U.S. patent application number 11/664236 was filed with the patent office on 2008-05-01 for method for reducing or eliminating residue in a glass container and a glass container made in accordance therewith.
Invention is credited to Bruno Cocheteux, Arturo Cortes, Richard Dale Luedtke, Patrice Delabie, Alfred W. Prais, Randy Schaecher, Daniel Vulliet, Edouard Wales.
Application Number | 20080103438 11/664236 |
Document ID | / |
Family ID | 36072208 |
Filed Date | 2008-05-01 |
United States Patent
Application |
20080103438 |
Kind Code |
A1 |
Prais; Alfred W. ; et
al. |
May 1, 2008 |
Method For Reducing Or Eliminating Residue In A Glass Container And
A Glass Container Made In Accordance Therewith
Abstract
A method of preparing a glass medical container is provided
including the steps of providing a glass blank and forming a
channel through a part of the glass blank, the channel being
substantially free of tungsten or derivatives thereof. In a further
aspect of the subject invention, a glass medical container is
provided including a glass body having a channel extending through
a part of the glass body, the channel being substantially free of
tungsten or derivatives thereof. With the subject invention,
tungsten or derivatives thereof can be generally or altogether
completely avoided in glass medical containers.
Inventors: |
Prais; Alfred W.; (Hewitt,
NJ) ; Cocheteux; Bruno; (Voiron, FR) ; Cortes;
Arturo; (Estado de Mexico, MX) ; Delabie;
Patrice; (Montbonnot, FR) ; Wales; Edouard;
(Saint Martin D'Heres, FR) ; Dale Luedtke; Richard;
(Columbus, NE) ; Schaecher; Randy; (Columbus,
NE) ; Vulliet; Daniel; (Saint Pasil de Varces,
FR) |
Correspondence
Address: |
DAVID W. HIGHET VP & CHIEF IP COUNSEL;BECTON, DICKINSON AND COMPANY
(Hoffman & Baron), 1 BECTON DRIVE, MC 110
FRANKLIN LAKES
NJ
07417-1880
US
|
Family ID: |
36072208 |
Appl. No.: |
11/664236 |
Filed: |
September 30, 2005 |
PCT Filed: |
September 30, 2005 |
PCT NO: |
PCT/US05/35710 |
371 Date: |
December 28, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60614914 |
Sep 30, 2004 |
|
|
|
Current U.S.
Class: |
604/93.01 ;
65/102 |
Current CPC
Class: |
C03B 23/092 20130101;
A61M 5/3134 20130101; A61M 5/3129 20130101; A61M 5/34 20130101;
A61J 1/00 20130101 |
Class at
Publication: |
604/93.01 ;
65/102 |
International
Class: |
A61M 31/00 20060101
A61M031/00; C03B 23/02 20060101 C03B023/02 |
Claims
1. A method for preparing a glass medical container comprising the
steps of: providing a glass blank; and forming a channel through a
part of said glass blank, said channel being substantially free of
tungsten or derivatives thereof.
2. A method as in claim 1, wherein said forming step comprises
providing a pin at an opening in said glass blank and manipulating
a part of said glass blank about said pin to form said channel.
3. A method as in claim 2, comprising providing a pin of a material
which does not oxidize during said forming step.
4. A method as in claim 2, comprising providing a pin of a material
selected from the group consisting of metals or alloys containing
platinum or platinum group metals, metals or alloys containing
nickel, ceramics, silicides, and combinations thereof.
5. A method as in claim 2, wherein said pin does not contain
tungsten.
6. A method as in claim 1, wherein said forming step comprises
forming a channel that has a length and defines a diameter that is
substantially constant along said length.
7. A method as in claim 1, wherein said forming step comprises
forming a channel that has a length and defines a diameter that
varies along said length.
8. A method as in claim 7, wherein said forming step comprises
forming a channel that has a first portion defining a first
substantially constant diameter and a second portion defining a
second substantially constant diameter, said first diameter being
larger than said second diameter.
9. A method as in claim 1, wherein said forming step comprises
forming a channel through a part of said glass blank, said channel
having less than about 12 parts per billion of tungsten or
derivatives in said channel.
