U.S. patent application number 10/739664 was filed with the patent office on 2004-07-08 for valves for use in containers having valve stems slidably movable within round-edged sealing rings.
Invention is credited to Anderson, Gregor John, McLennan, Godfrey, James William, Hailey, Mark Andrew, Russell, David Joseph.
Application Number | 20040129737 10/739664 |
Document ID | / |
Family ID | 32684031 |
Filed Date | 2004-07-08 |
United States Patent
Application |
20040129737 |
Kind Code |
A1 |
Anderson, Gregor John, McLennan ;
et al. |
July 8, 2004 |
Valves for use in containers having valve stems slidably movable
within round-edged sealing rings
Abstract
There is provided a valve for an aerosol container. The valve
comprises a valve body; within the valve body, a sealing ring and
receivable by the sealing ring, a valve stem having a dispensing
passage. The valve stem is slidably movable within the sealing ring
from a valve-closed position to a valve-open position in which the
interior of the valve body is in communication with the dispensing
passage. The sealing ring is shaped such as to reduce the contact
area between the sealing ring and the valve stem. Preferably, the
valve is a metering valve.
Inventors: |
Anderson, Gregor John,
McLennan; (Ware, GB) ; Hailey, Mark Andrew;
(Ware, GB) ; Russell, David Joseph; (Ware, GB)
; Godfrey, James William; (Ware, GB) |
Correspondence
Address: |
DAVID J LEVY, CORPORATE INTELLECTUAL PROPERTY
GLAXOSMITHKLINE
FIVE MOORE DR., PO BOX 13398
RESEARCH TRIANGLE PARK
NC
27709-3398
US
|
Family ID: |
32684031 |
Appl. No.: |
10/739664 |
Filed: |
December 18, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10739664 |
Dec 18, 2003 |
|
|
|
09937232 |
Sep 24, 2001 |
|
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|
Current U.S.
Class: |
222/402.24 |
Current CPC
Class: |
B65D 83/54 20130101;
B65D 83/48 20130101 |
Class at
Publication: |
222/402.24 |
International
Class: |
B65D 083/14 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 1999 |
GB |
9906640.9 |
Claims
1. Valve for an aerosol container, the valve comprising a valve
body; within said valve body, a sealing ring; and receivable by
said sealing ring, a valve stem having a dispensing passage, the
valve stem being slidably movable within the sealing ring from a
valve-closed position to a valve-open position in which the
interior of the valve body is in communication with the dispensing
passage, wherein the sealing ring is shaped such as to reduce the
contact area between the sealing ring and the valve stem.
2. Valve according to claim 1, wherein the area of contact between
the sealing ring and the valve stem is less than 90% of what the
area of contact would be if the sealing ring had square-cut
edges.
3. Valve according to either of claims 1 or 2, wherein the sealing
ring is formable by a moulding process.
4. Valve according to claim 3 wherein the moulding process is
injection moulding.
5. Valve according to claim 3 wherein the moulding process is
compression moulding.
6. Valve according to claim 3 wherein the moulding process is
transfer moulding.
7. Valve according to any of claims 1 to 6, wherein the sealing
ring is not movable relative to the valve body.
8. Valve according to claim 7, wherein the sealing ring is held
within a cavity in the valve body.
9. Valve according to any of claims 1 to 8, wherein the
stem-receiving part of the sealing ring has at least one rounded
edge.
10. Valve according to any of claims 1 to 9, wherein the
stem-receiving part of the sealing ring presents a lobed surface to
the stem.
11. Valve according to claim 10, wherein the lobed surface and the
system-receiving part of the stem define one or more wells.
12. Valve according to claim 11, wherein said one or more wells
contain lubricant material therein.
13. Valve according to any of claims 1 to 12, wherein the valve
body has a metering chamber, a sampling chamber and therebetween is
provided a second sealing ring within which the stem is slidably
movable, the valve stem having a transfer passage such that in the
valve-closed position the dispensing passage is isolated from the
metering chamber and the metering chamber is in communication with
the sampling chamber via said transfer passage, and in the
valve-open position the dispensing passage is in communication with
the metering chamber and the transfer passage is isolated from the
metering chamber, wherein the second sealing ring is shaped such as
to reduce the contact area between the second sealing ring and the
valve stem.
14. Valve according to claim 13, wherein the area of contact
between the second sealing ring and the valve stem is less than 90%
of what the area of contact would be if the second sealing ring had
square-cut edges.
