U.S. patent application number 10/130889 was filed with the patent office on 2002-12-19 for medicament dispenser.
Invention is credited to Rand, Paul Kenneth.
Application Number | 20020189612 10/130889 |
Document ID | / |
Family ID | 27447801 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020189612 |
Kind Code |
A1 |
Rand, Paul Kenneth |
December 19, 2002 |
Medicament dispenser
Abstract
There is provided a medicament dispenser having a body, a
medicament container, dose-liberating means, an energy store for
actuating said dose-liberating means and trigger means for directly
or indirectly releasing the energy store, wherein the trigger means
comprises a trigger coupling. The coupling is reversibly deformable
in response to the application of non-mechanical energy thereto.
The non-mechanical energy may comprise heat energy, electrical
current energy, electrical field energy or magnetic field
energy.
Inventors: |
Rand, Paul Kenneth; (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: |
27447801 |
Appl. No.: |
10/130889 |
Filed: |
May 23, 2002 |
PCT Filed: |
December 8, 2000 |
PCT NO: |
PCT/EP00/12388 |
Current U.S.
Class: |
128/200.23 ;
604/58 |
Current CPC
Class: |
A61M 2202/064 20130101;
A61M 15/0065 20130101; A61M 15/0023 20140204; A61M 15/0091
20130101; A61M 2205/825 20130101; A61M 2205/8206 20130101; A61M
15/009 20130101; A61M 2205/8212 20130101; A61M 15/0028 20130101;
A61M 15/0051 20140204; A61M 2205/6054 20130101; A61M 15/008
20140204; A61M 15/0043 20140204; A61M 2016/0039 20130101; A61M
2205/332 20130101; A61M 2205/3584 20130101; A61M 15/0068 20140204;
A61M 2205/0266 20130101; A61M 2205/3306 20130101 |
Class at
Publication: |
128/200.23 ;
604/58 |
International
Class: |
A61M 013/00; A61M
011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 11, 1999 |
GB |
99292815 |
Feb 25, 2000 |
GB |
00043596 |
May 10, 2000 |
GB |
00111245 |
Oct 31, 2000 |
GB |
00266486 |
Claims
1. A medicament dispenser comprising a body, a medicament
container, dose-liberating means, an energy store for actuating
said dose-liberating means and trigger means for directly or
indirectly releasing the energy store, wherein said trigger means
comprises a trigger coupling which is reversibly deformable in
response to the application of non-mechanical energy thereto.
2. A medicament dispenser according to claim 1 wherein the
dose-liberating means takes the form of a valve and/or a
dose-metering means, and/or aerosolization means, and/or
container-opening means, and/or a pump (e.g. an aqueous pump),
and/or a plunger (e.g. as in an automated syringe).
3. A medicament dispenser according to claim 2 wherein the
dose-metering means comprises a weight and/or a volume and/or a
time and/or a surface-area regulated mechanism.
4. A medicament dispenser according to claim 2 or claim 3 wherein
dose-metering means comprises a valve (for example, a linear or
rotary valve) and/or a piston and/or a load cell and/or a
plunger.
5. A medicament dispenser according to any one of claims 2 to 4
wherein the dose-metering means comprises at least one metering
chamber.
6. A medicament dispenser according to claim 5 wherein on actuation
of the dose-metering means, the or each metering chamber moves into
fluid communication with the reservoir.
7. A medicament dispenser according to claim 5 or claim 6 wherein
the dose-metering means and the reservoir are relatively rotatable
with respect to each other about a common central axis.
8. A medicament dispenser according to claim 7 wherein the or each
metering chamber is adapted to be in fluid communication
selectively with the reservoir or with the patient.
9. A medicament dispenser according to any one of claims 5 to 8
wherein the or each metering chamber has a variable volume.
10. A medicament dispenser according to any one of claims 5 to 8
wherein the or each metering chamber has a fixed volume which
metering volume is variable by insertion of a plunger or
piston.
11. A medicament dispenser according to claim 9 wherein the or each
metering chamber is formed from expandable material.
12. A medicament dispenser according to claim 9 wherein the or each
metering chamber has a telescopic or concertina arrangement.
13. A medicament dispenser according to any one of claims 5 to 12
further comprising a gas permeable dry powder retaining means below
the or each metering chamber.
14. A medicament dispenser according to claim 13 wherein the
retaining means is made from a gas-permeable filter, a mesh screen,
a porous material or a perforated chamber element.
15. A medicament dispenser according to claim 2 wherein the
aerosolization means comprises a container of compressed gas (e.g.
an inert gas or air), or a liquefied propellant under pressure.
16. A medicament dispenser according to claim 15 wherein the
aerosolization means comprises means to propel pressurised gas
through a metered dose.
17. A medicament dispenser according to claim 16 wherein the
gas-propelling means provides at least one pulse of gas on
actuation.
18. A medicament dispenser according to claim 16 or 17 wherein the
gas-propelling means provides one pulse of gas for each dose
dispensed.
19. A medicament dispenser according to any one of claims 16 to 18
wherein the gas is air.
20. A medicament dispenser according to any one of claims 16 to 18
wherein the gas is an inert gas.
21. A medicament dispenser according to any one of the preceding
claims wherein the medicament is pre-metered prior to actuation of
the trigger means by a patient.
22. A medicament dispenser according to claim 21 wherein
container-opening means liberates the medicament from the
medicament container for receipt by a patient.
23. A medicament dispenser according to any one of claims 15 to 22
wherein the aerosolization means liberates a pre-metered dose of
medicament for receipt by a patient.