10. A method as in claim 1, wherein said glass medical container is
selected from the group consisting of a syringe barrel, vial, and
drug cartridge body.
11. A method as in claim 1, wherein the amount of tungsten or
derivatives thereof are determined before subsequent processing of
said glass blank.
12. A method as in claim 1, wherein said glass blank is unwashed
before or after said forming step.
13. A method as in claim 1, wherein said glass blank is
unsterilized before or after said forming step.
14. A method as in claim 1, wherein said forming step includes two
or more forming stages, each said forming stage including providing
a pin at an opening in said glass blank and manipulating a part of
said glass blank about said pin to form said channel.
15. A method as in claim 14, wherein each said pin is of a material
which does not oxidize during said forming step.
16. A method as in claim 14, wherein each said pin is of a material
selected from the group consisting of metals or alloys containing
platinum or platinum group metals, metals or alloys containing
nickel, ceramics, suicides, and combinations thereof.
17. A method as in claim 14, wherein each said pin does not contain
tungsten.
18. A glass medical container comprising a glass body defining a
reservoir for containing a substance and having a channel extending
through a part of said glass body and in fluid communication with
said reservoir, said channel defining an outlet of said container
and being substantially free of tungsten or derivatives
thereof.
19. A container as in claim 18, wherein said channel has a length
and defines a diameter that is substantially constant along said
length.
20. A container as in claim 18, wherein said channel has a length
and defines a diameter that varies along said length.
21. A container as in claim 20, wherein said channel has a first
portion defining a first substantially constant diameter and a
second portion defining a second substantially constant diameter,
said first diameter being larger than said second diameter.
22. A container as in claim 18, wherein the amount of tungsten or
derivatives in said channel is 12 parts per billion or less.
23. A container as in claim 18, wherein said glass medical
container is selected from the group consisting of a syringe
barrel, vial, and drug cartridge body.
24. A method of producing a glass medical container comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank; and forming said glass blank to conformingly
engage said pin to form a channel, wherein said pin is of a
material which does not oxidize during said forming of said glass
blank.
25. A method as in claim 24, wherein said forming step comprises
forming said glass blank to form a channel having a length and
defining a diameter that is substantially constant along said
length.
26. A method as in claim 24, wherein said forming step comprises
forming said glass blank to form a channel having a length and
defining a diameter that varies along said length.
27. A method as in claim 26, wherein said forming step comprises
forming said glass blank to form a channel having a first portion
defining a first substantially constant diameter and a second
portion defining a second substantially constant diameter, said
first diameter being larger than said second diameter.
28. A method as in claim 24, wherein said glass medical container
is selected from the group consisting of a syringe barrel, vial,
and drug cartridge body.
29. A method as in claim 24, wherein said forming step comprises
thermally manipulating said glass blank.
30. A method as in claim 24, wherein said forming step comprises
mechanically manipulating said glass blank.
31. A method as in claim 24, wherein said step of providing a pin
comprises providing a pin of a material is selected from the group
consisting of metals or alloys containing platinum or platinum
group metals, metals or alloys containing nickel, ceramics,
silicides, and combinations thereof.
32. A method as in claim 24, wherein said pin does not contain
tungsten.
33. A method as in claim 24, wherein said forming step comprises
forming a channel in said glass blank, said channel being
substantially free of tungsten or derivatives thereof.
34. A method as in claim 33, wherein the amount of tungsten or
derivatives thereof are determined before subsequent processing of
said glass blank.
35. A method as in claim 33, wherein said glass blank is unwashed
before or after said forming step.
36. A method as in claim 33, wherein said glass blank is
unsterilized before or after said forming step.
37. A glass medical container made in accordance with the method of
claim 1.
38. A glass medical container as in claim 37, wherein said
container is a syringe barrel.
39. A glass medical container made in accordance with the method of
claim 24.
40. A glass medical container as in claims 39, wherein said
container is a syringe barrel.
41. A method of producing a glass medical container comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank; introducing a gas near said pin; and forming said
glass blank to conformingly engage said pin to form a channel, said
channel being substantially free of tungsten or derivatives
thereof.
