereof, includes an attachment mechanism and/or or other portion or section molded to certain predefined acceptable tolerances to, for example, enabling attachment of the flow path element to other devices and/or flow path elements. As known in the art, connector or attachment mechanisms can take a wide variety of forms (for example, threaded attachments, snap attachments, friction attachments, Luer attachments, plug fits etc.). As also known in the art, it is desirable to mold such connector or attachment mechanism or mechanisms within specific tolerances to, for example, ensure a non-leaking, high-pressure seal. As described above, the blow stretch molding processes and systems of the present disclosure are well suited to expand the intermediate portion or section of the device or flow path element while the dimensions and other properties of the precision molded portions on one or both ends of the device are essentially unaltered. In that regard, the blow stretch molding methods and systems of the present disclosure are suited to maintain common production tolerances (both fine and commercial standards) for a wide variety of polymeric materials as described, for example, in Whitmore, E. M., editor, Standards & Practices of Plastics MoldersGuidelines for Molders and Their Customers, Molders Division, Sponsored by the Society of the Plastics Industry, Inc. (1993). The blow stretch molding methods and systems of the present disclosure are, for example, suitable to maintain tolerances of end attachments or other molded features to plus or minus 0.05, 0.02, 0.01, 0.005 and even 0.002 for a variety of polymeric materials.

[0071] FIGS. 2I and 2J illustrate examples of fully formed flow path elements and devices that can be fabricated using the blow stretch molding methods of the present disclosure. FIG. 2I illustrates a flow path element 360 (for example, a drip chamber) having an inlet 362 and an outlet 364. Each of inlet 362 and outlet 364 are injection molded to incorporated precision molded connection or attachment mechanisms before the blow stretch molding process. In that regard, inlet 362 includes a threaded connection in the vicinity thereof, and outlet 364 includes a male Luer connection in the vicinity thereof. The dimensions/tolerances of the precision molded connection mechanisms (and/or other precision molded components) are essentially unaltered during the expansion of intermediate (hollow) section 366 during the blow stretch molding process.

[0072] FIG. 2I illustrates an embodiment of a low-pressure, manually operated syringe 370 formed by a blow stretch molding process of the present disclosure. Syringe 370 includes a rearward or proximal opening 372 and a forward or distal outlet 374 in the form of a male Luer fitting. A manually operated plunger extension 380 connects to syringe plunger 382 slidable positioned within syringe barrel 376 through rearward opening 372. Syringe 370 further includes finger grips 378. The dimensions/tolerances of the Luer connector finger grips 378 are essentially unaltered during the expansion of syringe 376 during the blow stretch molding process.

[0073] FIGS. 3A and 3B illustrate another embodiment of a syringe 410 of the present disclosure which is blow molded from a preform (not shown). In this embodiment, syringe 410 includes a rear mounting flange 422 and a forward syringe tip 414 that remain essentially unchanged during the blow molding process. As described above, barrel 412 and transition region 416 are expanded to fill the mold cavity during the blow molding process.

[0074] In this embodiment, syringe tip 414 includes an integrally molded syringe tip closure 418 that is molded integrally with syringe tip 414 during the injection molding of the preform. Syringe tip closure 418 can, for example, be connected to syringe outlet 414a via an area of reduced wall thickness 419 so that syringe tip closure 418 can be readily broken off to open syringe outlet 414a. Syringe tip closure 418 can, for example, assist in maintaining sterility in the case of a prefilled syringe. The integrally molded syringe tip closures of the present disclosure can also be provided on syringes that are not blow molded (for example, injection molded syringes).

[0075] FIGS. 4A and 4B illustrate another embodiment of a syringe 510 of the present disclosure blow molded from a preform (not shown). In this embodiment, syringe 510 includes a rear mounting flange 522 and a forward syringe tip 514 that remain essentially unchanged during the blow molding process. As described above, barrel 512 and transition region 516 are expanded to fill the mold cavity during the blow molding process. In the embodiment of FIGS. 4A through 4B, compressed air can, for example, be blown into the preform through syringe tip 514a to create the rearward, integral or monolithic closure/plunger cover 540 in a blow molding process. Extrusion blow molding can, for example, be used in this embodiment.

[0076] With reference to FIG. 4B, in several embodiments, closure 540 is removable at edges 542 thereof (for example, via areas of reduced wall thickness, channels, notches etc.) from the connection with the remainder of syringe 512. As described above, the removable closure can, for example, form a plunger section upon removal from connection with the remainder of syringe 512. Plunger or plunger cover 540 forms a substantially sealing engagement with the inner wall of syringe 512 when slid through the barrel thereof. In the illustrated embodiment, plunger 540 includes a flange 544 attached at a rearward portion of flange 544 to body or central portion 548 of the plunger 540. Flange 544 extends forward and radially outward to form a circumferential channel 546 between flange 544 and body 548 of plunger 540. During use of syringe 512, fluid within syringe 512 enters annular channel 546. Forward motion of plunger 540 to pressurize and inject fluid contained within syringe 512 results in pressurization of the fluid within annular channel 546. The hydraulic force of the fluid within annular channel 546 forces flange 544 away from body portion 548 and against an inner wall of syringe 512. As plunger 540 is moved forward, flange 544 is forced against the inner wall of syringe 512 and prevents any fluid from passing rearward between flange 544 and the inner wall of syringe 512. The operation of plungers including such a wiper seal is discussed, for example, in U.S. Pat. No. 6,224,577.

[0077] Although the present disclosure has been described in detail in connection with the above embodiments and/or examples, it should be understood that such detail is illustrative and not restrictive, and that those skilled in the art can make variations without departing from the disclosure. The scope of the disclosure is indicated by the following claims rather than by the foregoing description. All changes and variations that come within the meaning and range of equivalency of the claims are to be embraced within their scope.