U.S. patent application number 12/960715 was filed with the patent office on 2011-06-09 for sealing of plastic containers.
This patent application is currently assigned to BREATH LIMITED. Invention is credited to Ian Gardner Cameron McAffer, Peter Ernest Tasko.
Application Number | 20110131929 12/960715 |
Document ID | / |
Family ID | 39871050 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110131929 |
Kind Code |
A1 |
McAffer; Ian Gardner Cameron ;
et al. |
June 9, 2011 |
Sealing of Plastic Containers
Abstract
An ampoule contains a solution, e.g. an inhalation or injectable
pharmaceutical, and an outer surface of the ampoule is coated with
a metal or metal compound so as to reduce moisture egress from the
ampoule and reduce contamination of ampoule contents from external
sources. Labels are easily applied to the coating.
Inventors: |
McAffer; Ian Gardner Cameron;
(Kent, GB) ; Tasko; Peter Ernest; (Herts,
GB) |
Assignee: |
BREATH LIMITED
Kent
GB
|
Family ID: |
39871050 |
Appl. No.: |
12/960715 |
Filed: |
December 6, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11196349 |
Aug 4, 2005 |
|
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12960715 |
|
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Current U.S.
Class: |
53/467 |
Current CPC
Class: |
Y10T 428/1352 20150115;
B65D 1/09 20130101; Y10T 428/13 20150115; B65D 25/34 20130101; A61M
15/009 20130101; Y10T 428/131 20150115; A61M 15/0065 20130101 |
Class at
Publication: |
53/467 |
International
Class: |
B65B 1/04 20060101
B65B001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 9, 2005 |
GB |
GB0502666.1 |
May 5, 2005 |
GB |
GB0509210.1 |
Claims
1-26. (canceled)
27. A method of making an ampoule, comprising: (i) forming the
ampoule by a blow-fill-seal process; (ii) filling the ampoule
during said blow-fill-seal process with from 0.5 ml to 10 ml of (a)
an inhalation pharmaceutical in a pharmaceutically acceptable
carrier, or (b) an injection pharmaceutical in a pharmaceutically
acceptable carrier; (iii) sealing the filled ampoule during said
blow-fill-seal process; and (iv) applying via arc deposition a
coating of a metal to at least 70% of the outer surface of the
ampoule.
28. The method of claim 27, comprising applying the coating to at
least 90% of the outer surface of the ampoule.
29. The method of claim 27, comprising applying the coating to at
least 95% of the outer surface of the ampoule.
30. The method of claim 27, comprising applying the coating to
substantially all of the outer surface of the ampoule.
31. The method of claim 27, wherein the metal is selected from
aluminum, titanium, and chromium.
32. The method of claim 27, wherein the coating has a thickness of
up to 50 microns.
33. The method of claim 27, wherein the coating has a thickness of
up to 25 microns.
34. The method of claim 27, wherein the coating has a thickness of
up to 10 microns.
35. The method of claim 27, comprising applying the coating via
filtered cathode arc deposition.
36. A method of making an ampoule, comprising: (i) forming the
ampoule by a blow-fill-seal process; (ii) filling the ampoule
during said blow-fill-seal process with from 0.5 ml to 10 ml of (a)
an inhalation pharmaceutical in a pharmaceutically acceptable
carrier, or (b) an injection pharmaceutical in a pharmaceutically
acceptable carrier; (iii) sealing the filled ampoule during said
blow-fill-seal process; and (iv) applying via arc deposition a
coating of tetrahedral amorphous carbon to at least 70% of the
outer surface of the ampoule.
37. The method of claim 36, comprising applying the coating to at
least 90% of the outer surface of the ampoule.
38. The method of claim 36, comprising applying the coating to at
least 95% of the outer surface of the ampoule.
39. The method of claim 36, comprising applying the coating to
substantially all of the outer surface of the ampoule.