42. A method as in claim 41, wherein said forming step comprises
forming said glass blank to form a channel having a length and
defining a diameter that is substantially constant along said
length.
43. A method as in claim 41, wherein said forming step comprises
forming said glass blank to form a channel having a length and
defining a diameter that varies along said length.
44. A method as in claim 41, wherein said forming step comprises
forming said glass blank to form a channel having a first portion
defining a first substantially constant diameter and a second
portion defining a second substantially constant diameter, said
first diameter being larger than said second diameter.
45. A method as in claim 41, wherein said glass medical container
is selected from the group consisting of a syringe barrel, vial,
and drug cartridge body.
46. A method as in claim 41, wherein said forming step comprises
thermally manipulating said glass blank.
47. A method as in claim 41, wherein said forming step comprises
mechanically manipulating said glass blank.
48. A method as in claim 41, wherein the amount of tungsten or
derivatives thereof are determined before subsequent processing of
said glass blank.
49. A method as in claim 41, wherein said glass blank is unwashed
before or after said forming step.
50. A method as in claim 41, wherein said glass blank is
unsterilized before or after said forming step.
51. A glass medical container made in accordance with the method of
claim 41.
52. A glass medical container as in claim 51, wherein said
container is a syringe barrel.
53. A method of producing a glass syringe barrel comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank, said pin having a smaller diameter than said
opening; and, manipulating said glass blank transversely to
conformingly engage said pin to form a channel, wherein said pin is
of a material which does not oxidize during said forming of said
glass blank.
54. A method of producing a glass medical container comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank; and, forming said glass blank to conformingly
engage said pin to form a channel, wherein said pin is of a
material selected from the group consisting of metals or alloys
containing platinum or platinum group metals, metals or alloys
containing nickel, silicides, and combinations thereof.
55. A method of producing a syringe comprising the steps of:
providing a glass blank; providing a pin at an opening in said
glass blank; forming said glass blank to conformingly engage said
pin to form a channel, wherein said pin is of a material which does
not oxidize during said forming of said glass blank; and, fixing a
needle in said channel.
56. A method of producing a glass medical container comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank; and, forming said glass blank to conformingly
engage said pin to form a channel, said channel having a first
portion with a first diameter and a second portion with a diameter
smaller than said first diameter, wherein said pin is of a material
which does not oxidize during said forming of said glass blank.
57. A method as in claim 56, wherein said first diameter is about
0.6 mm and said second diameter is in the range of 0.2 to 0.4
mm.
58. A method of producing a glass medical container comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank; and, forming said glass blank to conformingly
engage said pin to form a channel, wherein said pin is of a
material which does not oxidize when exposed to temperatures in the
range of 600 C-900 C and elevated pressure during said forming of
said glass blank.
59. A method of producing a glass medical container comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank; and, forming said glass blank to conformingly
engage said pin to form a channel, wherein said pin is of a
platinum/rhodium alloy with 80%-90% platinum and 20%-10%
rhodium.
60. A method of producing a glass medical container comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank; and, forming said glass blank to conformingly
engage said pin to form a channel, wherein said pin is of a
material which does not oxidize during said forming of said glass
blank, and, wherein, without washing, said channel is substantially
free of tungsten or derivatives thereof.
61. A method of producing a glass medical container comprising the
steps of: providing a glass blank; providing a pin at an opening in
said glass blank; and, forming said glass blank to conformingly
engage said pin to form a channel, wherein said pin is of a
material which does not oxidize during said forming of said glass
blank, and, wherein, without washing, the amount of tungsten in
said channel is 12 parts per billion or less.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a National Stage Application under 35
U.S.C. .sctn.371 of PCT International Application No.
PCT/US2005/035710, filed Sep. 30, 2005, which claims priority to
U.S. Provisional Application No. 60/614,914, filed Sep. 30, 2004,
the entire disclosures of which are incorporated by reference
herein.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a method for reducing tungsten and
derivatives thereof in a glass container and to a glass container
with reduced tungsten and derivatives thereof.