24. A medicament dispenser according to any one of the preceding
claims additionally comprising a reset mechanism for resetting the
trigger means and/or the dose-liberating means after actuation
thereof.
25. A medicament dispenser according to claim 24, wherein the reset
mechanism comprises a reset coupling which is reversibly deformable
in response to the application of non-mechanical energy
thereto.
26. A medicament dispenser according to any of claims 1 to 25,
wherein said non-mechanical energy comprises electric current flow
through the coupling.
27. A medicament dispenser according to any of claims 1 to 26,
wherein the coupling comprises a wire, strip, coil or tube.
28. A medicament dispenser according to claim 27, wherein the
coupling comprises multiple wires, strips, coils or tubes.
29. A medicament dispenser according to any of claims 1 to 28,
wherein the coupling comprises one or more wires which contract in
response to the application of non-mechanical energy thereto.
30. A medicament dispenser according to claim 29, wherein the
coupling exhibits a degree of contraction of from 2% to 8% on
application of non-mechanical energy thereto.
31. A medicament dispenser according to claim 30, wherein the
coupling comprises an alloy which undergoes a phase transition on
application of nonmechanical energy thereto.
32. A medicament dispenser according to claim 31, wherein said
alloy is a nickel-titanium alloy.
33. A medicament dispenser according to claim 32, wherein said
nickel-titanium alloy comprises from 5% to 95% nickel by weight and
from 95% to 5% titanium by weight, preferably from 20% to 80%
nickel by weight and from 80% to 20% titanium by weight.
34. A medicament dispenser according to either of claims 32 or 33,
wherein said nickel-titanium alloy additionally comprises copper,
niobium or any mixtures thereof.
35. A medicament dispenser according to claim 31, wherein the alloy
is a copper-zinc-aluminium alloy or a copper-aluminium-nickel
alloy.
36. A medicament dispenser according to claim 31, wherein the alloy
has the composition defined as Ni.sub.65-x-yMn.sub.20+xGa.sub.15+y,
where x is between 3 atomic % and 15 atomic % and y is between 3
atomic % and 12 atomic %.
37. A medicament dispenser according to claim 31, wherein the alloy
has the composition defined as
(Ni.sub.aFe.sub.bCo.sub.c).sub.65-x-y(Mn.sub.d-
Fe.sub.eCo.sub.f).sub.20+x(Ga.sub.gSi.sub.hAl.sub.i).sub.15+y,
where x is between 3 atomic % and 15 atomic % and y is between 3
atomic % and 12 atomic %, and where a+b+c=1, where d+e+f=1, and
g+h+i=1.
38. A medicament dispenser according to claim 31, wherein the alloy
comprises an ion-exchange polymer composite.
39. A medicament dispenser according to claim 31, wherein the alloy
comprises a contractile polymer.
40. A medicament dispenser according to any of claims 29 to 39,
wherein said one or more wires have a diameter from 30 to 400
micrometers, preferably from 50 to 150 micrometers.
41. A medicament dispenser according to any of claims 29 to 40,
wherein the coupling comprises from two to twenty, preferably six
to twelve wires which contract in response to heating or
application of a magnetic field thereto.
42. A medicament dispenser according to any of claims 1 to 41,
wherein said strip comprises multiple layers of different
metals.
43. A medicament dispenser according to claim 42, wherein the strip
comprises a bimetallic strip.
44. A medicament dispenser according to either of claims 42 or 43,
wherein the strip comprises at least one piezoelectric
material.
45. A medicament dispenser according to any of claims 1 to 44,
wherein the coupling is deformable in response to heating arising
from electrical current flow in the range from 0.01 A to 100 A,
preferably from 0.1 A to 5 A.
46. A medicament dispenser according to any of claims 1 to 44,
wherein the coupling is deformable in response to a magnetic field
of from 0.01 to 100 Tesla.
47. A medicament dispenser according to any of claims 1 to 46,
additionally comprising an electrical energy source.
48. A medicament dispenser according to claim 47, wherein said
electrical energy source comprises a voltaic cell or battery of
voltaic cells.
49. A medicament dispenser according to claim 48, wherein said
voltaic cell or battery of voltaic cells is rechargeable.
50. A medicament dispenser according to claim 47, wherein said
electrical energy source comprises a photovoltaic cell or battery
of photovoltaic cells.
51. A medicament dispenser according to claim 47, wherein said
electrical energy source comprises a converter for converting
mechanical energy into electrical energy.
52. A medicament dispenser according to any of claims 47 to 51,
additionally comprising a controller for controlling the amount of
electrical current flow through the coupling or to an electromagnet
to provide a magnetic field.
53. A medicament dispenser according to any of claims 47 to 52,
additionally comprising a timer for controlling the duration of
electrical current flow through the coupling or to an electromagnet
to provide a magnetic field.
54. A medicament dispenser according to any of claims 47 to 53
additionally comprising a local electrical energy store.
55. A medicament dispenser according to any one of claims 47 to 54
wherein the additional energy source is mechanically-generated.
56. A medicament dispenser according to claim 55 wherein the energy
source comprises a biasable resilient member.
57. A medicament dispenser according to claim 56 wherein the
biasable resilient member is a spring.
58. A medicament dispenser according to claim 55 wherein the energy
source comprises a source of compressed fluid, preferably
compressed gas.
59. A medicament dispenser according to claim 55 wherein the energy
source comprises a chemical energy store, preferably a chemical
propellant or ignition mixture.
60. A medicament dispenser according to claim 55 wherein the energy
source comprises a physically explosive energy source.