40. The method of claim 36, wherein the coating has a thickness of
up to 50 microns.
41. The method of claim 36 wherein the coating has a thickness of
up to 25 microns.
42. The method of claim 36, wherein the coating has a thickness of
up to 10 microns.
43. The method of claim 36, comprising applying the coating via
filtered cathode arc deposition.
44. A method of sealing a container, wherein the container contains
a solution of an inhalation pharmaceutical or an injection
pharmaceutical in a pharmaceutically acceptable carrier and wherein
the container is made of polymer consisting essentially of
polyethylene or polypropylene, comprising applying to an outer
surface of the container a coating comprising a metal or a metal
compound.
45. The method of claim 44, wherein the metal is selected from
aluminum, titanium, chromium and tetrahedral amorphous carbon.
46. The method of claim 44, wherein the container is an
ampoule.
47. The method of claim 46, comprising forming the ampoule by a
blow-fill-seal process.
48. The method of claim 44, comprising applying the coating over at
least 90% of the outer surface of the container.
49. The method of claim 44, comprising applying the coating by
physical vapor deposition or arc deposition.
50. The method of claim 44, wherein the coating has a thickness of
up to 50 microns.
51. The method of claim 44, wherein the coating has a thickness of
up to 25 microns.
52. The method of claim 44, wherein the coating has a thickness of
up to 10 microns.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the sealing of containers,
to the coating of containers made of plastics material used for
pharmaceutical formulations, and in particular to coating ampoules
to achieve a sealing effect. The invention relates also to the
sealed or coated containers, in particular coated ampoules.
BACKGROUND TO THE INVENTION
[0002] Pharmaceutical and cosmetic formulations are presented in a
variety of different packaging, including packaging made of glass,
metal, plastic and natural materials. For liquid formulations, e.g.
solutions or suspensions, the packaging must be and remain sealed
to prevent leakage. However, a number of technical and practical
difficulties exist with all such containers.
[0003] Some formulations may contain highly volatile substances or
other relatively small molecules that can diffuse out through the
material of the container. This is a particular problem with, say,
perfumes. Shelf-life is thus limited as products may lose potency,
aroma or flavour. As result, containers for such products are made
of material that is impermeable e.g. glass, such materials being
generally rather expensive. It is hence not possible to use cheaper
materials such as plastics so high packaging costs are
incurred.
[0004] Pharmaceutical formulations in containers may have to be
sterilized under conditions of high temperature or pressure, or
once filled under sterile conditions must be robust enough to
maintain that sterility. Again, this tends towards higher
production costs.
[0005] It is known to administer drugs to the lungs of a patient
using a nebulizer, allowing a patient to administer the drug whilst
breathing normally. The drugs are provided in a unit dose ampoule
(UDA), containing a relatively small volume, typically 1 mL-5 mL,
of solution and typically made of plastics material. A method of
making ampoules is by Blow-Fill-Seal (BFS), under aseptic
conditions, in which the ampoule is formed by extrusion and filled
with solution in a multi-part but essentially one-step process. If
necessary, and provided the contents are not heat labile, heat
sterilization can be used, e.g. ampoules can be sterilised by
terminal sterilisation methods, i.e. after the ampoule has been
filled and sealed. These methods are well established and accepted
by regulatory authorities worldwide.
[0006] A known problem with existing ampoules is that they allow
oxygen, other gases and other volatile compounds into the ampoule
and allow water (moisture) to exit. Testing of the contents has
revealed that, during storage, contaminants can pass through the
plastic of ampoule walls and be absorbed into the formulation. As
one specific example, unacceptable amounts of vanillin have been
found inside ampoules, leading to failure of the product and
refusal of regulatory authorities to licence the ampoules without
safeguards against this external contamination.
[0007] The US FDA has recently required that ampoules be
over-wrapped by a sealing pouch to avoid contamination of the
ampoule contents. The pouch material is typically a tri-laminate of
paper and/or polymer, aluminum and low density polyethylene (LDP).