[0003] Tungsten and derivatives thereof have been commonly used in
glass forming techniques. In particular, tungsten-containing pins
have been used in forming shaped apertures or channels in glass
structures. As used herein, the term "tungsten-containing" means
tungsten, tungsten plus one or more other materials, or one or more
other materials plus tungsten, in any combination and percentage.
Tungsten has a high fusion temperature relative to glass and is
well suited for glass manufacturing. Typically, a
tungsten-containing pin is used to form an aperture or channel in a
glass container, with the glass being thermally and/or mechanically
manipulated about the pin and into conforming engagement therewith.
An iterative process can be used where a plurality of pins are used
sequentially to gradually form the aperture or channel in a
sequence of manipulations to the glass. With removal of the final
pin, a finished aperture or channel is left in the glass structure.
This technique has been commonly used in the formation of glass
medical containers, including glass syringe barrels, glass vials,
and glass drug cartridge bodies. Each of the glass medical
containers (glass syringe barrels, glass vials and glass drug
cartridge bodies) includes a reservoir for containing a drug, and a
channel in communication with the reservoir to provide a means of
accessing or removing the drug from the reservoir, typically via a
cannula or similar liquid communication means.
[0004] It has been found that tungsten-containing pins undesirably
leave a tungsten-containing residue on the formed glass structures,
particularly, portions that had been in contact with the pins, for
example, the aperture or channel. The tungsten-containing residue
may have detrimental effects on any substance contained or stored
within the glass medical container. First, tungsten or derivatives
thereof may be deposited as particulate matter on an inner surface
of the aperture or channel, and such particulate matter may be
visible in the contained substance. Certain medical procedures
require a medical practitioner to view the procedure under
magnification, including the administration of a drug from a glass
medical container. The presence of such particulate matter may be
dangerous to the patient and may also be disconcerting to the
medical practitioner. Second, drugs containing proteins may be
adversely affected by exposure to the tungsten or derivatives
thereof. Certain proteins are prone to clump or aggregate about
tungsten or derivatives thereof. This clumping or aggregation may
lead to a loss in efficacy or other undesirable effects of the
drug. In addition, in certain situations, the clumping or
aggregation may be so extreme that solid fragments may be seen by
the naked eye and be disconcerting to a potential user.
[0005] Water washing glass medical containers is known in the prior
art. Such washing techniques have been known to reduce or remove
tungsten-containing residue. However, washing techniques have
inherent limitations and cannot reliably and repeatedly remove all
or substantially all tungsten and derivatives thereof from a glass
medical container.
SUMMARY OF THE INVENTION
[0006] In one aspect of the subject invention, a method for
preparing a glass medical container is provided including the steps
of providing a glass blank and forming a channel through a part of
the glass blank, the channel being substantially free of tungsten
or derivatives thereof. In a further aspect of the subject
invention, a glass medical container is provided including a glass
body having a channel extending through a part of the glass body,
the channel being substantially free of tungsten or derivatives
thereof. With the subject invention, tungsten or derivatives
thereof can be generally or altogether completely avoided in glass
medical containers.
[0007] As used herein, a "drug" is an illustrative and non-limiting
term and refers to any substance to be injected into a patient for
any purpose; "tungsten or derivatives thereof" shall mean tungsten
or any substance containing tungsten, including, but not limited
to, tungsten salts and tungsten-containing alloys; and,
"substantially free" shall mean a level of tungsten or derivatives
thereof low enough to not detrimentally alter or affect a drug. For
example, and by way of illustration and not limitation,
substantially free may mean tungsten or derivatives thereof at a
level that the tungsten or derivatives thereof is not visible, does
not detrimentally alter the efficacy or otherwise adversely effect
the drug, and/or does not detrimentally promote unacceptable levels
of clumping or aggregation of proteins contained in the drug.
[0008] These and other features of the invention will be better
understood through a study of the following detailed description
and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a plan view of an exemplary glass medical
container in accordance with the subject invention;
[0010] FIG. 2 is a schematic showing formation of a channel in a
glass medical container; and
[0011] FIG. 3 is a partial cross-sectional view of an alternative
channel shape formed in a glass medical container.