61. A medicament dispenser according to any of claims 1 to 60,
wherein flow of electrical current through the coupling and hence,
actuation of the trigger means is responsive to a patient-actuable
mechanism.
62. A medicament dispenser according to claim 61, wherein said
mechanism comprises a button, switch or lever arrangement.
63. A medicament dispenser according to any of claims 1 to 62, in
the form of an inhaler for the delivery of inhalable
medicament.
64. A medicament dispenser according to claim 63, wherein heating
arising from flow of electrical current through the coupling and
hence, actuation of the trigger means is responsive to a
patient-actuable mechanism comprising a sensor which senses the
breath of a patient.
65. A medicament dispenser according to claim 64, wherein said
sensor comprises a breath-movable element which is movable in
response to the breath of a patient.
66. A medicament dispenser according to claim 65, wherein said
breath-movable element is selected from the group consisting of a
vane, a sail, a piston, a diaphragm and an impeller.
67. A medicament dispenser according to claim 64, wherein said
sensor comprises a pressure sensor for sensing the pressure profile
associated with the breath of a patient.
68. A medicament dispenser according to claim 64, wherein said
sensor comprises an airflow sensor for sensing the airflow profile
associated with the breath of a patient.
69. A medicament dispenser according to claim 64, wherein said
sensor comprises a temperature sensor for sensing the temperature
profile associated with the breath of a patient.
70. A medicament dispenser according to claim 64, wherein said
sensor comprises a moisture sensor for sensing the moisture profile
associated with the breath of a patient.
71. A medicament dispenser according to claim 64, wherein said
sensor comprises a gas sensor for sensing the oxygen or carbon
dioxide profile associated with the breath of a patient.
72. A medicament dispenser according to any of claims 63 to 71,
wherein the coupling is exposable to the airflow arising from
inhalation or expiration of the patient to assist in the cooling of
the coupling post-actuation of the trigger means.
73. A medicament dispenser according to any of claims 1 to 72
comprising an actuation counter for counting the number of
actuations of the trigger means or a dose counter for counting the
number of doses delivered.
74. A medicament dispenser according to claim 73, wherein the
actuation counter is independent of the coupling.
75. A medicament dispenser according to any of claims 1 to 74
additionally comprising an electronic control system for
controlling the supply of nonmechanical energy to the coupling.
76. A medicament dispenser according to claim 75, wherein the
electronic control system is capable of providing pulses of
non-mechanical energy to the coupling.
77. A medicament dispenser according to either of claims 75 or 76,
wherein the electronic control system is capable of receiving
inputs from electronic sensors locatable on the dispenser.
78. A medicament dispenser according to claim 77, additionally
comprising an electronic sensor selected from the group consisting
of a breath sensor, a shake sensor, a temperature sensor, an
infrared sensor and a patient ID sensor.
79. A medicament dispenser according to any one of the preceding
claims additionally comprising climate control means.
80. A medicament dispenser according to claim 79 wherein the
climate control means is actuable by the coupling.
81. A medicament dispenser according to claim 79 or claim 80
wherein the climate control means comprises means to (i) reduce
moisture increase in the dispenser; and/or (ii) maintain ambient
temperature; and/or (iii) dry the dispenser prior to actuation
thereof.
82. A medicament dispenser according to any one of claims 79 to 81
wherein the climate control means comprises a desiccant.
83. A medicament dispenser according to any one of claims 79 to 82
wherein the climate control means comprises a heater.
84. A medicament dispenser according to any one of claims 79 to 83
wherein the climate control means comprises a temperature and/or a
moisture sensor.
85. A medicament dispenser according to any one of the preceding
claims wherein the medicament is selected from the group consisting
of albuterol, salmeterol, fluticasone propionate, beclomethasone
dipropionate, salts or solvates thereof and any mixtures
thereof.
86. A medicament dispenser according to any one of the preceding
claims wherein the medicament container comprises medicament in dry
powder form.
87. A medicament dispenser according to any one of the preceding
claims wherein the dry powder medicament includes a pharmaceutical
excipient in dry powder form.
88. A medicament dispenser according to any one of the preceding
claims wherein the density of the dry powder medicament particles
is reduced relative to standard dry powder medicament.
89. A medicament dispenser according to any one of the preceding
claims wherein the dry powder medicament particles are
aerodynamically shaped to improve medicament delivery to the
patient.
90. A medicament dispenser according to any one of claims 86 to 89
wherein the medicament container is a dry powder reservoir.
91. A medicament dispenser according to any one of claims 1 to 85
wherein the medicament container comprises medicament in solution
or suspension form.
92. A medicament dispenser according to claim 91, wherein said
medicament container comprises a suspension of a medicament in a
propellant.
93. A medicament dispenser according to claim 92, wherein, said
propellant comprises liquefied HFA134a, HFA-227, helium or carbon
dioxide.
94. A medicament dispenser according to claim 91, wherein said
medicament container comprises a solution of a medicament in a
solvent.
95. A medicament dispenser according to any one of the preceding
claims additionally comprising a safety mechanism to prevent
unintended multiple actuations of the trigger means.
96. A medicament dispenser according to claim wherein the safety
mechanism imposes a time delay between successive actuation of the
trigger means.
97. A medicament dispenser according to any of the preceding claims
comprising a manual override enabling manual actuation of the
trigger means.
98. A medicament dispenser according to claim 97 comprising a child
resistance feature to prevent undesirable actuation thereof by
children.
99. An actuator for use in a medicament dispenser according to any
one of the preceding claims.