This pouch is regarded as an acceptable solution to the
problem.
[0008] Ampoules are typically produced in strips of multiples of
single units doses, e.g. fives, tens, thirties etc. Therefore, a
problem with pouches is that if several ampoules are contained
within one pouch then as soon as the pouch is opened and the first
ampoule used, the remaining ampoules are exposed to the environment
and can be contaminated.
[0009] The permeability of the LDP also restricts the labeling of
the ampoules, as inks used for direct printing onto ampoules and
adhesives used to attach paper labels must be checked carefully to
ensure none will penetrate the ampoule and contaminate the
contents.
[0010] Some ampoules are topped up with inert gas, e.g. nitrogen.
Even in a pouch there is some equilibration of nitrogen with the
gases outside the ampoule but inside the pouch. As soon as the
pouch is opened more nitrogen will be lost from the ampoule.
[0011] LDP ampoules are translucent and some photo-sensitive
materials when stored in these might be damaged after long-term
storage and exposure to light. Pouches offer a partial solution
but, again, once the pouch is opened ampoules inside are exposed to
light for indefinite periods before being used.
[0012] Separately, LDP tubes are fairly commonly used for
cosmetics. But it is necessary to avoid oxygen getting into certain
tube contents, e.g. if there are liposomes or other oxygen
sensitive contents. LDP and other such materials are as a result
not generally acceptable for manufacture of tubes for these
cosmetics.
[0013] An object of the present invention is to solve or at least
ameliorate the above-identified issues. An object of preferred
embodiments of the invention is to provide alternative, more
preferably improved methods of sealing of containers, and
containers, in particular ampoules sealed by the methods.
SUMMARY OF THE INVENTION
[0014] The invention is based upon use of a metal-containing
sealing layer to provide a coating on containers made of plastics
material.
[0015] In a first aspect, the invention provides an ampoule,
comprising a coating of a metal or a metal compound.
[0016] Generally, the invention provides a container for containing
liquids, made of plastics material and comprising a coating of
metal or a metal compound.
[0017] In a second aspect, the invention provides a method of
reducing moisture egress from a container made of plastics
material, comprising applying to an outer surface of the container
a coating comprising a metal or a metal compound.
[0018] In a third aspect, the invention provides a method of
sealing a container made of plastics material, comprising applying
to an outer surface of the container a coating comprising a metal
or a metal compound.
[0019] A fourth aspect of the invention provides a method of
applying a label to an ampoule, comprising applying a coating of a
metal or a metal compound to the ampoule and applying the label to
the coating.
[0020] The coating can be applied by first providing the plastics
layer and then applying the coating onto the layer or by producing,
for example by extrusion or otherwise, a plastics layer coated with
the metal coating.
DETAILED DESCRIPTION OF THE INVENTION
[0021] A coated container of the invention is an ampoule having a
coating of a metal or a metal compound. In use this coating is
found to have the effect of sealing the contents of the ampoule,
reducing loss of ampoule contents to the outside and reducing
contamination of the contents from the outside.
[0022] The ampoule is typically of plastics material, especially
polypropylene or polyethylene, low or high density or other polymer
used in manufacture of ampoules or in the drinks industry, e.g.
polyethylene terephthalate. Further, the ampoule will typically
contain a pharmaceutical agent, such as an inhalation drug or
injectable drug, in combination with a pharmaceutically acceptable
carrier.
[0023] The sealing is not required to be complete but is preferred
to be such that after testing for the periods required e.g. in the
case of ampoules to satisfy the regulatory authorities that the
contents are adequately protected so that no further steps such as
provision of external overwrapping by pouches are imposed. The
coating may hence cover at least 50% of the outer surface area of
the ampoule, or at least 70%, 80%, 90% or 95% of the outer surface
area of the ampoule. Very preferably substantially all of the
outside of the ampoule is coated.