DETAILED DESCRIPTION OF THE INVENTION
[0012] With the subject invention, a method is provided for
substantially reducing or altogether eliminating tungsten or
derivatives thereof from a glass container without the need for
additional annealing, sterilization or washing steps after the
container has been completely formed. The method is particularly
well-suited for use in forming glass medical containers. For
illustrative purposes, an exemplary glass medical container 10 is
shown and described which is in the form of a glass syringe barrel.
As can be appreciated by those skilled in the art and from the
disclosure provided herein, the glass medical container 10 can be
any glass body used for containing or storing a liquid and/or dry
substance, including, but not limited to glass syringe barrels,
glass vials, and glass drug cartridge bodies.
[0013] With reference to FIG. 1, the glass medical container 10
defines a reservoir 12 and has a hub 8 with a channel 14 defined
therethrough and in communication with the reservoir 12. The glass
medical container 10 is preferably a unitary glass body. The
channel 14 forms an aperture 16 at a distal end of the glass
medical container 10. The channel 14, via the aperture 16, provides
access to the reservoir 12 and any drug which may be contained
therein. With the glass medical container 10 being a glass syringe
barrel, the channel 14 is formed through the hub 8. The reservoir
12, as formed in the glass medical container 10, may partly define
a volume for containing a drug. A piston, plunger, septum, tip cap,
stopper, and so forth, may be used in connection with the glass
medical container 10 to form a closed volume for containing a drug
within the reservoir 12.
[0014] With reference to FIG. 2, a process in accordance with the
subject invention is depicted for forming the channel 14. In
particular, a pin 20 is provided to form and extend into and
possibly through an opening 22 defined in a glass blank 24. The
glass blank 24 is a partially formed version of the glass medical
container 10. For example, a glass blank 24 may comprise a
generally cylindrical part having a substantially constant outer
diameter, or it may be a partially or completely formed part having
a portion through which the channel 14 is formed and defined.
Thermal and mechanical manipulations are performed on and to the
glass blank 24 to form the final glass medical container 10 as is
known in the art. The opening 22 is in communication with reservoir
26 which ultimately, after full formation, results in the reservoir
12.
[0015] To form the channel 14, portions of the glass blank 24 about
the opening 22 are manipulated, either in one process or in
iterations, to force the portions of the glass blank 24 into
conforming engagement with the pin 20. The manipulations may
include mechanical manipulations (e.g., rolling or other shape
forming processes) and/or thermal manipulations (e.g., heating
glass to a malleable state). In this manner, the channel 14 is
generally formed with a cross-sectional shape corresponding to the
exterior surface of the pin 20. For example, as shown in FIG. 2,
the pin 20 is shown with a constant cross-section along its length.
Correspondingly, as shown in FIG. 1, the channel 14 also has a
constant cross-section along its length. Alternative configurations
for the channel 14 are possible. With reference to FIG. 3, the
channel 14 is shown with varying cross-sections along its length.
This configuration is preferred for staked needle configuration
glass syringe barrels, while the constant cross-sectional
configuration of FIG. 1 is preferred for Luer tip mounted needle
configurations. With the configuration of FIG. 3, a first portion
21 of the channel 14 defines a substantially constant diameter D1,
while a second portion 23 of the channel 14, located closer to the
reservoir 12, defines a substantially constant diameter D2. The
diameter D1 is larger than the diameter D2 with a step 25 being
formed therebetween. The step 25 acts as a stop against an
insertion of a needle during assembly. The needle is glued or
otherwise secured within the first portion 21 and in communication
with the second portion 23. The channel 14 can take on various
configurations (e.g., more than two diameter changes, tapering,
etc.), and, as is readily recognized, the pin 20 is shaped
externally to achieve the desired configuration of the channel 14.
Alternatively, a variety of the pins 20 having different diameters
may be used to form a channel 14 as shown in FIG. 3, e.g.,
sequentially.