15. Valve according to either of claims 13 or 14, wherein the
second sealing ring is formable by a moulding process.
16. Valve according to claim 15 wherein the moulding process is
injection moulding.
17. Valve according to claim 15 wherein the moulding process is
compression moulding.
18. Valve according to claim 15 wherein the moulding process is
transfer moulding.
19. Valve according to any of claims 13 to 18, wherein the second
sealing ring is not movable relative to the valve body.
20. Valve according to claim 19, wherein the second sealing ring is
held within a cavity in the valve body.
21. Valve according to any of claims 13 to 20, wherein the
stem-receiving part of the second sealing ring has at least one
rounded edge.
22. Valve according to any of claims 13 to 21, wherein the
stem-receiving part of the second sealing ring presents a lobed
surface to the stem.
23. Valve according to claim 22, wherein the lobed surface and the
stem-receiving part of the stem define one or more wells.
24. Valve according to claim 23, wherein said one or more wells
contain lubricant material therein.
25. Valve according to any of claims 1 to 24 wherein the sealing
ring comprises an elastomeric material.
26. Valve according to any of claims 13 to 25 wherein the second
sealing ring comprises an elastomeric material.
27. Valve according to claims 25 and 26 wherein the elastomeric
material is selected from the group consisting of (a) a
thermoplastic elastomer comprising a copolymer of about 80 to about
95 mole percent ethylene and a total of about 5 to about 20 percent
mole percent of one or more of 1-butene, 1-hexene and 1-octene; (b)
a styrene-ethylene/butylene-styrene block copolymer; (c) an
ethylene propylene diene rubber (EPDM) (d) a thermoplastic
elastomer blend of EPDM dispersed in a polypropylene or
polyethylene matrix; (e) a butyl polyethylene; (f) a
butyl-polypropylene; and any mixtures thereof.
28. Valve according to any of claims 1 to 27, wherein the sealing
ring additionally comprises lubricant material.
29. Valve according to any of claims 13 to 28, wherein the second
sealing ring additionally comprises lubricant material.
30. Valve according to any of claims 1 to 29, wherein the stem
comprises lubricant material.
31. Aerosol container comprising a valve according to any of claims
1 to 30.
32. Aerosol container according to claim 31 comprising a suspension
of a medicament in a propellant.
33. Aerosol container according to claim 32, wherein, the
propellant is liquefied HFA134a or HFA-227 or mixtures thereof.
34. Aerosol container according to either of claims 32 or 33,
wherein the medicament is selected from the group consisting of
albuterol, salmeterol, fluticasone propionate, beclomethasone
dipropionate, ipratropium bromide and salts or solvates thereof and
any combination thereof.
Description
[0001] This invention relates to a valve for an aerosol container
with the aid of which a quantity of the contents thereof can be
dispensed. The invention has particular application to the
dispensing of metered doses of medicaments, though it is applicable
to the dispensing of aerosols generally.
[0002] Containers for aerosol formulations commonly comprise a vial
body coupled to a valve. The valve comprises a valve stem through
which the formulation is dispensed. Generally the valve includes a
rubber valve seal intended to allow reciprocal movement of the
valve stem while preventing leakage of propellant from the
container.
[0003] It has been found that in some conventional devices the
valve stem tends to stick, pause, or drag during the actuation
cycle with the result that the valve stem may not move smoothly,
particularly when released. This may be partly caused by the drug
sedimenting or precipitating out of the drug-propellant suspension
or solution formulation and depositing on the internal valve
components, the presence of drug on the sliding interface creating
increased friction during operation.
[0004] Prior art seals generally comprise a rubber ring formed by
stamping out a ring shape from a sheet of rubber material. The ring
aperture, thus, inevitably has square-cut edges which present a
relatively high area of contact between the seal and the stem.
Furthermore, when the valve stem is moved in such square-cut seals
the seal deforms in such a way that the surface area, and hence the
frictional contact area, between the seal and stem increases.
[0005] The Applicants have now found that the above described
problem may be ameliorated without compromising sealing performance
if the valve seal is shaped such as to reduce the area of contact
between the seal and the stem. If a manufacturing process based
upon moulding is employed a ring may be formed having a ring
aperture with rounded or otherwise shaped edges. When such a
rounded or shaped-edge ring is used as a valve seal the area of
contact between the seal and the stem is less than that for a ring
of equivalent thickness having square-cut edges. On movement of the
stem within the seal there is also less tendency for the seal to
deform such as to increase the contact area between the seal and
the stem.