[0024] When a strip of ampoules is coated and one ampoule detached
from the strip there may as a result be a side edge or portion of
the remaining end ampoule which is uncoated and thus exposed, but
this is likely to detract only slightly if at all from the overall
sealing effect of the coating--the exposed portion being small
compared to the total surface area and occurring at a position
where the thickness of the plastic, the junction between adjacent
ampoules, is generally greatest. The invention is thus useful for
coating single containers or ampoules and also ampoules designed to
be produced in strips and detached one-by-one.
[0025] The coating material can be selected from a wide variety of
metals and metal compounds which can be coated onto e.g. the
ampoule. The coating can comprise aluminium, copper, carbon,
chromium, silver, zirconium, tantalum, tungsten, titanium, cobalt,
gold, palladium, platinum, and their alloys, including steel, and
their compounds, including compounds of metals with gases, for
example carbon nitride, tin oxide, indium oxide, silicon dioxide.
Some of these coating materials are more expensive than others and
for containers such as ampoules made in large numbers and being
essentially for once-only use the coating preferably comprises
aluminium, titanium, chromium, silver, copper, or a mixture or
alloy of the aforesaid. Particularly preferred coatings comprise or
consist of aluminium, titanium, chromium or tetrahedral amorphous
carbon.
[0026] To apply the coating, a number of different techniques may
be employed. Suitable coating methods include physical vapour
deposition, e.g. by sputtering, and arc deposition. Sputter
coatings optionally have a UV lacquer to protect the coating and
improve adhesion.
[0027] Sputtering deposition, as an example of physical vapour
deposition, is performed in a vacuum chamber where atoms, generally
argon atoms, are ionized and accelerated to strike a target
material, say aluminium. Coating material enters the vapour phase
through a physical process rather than by a chemical or thermal
process. The argon atoms dislodge aluminium atoms when they strike
the target, then these ejected aluminium atoms strike the container
to be coated, and this process applies a dense coating. Argon (Ar)
ions can be created in an ion gun which then imparts kinetic energy
and directs the ions toward the target to be sputtered, or in a
plasma that contains Ar+ and electrons. The plasma glows because of
reactions between the electrons and atoms and ions and is neutral
in charge. The spectral content of the glow is indicative of the
ion species present and can be used to control the composition of
the deposited film. The interactions between electrodes and ionized
species and electrons are complicated, and the variety of
sputtering configurations existent emphasize specific aspects of
the plasma physics that is involved. For example, in magnetron
sputtering powerful permanent magnets behind the target contain
electrons in their fields to increase the probability of collisions
with atoms and metastable species and thereby increase the density
of available ions. In all forms of plasma sputtering, a virtual
electrode is created at the boundary between the plasma and a
volume known as the Crook's dark space, where electronic and ionic
interactions are absent. Ar+ ions are extracted from the plasma and
accelerated across the dark space to impinge on the target. During
the momentum transfer at the target surface, positive and negative
ions and electrons as well as atoms, dimers, and trimers are
released. The positive ions return to the target where they
contribute to heating. In some arrangements, negative ions and
electrons can strike the substrate located near the anode.
[0028] Sputter rate is determined by target voltage and current
density, as well as chamber pressure. High voltage and current
(power) releases more sputtered species; high pressure provides
more ion density but simultaneously reduces the energies of the
ions and atoms by scatter. Each sputter process must be optimized
for the materials used. It is generally held that sputtered films
adhere better than evaporated films. The variety of materials from
which sputtering targets can be made is nearly limitless. For
example, alloys of materials having different evaporation pressures
can be sputtered but not evaporated. Targets of single-element
materials, such as metals, are generally the pure metal, while
mixtures and doped composition targets are made by powder
metallurgy. Powder mixtures are hot-pressed under appropriate
atmosphere composition and may be sintered. Non-metal targets are
made by ceramic technology. Multi-element (or compound) mixtures
can be specially made.