[0016] For typical applications where the glass medical container
10 is a glass syringe barrel, the channel 14 may have a
configuration as in FIG. 1 with a continuous diameter of about 1.0
mm; or, the channel 14 may a configuration as in FIG. 3 with a
diameter D1 of about 0.6 mm, and a diameter D2 in the range of 0.2
to 0.4 mm. Also, the channel 14, as is common with glass syringe
barrels, defines a diameter smaller than the internal diameter
defined by the reservoir 12. With a vial configuration or a drug
cartridge body configuration, the channel 14 may have a diameter
generally equal to the internal diameter of the reservoir 12, or
even greater than the internal diameter of the reservoir 12.
[0017] For the avoidance of tungsten or derivatives thereof in the
channel 14, it is preferred that the pin 20 be formed of a material
that will not oxidize during the glass forming process described
above. Generally, all materials can be oxidized, although special
circumstances may be required for oxidation. With the glass forming
process discussed above in connection with FIG. 2, the pin 20 may
be thermally manipulated by exposure during thermal manipulation of
the glass blank 24 to temperatures in the range of 600.degree.
C.-900.degree. C., and may be subjected to elevated pressures
generated by shape-forming tools during mechanical manipulation of
the glass blank 24. Under these conditions, tungsten oxidizes.
Oxidation of prior art pins led to deposition of tungsten or
derivatives thereof on portions of the glass blank 24 that were in
contact with the pins, particularly the channel 14. In addition,
the pin 20 is typically used in large scale, repetitious
manufacturing and subjected to fast thermal cycles of heat
application and removal, resulting in fatigue to the surface of the
pin 20 and consequently, to the pin 20. Surface fatigue leads to
weakening of the structure of the pin 20 and mechanical failure
with fragments (typically microscopic) thereof breaking off during
use of the pin 20 in the glass forming process and, consequently,
to deposition of tungsten or derivatives thereof on and within the
channel 14.
[0018] As indicated above, it is preferred that the pin 20 be
formed of a material which does not oxidize when subjected to a
glass forming process which is may be typically conducted under
temperatures in the range of 600.degree. C.-900.degree. C. and
under elevated pressure caused by shape-forming tools. These
conditions hereinafter shall be referred to as "glass forming
process conditions." It will be obvious to persons skilled in the
art that other conditions and parameters may be present during the
process of forming a glass blank into a glass medical container. By
way of non-limiting examples, materials that will not oxidize under
the glass forming process conditions, and useable for the pin 20 in
accordance with the present invention, include, but are not limited
to, the following: metals or alloys containing platinum or platinum
group metals; metals or alloys containing nickel; ceramics;
silicides; and combinations thereof. It is preferred that the pin
20 be formed of a platinum/rhodium alloy with 80%-90% platinum and
20%-10% rhodium. With the pin 20 being formed of one of the
aforementioned materials, or other material(s) that will not
oxidize under the glass forming process conditions, deposition of
tungsten or derivatives thereof on the glass medical container 10
due to the oxidation process can be avoided. As a result, the
channel 14 can be formed substantially free of tungsten or
derivatives thereof. It is also preferred that the pin 20 have a
melting temperature above the melting temperature of the associated
glass being formed into the glass medical container 10.
[0019] An alloy containing tungsten may be used to form the pin 20
where the tungsten-containing alloy does not oxidize under the
glass forming process conditions. For example, the pin 20 may be
formed of with a tungsten carbide which does not oxidize under the
glass forming process conditions. To further minimize the amount of
tungsten or derivatives thereof deposited in the channel 14 in
accordance with this embodiment, it is preferred that the pin 20 be
formed of a material containing a minimal amount of tungsten, even
no tungsten.
[0020] In addition to selection of the material from which the pin
20 is made, the present invention may also control the environment
in which the pin 20 is forming the channel 14 by introducing a
controlling gas in the area of the pin 20 and channel 14. For
example, the introduction of an inert gas such as nitrogen gas, by
way of non-limiting example, in and around the area in which the
pin 20 is used to reduce the oxygen content in that area can reduce
oxidation of the pin 20.