100. An actuator for a medicament container comprising a housing,
dose-liberating means, within said housing, a container seat for
receipt of the medicament container; on the housing or connecting
therewith, trigger means to actuate the dose-liberating means,
wherein the trigger means comprises a trigger coupling which is
reversibly deformable in response to the application of
non-mechanical energy thereto.
101. An actuator according to claim 99 or claim 100, wherein said
non-mechanical energy comprises electric current flow through the
coupling.
102. An actuator according to any of claims 99 to 101, wherein the
coupling comprises one or more wires which contract in response to
the application of non-mechanical energy thereto.
103. An actuator according to any of claims 99 to 102, wherein said
coupling comprises an alloy which undergoes a phase transition on
the application of non-mechanical energy thereto.
104. An actuator according to claim 103, wherein said alloy is a
nickel-titanium alloy.
105. An actuator according to any of claims 99 to 104 additionally
comprising an electronic control system for controlling the supply
of non-mechanical energy to the coupling.
106. An actuator according to claim 105, wherein the electronic
control system is capable of providing pulses of non-mechanical
energy to the coupling.
107. An actuator according to either of claims 105 or 106, wherein
the electronic control system is capable of receiving inputs from
electronic sensors locatable on the dispenser.
108. An actuator according to claim 107, additionally comprising an
electronic sensor selected from the group consisting of a breath
sensor, a shake sensor, a temperature sensor, an infrared sensor
and a patient ID sensor.
109. A medicament container for use in the dispenser according to
claims 1 to 98 and/or the actuator of claims 99 to 108.
110. Laboratory test apparatus for testing a medicament container
having trigger means comprising at least one actuator according to
any of claims 99 to 108 and a mounting for said at least one
actuator.
111. Kit of parts comprising a medicament dispenser according to
any of claims 1 to 98 in the form of a cartridge; and a housing
shaped for receipt of said cartridge.
Description
[0001] This invention relates to a medicament dispenser having
dose-liberating means and an energy store for actuating the
dose-liberating means. The dispenser is particularly suitable for
use as an inhalation device.
[0002] It is well known to treat patients with medicaments
contained in an aerosol, for example, in the treatment of
respiratory disorders. It is also known to use for such treatment,
medicaments which are contained in an aerosol and are administered
to a patient by means of an inhalation device comprising a tubular
housing or sleeve in which the aerosol container is located and an
outlet tube leading out of the tubular housing. Such inhalation
devices are generally referred to as metered dose inhalers (MDIs).
The aerosol containers used in such inhalation devices are designed
to deliver a predetermined dose of medicament upon each actuation
by means of an outlet valve member at one end which can be opened
either by depressing the valve member while the container is held
stationary or by depressing the container while the valve member is
held stationary. In the use of such devices, the aerosol container
is placed in the tubular housing with the outlet valve member of
the container communicating via a support with the outlet tube, for
example a nozzle or mouthpiece. When used for dispensing
medicaments, for example in bronchodilation therapy, the patient
then holds the housing in a more or less upright condition and the
mouthpiece or nozzle of the inhalation device is placed in the
mouth or nose of the patient. The aerosol container is pressed
towards the support to dispense a dose of medicament from the
container which is then inhaled by the patient.
[0003] It is also known to use dry powder inhalation devices for
the delivery of inhalable medicament. In one aspect, such
dispensers comprise pre-metered doses of powdered medicament, for
example in capsules or blisters. In another aspect, such dispensers
comprise a reservoir of powdered medicament from which doses are
metered prior to or concurrent with the delivery process. In either
case, the device may be designed for passive release of medicament,
where the medicament is simply made available at a delivery
position for aerosolisation in response to the inhalation of the
patient. Alternatively, an active release mechanism may be used
whereby a `puff` of compressed gas or air is provided to the
delivery position to assist in aerosolisation of the powder prior
to or concurrent with the inhalation of the patient. Such devices
are generally called active release dry powder inhalers (active
DPIs). The source of the compressed gas or air is generally an
aerosol container.
[0004] It is also well known to use syringes for the delivery of
injectable medicament to a patient. Traditional syringes rely on
puncturing of the patient's skin by a hollow needle through which
the injectable medicament (in solution or suspension form) is
delivered to the muscle or tissue of the patient. Recently
developed needleless systems for the delivery of injectables employ
high velocity injection of particle formulated drugs or vaccine
through the skin and into any physically accessible tissue. Other
needleless systems employ similar high velocity injection of drug
or vaccine coated on to a suitable carrier particle. Such
needleless systems may be configured to include a source of
compressed air or gas, which on release provides energy to propel
the medicament particles for injection into the skin.
[0005] It may be understood that effective delivery of medicament
to the patient using an inhalation device such as an MDI or active
DPI as described above is to an extent dependent on the patient's
ability to manually actuate the device (e.g. firing of the aerosol)
and to co-ordinate the actuation thereof with the taking of a
sufficiently strong inward breath. For some patients, particularly
young children, the elderly and the arthritic, manual actuation of
the device can present difficulties. Other patients find it
difficult to co-ordinate the taking of a reliable inward breath
with actuation of the device. Both of these sets of patients run
the risk that they do not receive the appropriate dose of
medicament.
[0006] It may also be understood that effective delivery of
medicament to the patient using a syringe or needleless injection
system as described above also requires care and dexterity.
[0007] The Applicants have now developed a medicament dispenser
which does not require manual actuation by the patient. In one
aspect, the dispenser comprises a medicament container,
dose-liberating means, an energy store for actuating the
dose-liberating means and trigger means for actuating the energy
store.