[0029] Chemical vapour deposition or CVD is a generic name for a
group of processes that involve depositing a solid material from a
gaseous phase and is similar in some respects to physical vapour
deposition (PVD). PVD differs in that the precursors are solid,
with the material to be deposited being vaporised from a solid
target and deposited onto the substrate. Whilst CVD may in some
instances be suitable for the invention, generally the high
temperatures required restrict the material that can be coated. CVD
may also be too costly for large-scale, manufacture of one-use
products such as ampoules.
[0030] In arc deposition methods, an ion-containing plasma is
created in a vacuum between an anode and a target, usually the
cathode. In a filtered cathode arc, ions from the plasma are
steered towards the substrate via a filter designed to remove
neutral particles such as macroparticles. The ions deposit on the
surface, forming the coating. The filtered vacuum cathode arc can
apply coatings at lower temperatures, even lower than sputter
coaters, below 70 degrees C. and down to room temperatures, and is
hence particularly suitable for temperature sensitive substrates
such as plastics. Though, plastics which can withstand temperatures
up to around 120 degrees C. can be coated using sputter techniques.
Metal or carbon or alloy coatings can be made using the filtered
cathode arc, also compounds using introduction of reactive gas into
the coating chamber near the substrate.
[0031] Examples of background reading on thin film technology
including physical vapour deposition and vacuum arc deposition can
be found in John A. Thornton and D. W. Hoffman, Thin Solid Films,
171, 5 (1989); J. Vossen and W. Kern, eds., Thin Film Processes,
Academic Press, N.Y., 1978 and Handbook of Vacuum Arc Science and
Technology by: Boxman, R. L.; Sanders, D.; Martin, P. J..COPYRGT.
1995 William Andrew Publishing/Noyes. Sputter apparatus is
available from a number of commercial sources, including CPFilms
Inc. of Martinsville, USA. FCVA Apparatus is also available from a
number of commercial sources, including Nanofilm Technologies
International Pte. Ltd of Singapore. Filtered cathode vacuum arc
technology is described further in U.S. Pat. Nos. 6,761,805,
6,736,949, 6,413,387 and 6,031,239, the contents of which are
incorporated herein by reference. For the present invention, it is
preferred that the coating is applied by physical vapour deposition
or arc deposition.
[0032] Prior to coating of articles it is often preferred to carry
out cleaning or other preparation of the surface, to remove
contaminants and improve the adherence of the coating. For the
containers of the invention aqueous cleaning is generally
sufficient and can be omitted. For embodiments of the invention in
which the articles to be coated is made of or comprises polymer
such articles can be cleaned using known procedures except that
more careful handling may be required. In addition, during aqueous
cleaning polymers may absorb water which must later be removed to
achieve vacuum coating adhesion. The coating may adhere without any
treatment in which case even aqueous washing can be omitted.
[0033] The articles will likely remain clean for only a short
period unless in a special environment, such as a dry
nitrogen-purged container or in a UV/ozone chamber. One option is
to provide a cleaning and/or surface preparation station as part or
in juxtaposition to the coating station. A further consideration is
that newly formed or moulded polymer, as in the blow-fill-seal
process used for ampoule formation may not require any surface
preparation for adequate adhesion of the coating to be
obtained.
[0034] In use of the invention, ampoules can be prepared by forming
the ampoule and applying the coating to the ampoule. A known method
of forming ampoules is by blow-fill-seal (BFS), and the coating
step can conveniently be added to the ampoule production line
immediately after the BFS step and prior to packaging and/or
labeling. The ampoules typically contain from about 1 mL to about 5
mL (extractable volume) of solution.
[0035] The coating is designed to achieve sealing of the
containers, as described above. A suitable depth is of at least 20
nm, preferably at least 50 nm, and also suitably up to 50 microns,
preferably up to 20 microns. The coating depth may also be at least
100 nm and up to 10 microns.