[0006] According to the present invention there is provided a valve
for an aerosol container, the valve comprising a valve body; within
said valve body, a sealing ring; and receivable by said sealing
ring, a valve stem having a dispensing passage, the valve stem
being slidably movable within the sealing ring from a valve-closed
position to a valve-open position in which the interior of the
valve body is in communication with the dispensing passage, wherein
the sealing ring is shaped such as to reduce the contact area
between the sealing ring and the valve stem.
[0007] Preferably, the area of contact between the sealing ring and
the valve stem is less than 90%, more preferably less than 70%,
most preferably less than 50% of what the area of contact would be
if the stem-receiving aperture of the sealing ring had square-cut
edges.
[0008] Preferably, the sealing ring is formable by a moulding
process.
[0009] Preferably, the moulding process is injection moulding.
[0010] Alternatively, the moulding process is compression
moulding.
[0011] Alternatively, the moulding process is transfer
moulding.
[0012] Preferably, the sealing ring is not movable relative to the
valve body, that is to say it is somehow fixed thereto. More
preferably, the sealing ring is held within a cavity in the valve
body.
[0013] In one aspect, the stem-receiving part of the sealing ring
has at least one rounded edge, preferably all stem-receiving edges
are rounded.
[0014] In another aspect, the stem-receiving part of the sealing
ring presents a lobed surface to the stern. That is to say the
surface comprises one or more lobe features. Preferably, the lobed
surface and the stem-receiving part of the stem define one or more
wells. More preferably, the one or more wells contain lubricant
material therein.
[0015] Preferably, the valve is a metering valve in which the valve
body has a metering chamber, a sampling chamber and therebetween is
provided a second sealing ring within which the stem is slidably
movable, the valve stem having a transfer passage such that in the
valve-closed position the dispensing passage is isolated from the
metering chamber and the metering chamber is in communication with
the sampling chamber via said transfer passage, and in the
valve-open position the dispensing passage is in communication with
the metering chamber and the transfer passage is isolated from the
metering chamber, wherein the second sealing ring is shaped such as
to reduce the contact area between the second sealing ring and the
valve stem.
[0016] Preferably, the area of contact between the second sealing
ring and the valve stem is less than 90%, more preferably less than
70%, most preferably less than 50% of what the area of contact
would be if the stem-receiving aperture of the second sealing ring
had square-cut edges.
[0017] Preferably, the sealing ring and any second sealing ring is
formable by a moulding process.
[0018] Preferably, the moulding process is injection moulding.
[0019] Alternatively, the moulding process is compression
moulding.
[0020] Alternatively, the moulding process is transfer
moulding.
[0021] Preferably, the second sealing ring is not movable relative
to the valve body.
[0022] More preferably, the second sealing ring is held within a
cavity in the valve body.
[0023] In one aspect, the stem-receiving part of the second sealing
ring has at least one rounded edge, preferably all stem-receiving
edges are rounded.
[0024] In another aspect, the stem-receiving part of the second
sealing ring presents a lobed surface to the stem. Preferably, the
lobed surface and the stem-receiving part of the stem define one or
more wells. More preferably, the one or more wells contain
lubricant material therein.
[0025] Preferably the sealing ring and/or second sealing ring
comprises an elastomeric material. The ring is typically
resiliently deformable.
[0026] The elastomeric material may either comprise a thermoplastic
elastomer (TPE) or a thermoset elastomer which may optionally be
cross-linked. The sealing ring may also comprise a thermoplastic
elastomer blend or alloy in which an elastomeric material is
dispersed in a thermoplastic matrix. The elastomers may optionally
additionally contain conventional polymer additives such as
processing aids, colorants, tackifiers, lubricants, silica, talc,
or processing oils such as mineral oil in suitable amounts.
[0027] Suitable thermoset rubbers include butyl rubbers,
chloro-butyl rubbers, bromo-butyl rubbers, nitrile rubbers,
silicone rubbers, flurosilicone rubbers, fluorocarbon rubbers,
polysulphide rubbers, polypropylene oxide rubbers, isoprene
rubbers, isoprene-isobutene rubbers, isobutylene rubbers or
neoprene (polychloroprene) rubbers.