[0008] Actuation is responsive to the application of non-mechanical
energy to a coupling element of the trigger means. The
non-mechanical energy can be in the form of heat provided by
electrical current flow through the coupling element, which in turn
can be provided in response to the sensing of the breath of a
patient. Alternatively, the non-mechanical energy can be in the
form of a magnetic field provided by a suitable magnetic field
source such as a permanent magnet or an electromagnet.
[0009] U.S. Pat. No. 5,061,914 describes a shape memory alloy
micro-actuator. The actuator comprises a nickel-titanium alloy
material which undergoes a temperature induced phase transition
when heated. The phase transition results in contraction of the
actuator. The actuator can be mechanically coupled to a
micro-mechanical element for motion thereof.
[0010] U.S. Pat. No. 5,958,154 describes alloy materials which
undergo a phase transition in response to the application of a
magnetic field.
[0011] Accordingly, in one aspect the invention provides a
medicament dispenser comprising a body, a medicament container,
dose-liberating means, an energy store for actuating said
dose-liberating means and trigger means for directly or indirectly
releasing the energy store, wherein said trigger means comprises a
trigger coupling which is reversibly deformable in response to the
application of non-mechanical energy thereto.
[0012] As used herein, the term dose-liberating means refers to any
means associated with the dispenser for making a dose of medicament
available to a patient, for example, a dose-metering valve in an
aerosol container of medicament, means to aerosolize a dose of dry
powder medicament, means to uncover or open a sealed capsule of
pre-metered dry powder medicament, or means to pump a dose of
medicament for receipt by a patient. Thus, the dose-liberating
means may take the form of a valve, and/or dose-metering means,
and/or aerosolization means, and/or container-opening means, and/or
a pump (e.g. an aqueous pump), and/or a plunger (e.g. as in an
automated syringe).
[0013] As used herein, the term energy store refers to any store or
source that can release part or all of its stored energy in order
to actuate the dose-liberating means, for example, a spring,
compressed fluid, or an electrical or electromagnetic store.
[0014] Suitably, the valve is a slide valve. Other valve systems
include, but are not limited to, poppet valve systems, wedge gate
valve systems, double-disc gate valve systems, globe and angle
valve systems, swing check valve systems, end cock valve systems,
and other like valve systems. The valve design is typically a
function of providing a predetermined dosage or amount of the
medicament contained within the container to a user.
[0015] Where the medicament container is a pressurized aerosol
container, the valve typically comprises a valve body having an
inlet port through which a medicament aerosol formulation may enter
said valve body, an outlet port through which the aerosol may exit
the valve body and an open/close mechanism by means of which flow
through said outlet port is controllable.
[0016] The valve may be a slide valve wherein the open/close
mechanism comprises a sealing ring and receivable by the sealing
ring a valve stem having a dispensing passage, the valve stem being
slidably movable within the ring from a valve-closed to a
valve-open position in which the interior of the valve body is in
communication with the exterior of the valve body via the
dispensing passage.
[0017] Typically, the valve is a metering valve. The metering
volumes are typically from 10 to 100 .mu.l, such as 25 .mu.l, 50
.mu.l or 63 .mu.l. Suitably, the valve body defines a metering
chamber for metering an amount of medicament formulation and an
open/close mechanism by means of which the flow through the inlet
port to the metering chamber is controllable. Preferably, the valve
body has a sampling chamber in communication with the metering
chamber via a second inlet port, said inlet port being controllable
by means of an open/close mechanism thereby regulating the flow of
medicament formulation into the metering chamber.
[0018] The valve may also comprise a `free flow aerosol valve`
having a chamber and a valve stem extending into the chamber and
movable relative to the chamber between dispensing and
non-dispensing positions. The valve stem has a configuration and
the chamber has an internal configuration such that a metered
volume is defined therebetween and such that during movement
between is non-dispensing and dispensing positions the valve stem
sequentially: (i) allows free flow of aerosol formulation into the
chamber, (ii) defines a closed metered volume for pressurized
aerosol formulation between the external surface of the valve stem
and internal surface of the chamber, and (iii) moves with the
closed metered volume within the chamber without decreasing the
volume of the closed metered volume until the metered volume
communicates with an outlet passage thereby allowing dispensing of
the metered volume of pressurized aerosol formulation. A valve of
this type is described in U.S. Pat. No. 5,772,085.
[0019] The valve may also have a structure and action similar to
those aerosol valves described in European Patent Application No.
EP-A-870,699 and PCT Patent Application No. W099/36334.
[0020] The dose-metering means may comprise a volume and/or a time
and/or a surface-area regulated mechanism.
[0021] In one embodiment the dose-metering means may comprise a
valve as described hereinabove (for example, a linear or rotary
valve) and/or a piston and/or a load cell and/or a plunger.
[0022] Preferably, the dose-metering means comprises at least one
metering chamber.
[0023] On actuation of the dose-metering means, the or each
metering chamber may move into fluid communication with the
reservoir.
[0024] Alternatively, or in addition, the dose-metering means and
the reservoir may be relatively rotatable with respect to each
other about a common central axis.
[0025] In one embodiment the or each metering chamber is adapted to
be in fluid communication selectively with the reservoir or with
the patient.
[0026] The or each metering chamber may have a variable volume.
[0027] The or each metering chamber may have a fixed volume which
metering volume is variable by insertion of a plunger or
piston.
[0028] The or each metering chamber may be formed from expandable
material.
[0029] The or each metering chamber may have a telescopic or
concertina arrangement.
[0030] In one embodiment, there may be a gas permeable dry powder
retaining means below the or each metering chamber. The retaining
means may be made from a gas-permeable filter, a mesh screen, a
porous material or a perforated chamber element.