[0021] As will be appreciated by those skilled in the art, the
formation of the channel 14 may require various sequential forming
steps including multiple pins 20, such as pins 20 of constant or
varying diameters. For example, the channel 14 may be iteratively
formed smaller over a sequence of forming stages with increasingly
smaller diameter pins 20 being used. In each forming stage, the
channel 14 is brought into conforming engagement with the
associated pin 20, until a final forming stage is reached. All of
the pins 20 used in the various stages in the formation of the
channel 14 may be formed of the preferred materials described
above. Alternatively, it has been found that certain forming stages
may cause greater deposition of tungsten or derivatives thereof
than other forming stages. For these critical forming stages, it is
preferred that the pins 20 be formed of materials which do not
oxidize under the glass forming process conditions and which do not
include tungsten. The less critical forming stages may use pins
formed of any material, including tungsten. With the glass medical
container 10 being a glass syringe barrel and being subjected to
multiple forming stages using a multiple of the pins 20, it is
preferred that the last forming step utilize the pin 20 being
formed of materials which do not oxidize under the glass forming
process conditions and which do not include tungsten. The preceding
forming stages may be formed of any material suitable for pin
formation. The less critical forming stages may not expose the pin
20 to the same amounts of thermal and/or mechanical manipulation
because the channel 14 is only roughly formed and thus may not
contact the pin 20 to the same extent as may occur during the final
forming stage(s).
[0022] With the subject invention, the channel 14 can
advantageously be formed substantially free of tungsten or
derivatives thereof. Using the following procedure for measuring
concentration, it is preferred that the channel 14 have tungsten or
derivatives thereof in an amount of 12 parts per billion or less.
With the preferred process, not only is oxidation of the pin 20
avoided, but the pin 20 may be formed to not deposit tungsten or
derivates thereof even under mechanical failure. This preferred
process may produce glass medical containers which have
undetectable levels of tungsten or derivatives thereof. These
concentration levels are obtainable with the subject invention on
large scale, industrial processes within highly acceptable
tolerance levels. Prior art washing techniques have not been
capable of obtaining such low levels on a repeated, wide-spread
consistent basis.
[0023] Significantly, the subject invention is able to produce a
glass medical container 10 that is substantially free tungsten or
derivatives thereof without the need for additional annealing,
sterilization or washing steps. With reference to FIG. 2, the glass
blank 24 is an intermediate product that is both unsterilized and
unwashed. Upon full formation, the glass medical container 10 may
be subjected to annealing, sterilizing and air or liquid washing,
although such further processing is not always carried out (such
unsterilized containers being referred to as "bulk" processed
containers). The sterilizing and washing steps may provide for
additional removal of any residual tungsten or derivatives thereof
which may be present. This residual tungsten or derivatives thereof
may have come from the glass raw material, tooling which contacts
the glass during formation, or tungsten pins used in the process.
The aforementioned levels of tungsten or derivatives thereof,
however, are achieved in accordance with the present invention
without the additional annealing, sterilizing or washing
processes.
[0024] Levels of tungsten or derivatives thereof may be measured by
any technique. Different techniques may provide different results
depending on how aggressively the tungsten or derivatives thereof
is removed from the glass medical container for testing (i.e., more
aggressive techniques remove higher levels of tungsten residue).
With reference to Wang, et al., Journal of Pharmaceutical and
Biomedical Analysis, 19 (1999) 937-943, "Determination of Tungsten
in Bulk Drug Substance and Intermediates by ICP-AES and ICP-MS", a
method of measuring levels of tungsten in drugs is described.
Similar methodology can be used for measuring tungsten-containing
residue levels. The inventors herein relied on the following
procedure to measure the aforementioned levels of tungsten or
derivatives thereof: [0025] 1. filling a glass medical container
with purified water (e.g., prepared by laboratory purification
system, Millipore Milli Ro 4) and sealing the glass medical
container (e.g., with a tip cap); [0026] 2. placing the filled
glass medical container into an ultrasonic bath containing water at
ambient temperature for 60 minutes; [0027] 3. removing the glass
medical container and dispensing the contained solution into a
sample vessel; and, [0028] 4. measuring the concentration of the
tungsten in the solution by Inductively Coupled Plasma Mass
Spectrometry (ICP/MS).
[0029] The aforementioned levels of tungsten or derivatives thereof
are actually measured concentration levels of tungsten in the
extracted solution.
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