[0028] Suitable thermoplastic elastomers comprise a copolymer of
about 80 to about 95 mole percent ethylene and a total of about 5
to about 20 mole percent of one or more comonomers selected from
the group consisting of 1-butene, 1-hexene, and 1-octene as known
in the art. Two or more such copolymers may be blended together to
form a thermoplastic polymer blend.
[0029] Another suitable class of thermoplastic elastomers are the
styrene-ethylene/butylene-styrene block copolymers. These
copolymers may additionally comprise a polyolefin (e.g.
polypropylene) and a siloxane.
[0030] Thermoplastic elastomeric material may also be selected from
one or more of the following: polyester rubbers, polyurethane
rubbers, ethylene vinyl acetate rubber, styrene butadiene rubber,
copolyether ester TPE, olefinic TPE, polyester amide TPE and
polyether amide TPE.
[0031] Other suitable elastomers include ethylene propylene diene
rubber (EPDM).
[0032] The EPDM may be present on its own or present as part of a
thermoplastic elastomer blend or alloy, e.g. in the form of
particles substantially uniformly dispersed in a continuous
thermoplastic matrix (e.g. polypropylene or polyethylene).
Commercially available thermoplastic elastomer blend and alloys
include the SANTOPRENE.TM. elastomers. Other suitable thermoplastic
elastomer blends include butyl-polyethylene (e.g. in a ratio
ranging between about 2:3 and about 3:2) and
butyl-polypropylene.
[0033] The above-mentioned elastomeric materials can be prepared
using methods known to those skilled in the art.
[0034] Preferably, the sealing ring and/or the second sealing ring
additionally comprises lubricant material. Suitably, the sealing
ring and/or the second sealing ring comprises up to 30%, preferably
from 5 to 20% lubricant material.
[0035] Preferably, the stem comprises lubricant material. Suitably,
the valve stem comprises up to 30%, preferably from 5 to 20%
lubricant material.
[0036] The term `lubricant` herein means any material which reduces
friction between the valve stem and seal. Suitable lubricants
include silicone oil or a fluorocarbon polymer such as
polytetrafluoroethane (PTFE) or fluoroethylene propylene (FEP).
[0037] Lubricant can be applied to the stem, sealing ring or second
sealing ring by any suitable process including coating and
impregnation, such as by injection or a tamponage process.
[0038] According to another aspect of the present invention, there
is provided an aerosol container comprising a valve as described
hereinabove.
[0039] Preferably, the aerosol container comprises a suspension of
a medicament in a propellant.
[0040] Preferably, the propellant is liquefied HFA134a or HFA-227
or mixtures thereof.
[0041] Preferably, the medicament is selected from albuterol,
salmeterol, fluticasone propionate, beclomethasone dipropionate and
ipratropium bromide and salts or solvates thereof and any
combination thereof.
[0042] The invention will now be described further with reference
to the accompanying drawing in which:
[0043] FIG. 1 is a section through a metering valve according to
the invention;
[0044] FIG. 2 is a close-up sectional view of a seal-stem contact
point in a valve according to the invention;
[0045] FIG. 3 is a close-up sectional view of a seal-stem contact
point in a valve according to the invention;
[0046] FIG. 4a is a close-up sectional view of a seal-stem contact
point in a prior art valve in a rest position; and
[0047] FIG. 4b is a close-up sectional view of a seal-stem contact
point in the valve of FIG. 4a in an active position.
[0048] A valve according to the invention is shown in FIG. 1 and
comprises a valve body 1 sealed in a ferrule 2 by means of
crimping, the ferrule itself being set on the neck of a container
(not shown) with interposition of a gasket 3 in a well-known
manner. The container is loadable with a suspension of medicament,
such as salmeterol xinafoate in liquid propellant HFA134a.
[0049] The valve body 1 is formed at its lower part with a metering
chamber 4, and its upper part with a sampling chamber 5 which also
acts as a housing for a return spring 6. The words "upper" and
"lower" are used for the container when it is in a use orientation
with the neck of the container and valve at the lower end of the
container which corresponds to the orientation of the valve as
shown in FIG. 1. Inside the valve body 1 is disposed a valve stem
7, a part 8 of which extends outside the valve through lower stem
seal 9 and ferrule 2. The stem part 8 is formed with an inner axial
or longitudinal canal 10 opening at the outer end of the stem and
in communication with a radial passage 11.