[0031] The aerosolization means may comprise a container of
compressed gas (e.g. an inert gas or air), or a liquefied
propellant under pressure.
[0032] The aerosolization means may comprise means to propel
pressurised gas through a metered dose. The gas-propelling means
may provide at least one pulse of gas on actuation. The
gas-propelling means may provide one pulse of gas for each dose
dispensed. The gas may be air or an inert gas.
[0033] In one embodiment, the medicament dispenser is in the form
of an active dry powder inhaler in which a "puff" of compressed air
or gas (e.g. helium) is delivered from the aerosolisation means,
such as an aerosol container, to aerosolize a dose of released dry
powder medicament.
[0034] In another embodiment, the medicament dispenser is in the
form of a needleless injection system in which compressed air or
gas (e.g. helium) is delivered at high velocity from the aerosol
container to propel a dose of dry powder medicament for injection
into the skin.
[0035] Thus, suitably the aerosol container, which as used herein
refers to any suitable container for comprising liquefied gas under
pressure, comprises a compressed air or gas (e.g. helium).
[0036] In another aspect, the medicament container may be arranged
for rupture in response to firing of the aerosolisation means.
[0037] In one embodiment, the medicament is pre-metered prior to
actuation of the dispenser by the patient, for example, the
medicament is pre-metered in capsules, strip or tape form.
[0038] The container-opening means may liberate the medicament from
the medicament container for receipt by a patient.
[0039] The aerosolization means may liberate a pre-metered dose of
medicament for receipt by a patient.
[0040] The pump may comprise a pump mechanism such as might be
found in a dispenser for dispensing liquid or solution (e.g.
aqueous solution) form medicament. The pump may deliver the
medicament directly to the patient (e.g. as a nasal spray) or the
pump may deliver the medicament to an intermediate position at
which further energy is supplied thereto to further propel,
aerosolize or otherwise direct the medicament dose to the
patient.
[0041] The dose-liberating means may comprise multiple plungers and
multiple syringe chambers. The syringe contents may for example, be
liquid, solutions, suspensions, particulates or in freeze-dried
form. A retract or reset mechanism is typically provided for the
plunger.
[0042] Traditional syringes rely on puncturing of the patient's
skin by a hollow needle through which the injectable medicament (in
solution or suspension form) is delivered to the muscle or tissue
of the patient. Recently developed neeedleless systems for the
delivery of injectables employ high velocity injection of particle
formulated drugs or vaccine through the skin and into any
physically accessible tissue. Other needleless systems employ
similar high velocity injection of drug or vaccine coated onto a
suitable carrier.
[0043] A reset mechanism may be provided for resetting the trigger
means and/or the dose-liberating means after actuation thereof. The
reset mechanism may for example, comprise a spring, motor,
mechanical arrangement or a reset coupling which is reversibly
deformable in response to the application of non-mechanical energy
thereto.
[0044] The term `non-mechanical energy` herein is used to mean
essentially any energy type which is not mechanical energy. The
coupling and any reset coupling herein typically comprise a
material which deforms, or undergoes a phase transition in response
to the application of non-mechanical energy, thereby resulting in a
change in shape/dimension of the coupling which serves to actuate
the trigger means. In embodiments the energy may be in the form of
heat energy, electrical current energy, electrical field energy and
magnetic field energy.
[0045] Preferably, the non-mechanical energy comprises electric
current flow through the coupling or reset coupling.
[0046] Preferably, the coupling or reset coupling comprises a wire,
strip, coil or tube.
[0047] Arrangements comprising multiple strips, wires, coils, or
tubes are also envisaged. The multiple strips, wires, coils, or
tubes may be arranged in any suitable fashion including parallel or
series arrangements and bundle arrangements.
[0048] The coupling may be coated with any suitable coating, or
encased within any suitable encasing including a shrink-wrap
sheath.
[0049] In one particular aspect, the coupling or reset coupling
comprises one or more wires which contract in response to
application of non-mechanical energy thereto.
[0050] Preferably, the degree of contraction of the coupling is
from 2% to 8%.
[0051] In embodiments, the coupling comprises an alloy which
undergoes a phase transition on heating (shape memory alloys).
Certain shape memory alloys also undergo a change in shape on
re-cooling without externally applied energy. Such two way shape
memory alloys are also envisaged for use herein.
[0052] In one embodiment, the shape memory alloy is preferably a
nickel-titanium alloy such as a nickel-titanium alloy comprising
from 5% to 95%, preferably from 20% to 80%, nickel by weight and
from 95% to 5%, preferably from 80% to 20%, titanium by weight. By
nickel-titanium alloy it is meant an alloy comprised essentially of
nickel and titanium, although other elements such as Cu and Nb may
be present in small (e.g. trace) amounts.
[0053] In other embodiments, the shape memory alloy is preferably a
copper-aluminium-nickel alloy or a copper-zinc-aluminium alloy.
Trace amounts of other elements may also be present.
[0054] In further embodiments, the coupling comprises an alloy
which undergoes a phase transition on application of a magnetic
field thereto (magnetic shape memory alloys). These materials are
generally intermetallic, ferromagnetic alloys that exhibit twin
variants in the martensitic, or low-temperature, phase of the
material. Suitable magnetic shape memory alloys are for example,
described in U.S. Pat. No. 5,958,154.
[0055] In one embodiment, the magnetic shape memory alloy exhibits
an austenitic crystal structure above a characteristic phase
transformation temperature and also exhibits a martensitic twinned
crystal structure below the phase transformation temperature. The
alloy has a magnetocrystalline anisotropy energy that is sufficient
to enable motion of twin boundaries of the martensitic twinned
crystal structure in response to application of a magnetic field to
the martensitic twinned crystal structure.