[0036] In a specific embodiment of the invention, an ampoule is
made of plastics material and comprises a coating of aluminium
applied by sputter coating. More specifically, the ampoule contains
a solution of an inhalation pharmaceutical in a pharmaceutically
acceptable carrier. Thus, in an example of the invention in use,
blow-fill-seal technology is used to obtain ampoules containing 2
ml of a formulation containing levalbuterol and ipratropium in
saline. The ampoules are made from LDP and exit the filling
apparatus in strips of 10. The strips are coated with an external
coating of aluminium, applied using a sputter coater, to a depth of
approximately 300 nm, giving a shiny metallic look. The ampoules
are packaged in the usual way though not overwrapped. Patients are
given the ampoules in strips and tear off one ampoule at a time.
The remaining ampoules are kept in a (now reduced size) strip until
the next ampoule is removed and used, and so on until all ampoules
are used.
[0037] In further embodiments of the invention, an ampoule is made
of plastics material, comprises a coating of aluminium, chromium or
titanium applied by sputter coating or filtered cathode arc and
contains a solution of an injectable pharmaceutical in a
pharmaceutically acceptable carrier. The solution may for example
be water for injection or saline for injection. Typical volumes are
30 ml or less, 25 ml or less, 20 ml or less, 15 ml or less or 10 ml
or less. The ampoules can be manufactured in strips of 5, 10, 15 or
more, as for other embodiments of the invention, to be torn off and
used when required.
[0038] In a further specific embodiment of the invention, a plastic
ampoule is coated with a layer of titanium, applied by sputter
coating, to a depth of about 150 nm.
[0039] In a further specific embodiment of the invention, a plastic
ampoule is coated with tetrahedral amorphous carbon to a depth of
about 100 nm.
[0040] Whilst embodiments of the invention have been described with
reference to coatings applied to ampoules, the invention in certain
embodiments relates more generally to containers for containing
liquids, made of plastics material and comprising a coating of
metal or a metal compound. These containers can be made of polymer
comprising polyethylene or polypropylene and further can have a
maximum filled volume of up to 100 ml, preferably up to 50 ml, more
preferably up to 20 ml. The containers are useful for liquids
containing volatile substances which would otherwise permeate
plastics containers to an unacceptable degree.
[0041] Also provided by the present invention are a method of
reducing moisture egress from a container made of plastics
material, comprising applying to an outer surface of the container
a coating comprising a metal or a metal compound, and a method of
sealing a container made of plastics material, comprising applying
to an outer surface of the container a coating comprising a metal
or a metal compound. In these methods, the coating and its
application are as described with respect to the above embodiments
of the invention.
[0042] A further specific method of the invention is for sealing an
ampoule, wherein the ampoule comprises from 0.5 ml to 10 ml of an
inhalation pharmaceutical or an injectable pharmaceutical (e.g.
water or saline for injection) in a pharmaceutically acceptable
carrier, comprising applying to the ampoule a coating of a metal or
a metal compound over at least 70% of the outer surface of the
ampoule.
[0043] The coating of the invention has an additional or
alternative property, naming that a label can be applied onto the
coating. Hence, a further method of the invention is a method of
applying a label to an ampoule, comprising applying a coating of a
metal or a metal compound to the ampoule and applying the label to
the coating.
[0044] The label can be attached to the coated ampoule using
adhesive. The label can also be sprayed or printed onto the coated
ampoule.
[0045] The inventions in its varying embodiments has a number of
advantages, some or several or all of which may be seen in any
given embodiment. The ampoules are sealed by the invention;
reducing the loss e.g. of moisture and reducing contamination from
the outside. Because of the shape of the ampoules, the process
effectively seals each ampoule individually although ampoules may
still be made in strips of say 5, 10, 30 etc. This is an
improvement upon packaging a strip of ampoules in a pouch, as now
when an ampoule is removed from the strip the remaining ampoules
remain substantially sealed--contrast this with when a pouch
containing many ampoules is opened and all become exposed to the
environment.