[0050] The upper portion of stem 7 has a diameter such that it can
pass slidably through an opening in an upper stem seal 12 and will
engage the periphery of that opening sufficiently to provide a
seal. The stem seals 9 and 12 are made by a moulding process and
have rounded points of contact with the valve stem 7. Upper stem
seal 12 is held in position against a step 13 formed in the valve
body 1 between the said lower and upper parts by a sleeve 14 which
defines the metering chamber 4 between lower stem seal 9 and upper
stem seal 12. The valve stem 7 has a passage 15 which, when the
stem is in the inoperative position shown, provides a communication
between the metering chamber 4 and sampling chamber 5, which itself
communicates with the interior of the container via orifice 16
formed in the side of the valve body 1.
[0051] Valve stem 7 is biased downwardly to the inoperative
position by return spring 6 and is provided with a shoulder 17
which abuts against lower stem seal 9. In the inoperative position
as shown in FIG. 1 shoulder 17 abuts against lower stem seal 9 and
radial passage 11 opens below lower stem seal 9 so that the
metering chamber 4 is isolated from canal 10 and suspension inside
cannot escape.
[0052] A ring 18 having a "U" shaped cross section extending in a
radial direction is disposed around the valve body below orifice 16
so as to form a trough 19 around the valve body. As seen in FIG. 1
the ring is formed as a separate component having an inner annular
contacting rim of a diameter suitable to provide a friction fit
over the upper part of valve body 1, the ring seating against step
13 below the orifice 16. However, the ring 18 may alternatively be
formed as an integrally moulded part of valve body 1.
[0053] To use the device the container is first shaken to
homogenise the suspension within the container. The user then
depresses the valve stem 7 against the force of the spring 6. When
the valve stem is depressed both ends of the passage 15 come to lie
on the side of upper stem seal 12 remote from the metering chamber
4. Thus a dose is metered within the metering chamber. Continued
depression of the valve stem will move the radial passage 11 into
the metering chamber 4 while the upper stem seal 12 seals against
the valve stem body. Thus, the metered dose can exit through the
radial passage 11 and the outlet canal 10.
[0054] Releasing the valve stem causes it to return to the
illustrated position under the force of the spring 6. The passage
15 then once again provides communication between the metering
chamber 4 and sampling chamber 5. Accordingly, at this stage liquid
passes under pressure from the container through orifice 16,
through the passage 15 and thence into the metering chamber 4 to
fill it.
[0055] FIG. 2 shows a cut-away detail of a seal-stem contact point
of a valve herein. The upright valve stem 108 which has a circular
cross-section is sealingly contacted by a sealing ring 112. The
ring aperture 130 of the sealing ring 112 has rounded edges. It may
be understood that the area of contact of the ring 112 with the
stem 108 is less than it would be if the ring 112 had square-cut
edges. When the stem 108 is moved upwards, the ring 112 will tend
to flex into free-space 140.
[0056] FIG. 3 shows a cut-away detail of a seal-stem contact point
of a second valve herein. The upright valve stem 208 which has a
circular cross-section is sealingly contacted by a sealing ring
212. The ring aperture of the sealing ring 212 is edged by two
rounded lobes 230, 232. The area of contact of the ring 212 with
the stem 208 is less than it would be if the ring 212 had
square-cut edges. When the stem 208 is moved within the ring 212,
the ring 212 will tend to flex into free-space 240 and well 242.
The well 242 may be wholly or partially filled with a lubricant
material.
[0057] FIGS. 4a and 4b show a cut-away detail of a seal-stem
contact point of a prior art valve, wherein FIG. 4a shows a rest
configuration and FIG. 4b shows the configuration when the valve is
in an active position. The upright valve stem 308 which has a
circular cross-section is sealingly contacted by a sealing ring
312. The ring aperture 330 of the sealing ring 312 has square-cut
edges 330. When the stem is moved upwards as shown in FIG. 4b, the
ring 312 is deformed and spreads out such that the area of contact
between the ring 312 and the stem 308 is increased. The frictional
contact between the ring 312 and stem is thus, also increased.