[0056] Where a magnetic shape memory alloy is employed the
medicament dispenser preferably includes a magnetic field source
disposed with respect to the coupling in an orientation that
applies to the coupling a magnetic actuation field in a direction
that is substantially parallel with a selected twin boundary
direction of the martensitic twinned crystal structure of the
coupling material.
[0057] Alternatively, the medicament dispenser preferably includes
a magnetic bias field source disposed with respect to the coupling
in an orientation that applies a magnetic bias field to the
coupling, and a magnetic actuation field source disposed with
respect to the coupling in an orientation that applies a magnetic
actuation field to the coupling material in a direction that is
substantially perpendicular to the orientation of the applied
magnetic bias field.
[0058] A preferred magnetic shape memory alloy is the actuator
material comprising an alloy composition defined as
Ni.sub.65-x-yMn.sub.20+xGa.sub- .15+y, where x is between 3 atomic
% and 15 atomic % and y is between 3 atomic % and 12 atomic %.
Preferably, the actuator material comprises an alloy composition
defined as Ni.sub.65-x-yMn.sub.20+xGa.sub.15+y, where x is between
6 atomic % and 10 atomic % and y is between 5 atomic % and 9 atomic
%; or where x is between 12 atomic % and 15 atomic % and y is
between 3 atomic % and 6 atomic %; or where x is between 10 atomic
% and 14 atomic % and y is between 3 atomic % and 6 atomic %; or
where x is between 7 atomic % and 11 atomic % and y is between 3
atomic % and 7 atomic %. In a particularly preferred aspect, the
alloy is Ni.sub.50Mn.sub.25Ga.sub.25.
[0059] Another preferred magnetic shape memory alloy is the alloy
having the composition
(Ni.sub.aFe.sub.bCo.sub.c).sub.65-x-y(Mn.sub.dFe.sub.eCo.-
sub.f).sub.20+x(Ga.sub.gSi.sub.hAl.sub.i).sub.15+y, where x is
between 3 atomic % and 15 atomic % and y is between 3 atomic % and
12 atomic %, and where a+b+c=1, where d+e+f=1, and g+h+i=1.
[0060] In preferred aspects, b is between zero and 0.6, c is
between zero and 0.6, and e, f, h and i are each zero; or b and c
are each zero, e is between zero and 0.6, f is between zero and
0.6, and h and i are each zero; or b, c, e and f are each zero, h
is between zero and 0.5, and i is between zero and 0.5.
[0061] Other suitable shape memory alloys include those based on
ion-exchange polymer composites such as are described in `Ionic
Polymer-Metal Composites (IPMC) As Biomimetic Sensors, Actuators
& Artificial Muscles--A Review`, M. Shahinpoor, Y. Bar-Cohen,
J. O. Simpson and J. Smith as published at
http://www.unm.edu/.about.amri/paper.html.
[0062] Other potentially suitable shape memory alloys include those
based on contractile polymers such as are described in `Review of
Artificial Muscle based on Contractile Polymers`, Massachusetts
Institute of Technology Artificial Intelligence Laboratory Memo No.
1330, November 1991, David L. Brock.
[0063] Preferably, the one or more wires have a diameter from 30 to
400 micrometers, preferably from 50 to 150 micrometers.
[0064] Preferably, the coupling comprises from two to twenty,
preferably six to twelve wires which contract in response to the
application of non-mechanical energy thereto. The wires may be
arranged in any suitable fashion including parallel or series
arrangements and bundle arrangements.
[0065] In another aspect, the coupling comprises a strip which
comprises multiple layers of different metals. Suitable strips
typically comprise a plurality of layers of material, each material
having a different coefficient of thermal expansion.
[0066] Preferred examples of strips include those comprising
multiple layers of different metals (e.g. bimetallic strips) and
strips comprising at least one piezoelectric material. Suitable
piezoelectric materials include piezoelectric ceramics, such as
compounds of lead zirconate and lead titanate, and piezoelectric
crystals which are generally polycrystalline ferroelectric
materials with the perovskite structure. Such piezoelectric
materials generally deform in response to the application of an
electric field.
[0067] In one aspect, the coupling is deformable in response to
heating arising from electrical current flow in the range from 0.01
A to 100 A, preferably from 0.1 A to 5 A.
[0068] In another aspect, the coupling is deformable in response to
the application of an electrical field, particularly where the
coupling comprises a piezoelectric material.
[0069] In a further aspect, the coupling is deformable in response
to a magnetic field of from 0.01 to 100 Tesla. The magnetic field
may for example, be produced by a permanent magnet or by an
electromagnet.
[0070] Preferably, the medicament dispenser additionally comprises
an electrical energy source for providing electric current, or for
providing an electric field, or for powering an electromagnet to
provide a magnetic field. In one aspect, the electrical energy
source comprises a voltaic cell or battery of voltaic cells which
may be rechargeable. In another aspect, the electrical energy
source comprises a photovoltaic cell or battery of photovoltaic
cells. In a further aspect, the electrical energy source comprises
a converter for converting mechanical energy into electrical
energy. In a further aspect, the electrical energy source comprises
a capacitor for local storage of charge. Suitable capacitors
comprise those known as `super capacitors` with a high capacitance
to size ratio, such as those consisting of solid electrodes and
liquid electrolyte.
[0071] Any known systems for power management and conservation may
be employed with the electrical energy source to manage and/or
conserve the power output thereof.