[0046] Post application of the coating, it is relatively easy to
apply labels to the ampoules or print with conventional inks,
without the constraints upon choice of ink or presence of solvent
that applied previously.
[0047] Ampoules coated according to the invention with a metallic
coating have, in addition, a striking appearance. The coating has
been found to be continuous, non-flaky and resistant to abrasion
such as rubbing.
[0048] In relation to aspects of the invention in which other
plastic containers are coated, the method applies generally to
packaging used where the contents would be damaged by loss of or
contamination by gases and other volatiles, for example, vitamins,
flavours, perfumes etc. The invention provides packaging which is
of plastics material, e.g. LDP, and cheaper than glass,
trilaminates, ceramics etc.
[0049] The invention is now illustrated in the following examples,
with reference to the accompanying drawings, in which:--
[0050] FIG. 1 shows a view from the front of a strip of ten
ampoules coated with aluminium according to the invention;
[0051] FIGS. 2 and 3 shows the strip of FIG. 1 with one ampoule
being detached; and
[0052] FIG. 4 shows a view from the front of a strip of ten
ampoules coated with titanium according to the invention.
EXAMPLES
Example 1
[0053] A strip of 10 ampoules made from low density polyethylene
was prepared using a standard blow-fill-seal apparatus, each
ampoule containing 3 ml of salbutamol solution. The ampoules were
inspected visually to confirm correct filling of contents and
manually to confirm they were all intact. The strip of ampoules was
introduced into a filtered cathode arc coating machine fitted with
an aluminium target. The machine was closed and pumped down to
operating vacuum. The coating operation was begun and continued
until the coating thickness monitor indicated a thickness of 300
nm. The coating was stopped, the vacuum released and the chamber
opened.
[0054] The coated ampoules (1) are shown in FIGS. 1-3. The ten
ampoules exited the coating chamber intact--FIG. 1 and have a head
(3) which in use is twisted to break the neck (2) to release the
contents.
[0055] The resultant coated ampoules had a shiny, metallic
appearance, being completely coated with a thin layer of
aluminum.
[0056] The aluminum coating was continuous over the whole surface
of the ampoules, was smooth and without noticeable defects. The
coating was firmly adhered to the ampoules and did not detach and
resisted rubbing.
[0057] A single ampoule (4) was detached from the strip of 10--See
FIG. 2--without tearing of the coating at the junction (5) between
the detached ampoule and the remaining strip of nine ampoules.
[0058] The integrity of the ampoules was tested and it was
confirmed they remained intact and contained the same volume of
solution as prior to being coated. The contents of four ampoules
were tested independently using an atomic absorption based method
to determine whether there had been contamination by aluminium. In
each separate test, an aluminium content of less than 1 ppm was
recorded, beyond the lower limit of the detection method,
confirming that the aluminium content of the solution inside the
ampoule after coating was nil in each case. These results confirmed
that the ampoule wall had not been breached during the coating
process.
Example 2
[0059] A strip of 5 ampoules was made from low density polyethylene
using a standard blow-fill-seal apparatus, each ampoule containing
3 ml of saline solution. The ampoules were inspected visually to
confirm correct filling of contents and manually to confirm they
were all intact.
[0060] The strip of ampoules was introduced into a filtered cathode
vacuum arc apparatus fitted with a titanium target. The machine was
closed and pumped down to operating vacuum. The coating operation
was begun and continued until the coating thickness monitor
indicates a thickness of 300 nm. The coating was stopped, the
vacuum released and the chamber opened.
[0061] The resultant coated ampoules (6) are shown in FIG. 4 and
were found to have a shiny appearance, being substantially
completely coated with a thin layer of titanium, the coating being
slightly duller than the aluminum coating of Example 1.
[0062] The invention hence provides coated plastic containers and
methods of obtaining the same.
* * * * *