[0058] It may be appreciated that a number of different
configurations of the sealing ring are possible, in addition to
those described in FIGS. 2 and 3, in which the contact area between
the sealing ring and the valve stem is reduced. One possible
configuration is similar to that shown in FIG. 3 but the ring
aperture is edged by more than 2 lobes. Another possible
configuration has a sealing ring aperture with straight tapered
edges leading to a point (such that its cross section is triangular
in shape) which has reduced contact with the valve stem compared to
straight cut edges. A lobed version of this sealing ring is also
possible wherein there are two or more lobes each tapered to a
point. A further configuration which reduces the contact area with
the valve stem has sections of the top and bottom sides of the ring
aperture cut away to leave a smaller projecting portion to form a
seal with the valve stem. The projecting portion may have straight
cut or shaped edges. Cutting one or more grooves or small channels
in the non stem-receiving surfaces of the sealing ring provides
space for the stem-receiving part of the sealing ring to move into
upon movement of the valve stem, resulting in reduced deformation
and friction at the contact surface with the valve stem.
[0059] It may be appreciated that any of the parts of the metering
valve which contact the medicament suspension may be coated with
materials such as fluoropolymer materials which reduce the tendency
of medicament to adhere thereto. Suitable fluoropolymers include
polytetrafluoroethylene (PTFE) and fluoroethylene propylene (FEP).
Any movable parts may also have coatings applied thereto which
enhance their desired movement characteristics. Frictional coatings
may therefore be applied to enhance frictional contact and
lubricants used to reduce frictional contact as necessary.
[0060] The aerosol container and valve of the invention is suitable
for dispensing medicament, particularly for the treatment of
respiratory disorders such as asthma and chronic obstructive
pulmonary disease (COPD).
[0061] Appropriate medicaments may thus be selected from, for
example, analgesics, e.g., codeine, dihydromorphine, ergotamine,
fentanyl or morphine; anginal preparations, e.g., diltiazem;
antiallergics, e.g., cromoglycate, ketotifen or nedocromil;
antiinfectives e.g., cephalosporins, penicillins, streptomycin,
sulphonamides, tetracyclines and pentamidine; antihistamines, e.g.,
methapyrilene; anti-inflammatories, e.g., beclomethasone
dipropionate, fluticasone propionate, flunisolide, budesonide,
rofleponide, mometasone furoate or triamcinolone acetonide;
antitussives, e.g., noscapine; bronchodilators, e.g., albuterol,
salmeterol, ephedrine, adrenaline, fenoterol, formoterol,
isoprenaline, metaproterenol, phenylephrine, phenylpropanolamine,
pirbuterol, reproterol, rimiterol, terbutaline, isoetharine,
tulobuterol, or (-)-4-amino-3,5-dichloro-.alpha.-[[[6-[2-(2--
pyridinyl)ethoxy]hexyl]methyl] benzenemethanol; diuretics, e.g.,
amiloride; anticholinergics, e.g., ipratropium, tiotropium,
atropine or oxitropium; hormones, e.g., cortisone, hydrocortisone
or prednisolone; xanthines, e.g., aminophylline, choline
theophyllinate, lysine theophyllinate or theophylline; therapeutic
proteins and peptides, e.g., insulin or glucagon. It will be clear
to a person skilled in the art that, where appropriate, the
medicaments may be used in the form of salts, (e.g., as alkali
metal or amine salts or as acid addition salts) or as esters (e.g.,
lower alkyl esters) or as solvates (e.g., hydrates) to optimise the
activity and/or stability of the medicament.
[0062] Preferred medicaments are selected from albuterol,
salmeterol, fluticasone propionate and beclomethasone dipropionate,
and ipratropium bromide and salts or solvates thereof, e.g., the
sulphate of albuterol and the xinafoate of salmeterol.
[0063] Medicaments can also be delivered in combinations. Preferred
formulations containing combinations of active ingredients contain
salbutamol (e.g., as the free base or the sulphate salt) or
salmeterol (e.g., as the xinafoate salt) in combination with an
anti-inflammatory steroid such as a beclomethasone ester (e.g., the
dipropionate) or a fluticasone ester (e.g., the propionate).
[0064] It will be understood that the present disclosure is for the
purpose of illustration only and the invention extends to
modifications, variations and improvements thereto.
[0065] The application of which this description and claims form
part may be used as a basis for priority in respect of any
subsequent application. The claims of such subsequent application
may be directed to any feature or combination of features described
therein. They may take the form of product, method or use claims
and may include, by way of example and without limitation, one or
more of the following claims:
* * * * *