[0072] Energy may be conserved by a variety of means to enable the
device to operate for longer on a given source of energy, such as a
battery. Energy conservation or saving methods have additional
advantages in terms of reducing the size requirements of the power
source (e.g. battery) and thus the weight and portability of the
inhalation device.
[0073] A variety of energy saving methods are available which
generally involve reducing power consumption. One such method is to
use a clock or timer circuit to switch the power on and off at
regular or predetermined intervals. In another method the system
can selectively switch on/off specific electronic devices, such as
visual display units or sensors, in order to power these devices
only when they are required to perform a particular sequence of
events. Thus different electronic devices may be switched on and
off at varying intervals and for varying periods under control of
the system. The power sequencing system may also respond to a
sensor, such as a motion or breath sensor, which is activated on
use of the device.
[0074] Low power or "micropower" components should be used within
the electronics where possible and if a high power device is
required for a particular function this should be put into a low
power standby mode or switched off when not required. Similar
considerations apply in the selection of transducers.
[0075] Operation at low voltage is desirable since power
dissipation generally increases with voltage.
[0076] For low power digital applications complementary metal oxide
semi-conductor (CMOS) devices are generally preferred and these may
be specially selected by screening for low quiescent currents.
Clock speeds of processors and other logic circuits should be
reduced to the minimum required for computational throughput as
power consumption increases with frequency. Supply voltages should
also be kept at minimal values consistent with reliable operation
because power dissipation in charging internal capacitance's during
switching is proportional to the square of the voltage. Where
possible, supply voltages should be approximately the same
throughout the circuit to prevent current flowing through input
protection circuits. Logic inputs should not be left floating and
circuits should be arranged so that power consumption is minimised
in the most usual logic output state. Slow logic transitions are
undesirable because they can result in relatively large class-A
currents flowing. Resistors may be incorporated in the power supply
to individual devices in order to minimise current in the event of
failure.
[0077] In some control applications, devices that switch between on
and off states are preferred to those that allow analog (e.g.
linear) control because less power is dissipated in low resistance
on states and low current off states. Where linear components are
used (e.g. certain types of voltage regulators) then types with low
quiescent currents should be selected. In some circuit
configurations it is preferable to use appropriate reactive
components (i.e. inductors and capacitors) to reduce power
dissipation in resistive components.
[0078] Any electrical circuit may incorporate voltage amplification
means for generating a higher voltage than that supplied by the
voltaic cell or battery of voltaic cells, for example a step-up or
inverting switching circuit or a dc-dc converter incorporating an
oscillator, transformer and rectifier.
[0079] The electrical circuit may incorporate one or more energy
storage components such as capacitors or inductors in order to
supply a high enough instantaneous current to raise the temperature
of the strips or wires at the required rate to the required
temperature.
[0080] The input to the electrical circuit may be connected to the
electrical energy source by means of a mechanical,
electromechanical or electronic switching component.
[0081] The output of the electrical circuit may be connected to the
strips or wires or to an electromagnet by means of a mechanical,
electro-mechanical or electronic switching component or by a
component allowing the output current to be controlled in a linear
or digital (e.g. pulse width modulated) manner.
[0082] Suitable control profiles (e.g. via pulse width modulation)
include those where the temperature of a shape memory alloy
coupling is initially raised to a holding temperature (H) which is
just below the transition temperature (T). Actuation of the
coupling is then achievable by heating the coupling to a
temperature (A) just above the transition temperature. This can be
achieved rapidly because the holding temperature (H) is close to
the transition temperature (T). When the source of heating is
switched off, deactuation also occurs rapidly because the cooling
from a temperature (A) only just above the transition temperature
(T) to the transition temperature involves only a small temperature
decrease.
[0083] The strip or wire components may be powered from the battery
using a switching component without additional power supply
circuitry.
[0084] Suitably, the medicament dispenser additionally comprises a
controller for controlling the amount of electrical current flow
through the coupling or to an electromagnet.
[0085] Suitably, the medicament dispenser additionally comprises a
timer for controlling the duration of electrical current flow
through the coupling or to an electromagnet.
[0086] Suitably, the medicament dispenser additionally comprises a
local electrical source such as a capacitor or inductor.
[0087] The additional energy source may be mechanically generated,
for example, the energy source may comprise a biasable resilient
member e.g. a spring. Alternatively, the energy source may comprise
a source of compressed fluid, preferably compressed gas. The energy
source may comprise a chemical energy source or a physically
explosive energy source.
[0088] Preferably, deformation of the coupling and hence, actuation
of the trigger means is responsive to a patient-actuable
mechanism.
[0089] In one aspect, said mechanism comprises a button, switch or
lever arrangement.
[0090] In another aspect, the medicament dispenser is in the form
of an inhaler for the delivery of inhalable medicament. Preferably,
deformation of the coupling and hence, actuation of the trigger
means is responsive to a patient-actuable mechanism comprising a
sensor which senses the breath of a patient. The deformation of the
coupling (e.g. by electrical current flow therethrough) may be
responsive to the detection of the inward breath of a patient.
Alternatively, deformation of the coupling (e.g. by electrical
current flow therethrough) may be responsive to a mechanism coupled
to any point in the breathing pattern of the patient, such as the
end of the outward breath.
[0091] In one aspect, the sensor comprises a breath-movable element
which is movable in response to the breath of a patient.
Preferably, the breath-movable element is selected from the group
consisting of a vane, a sail, a piston, a diaphragm and an
impeller.
[0092] Movement of the breath-movable element may be detectable by
any suitable technique for detecting movement. Suitable techniques
include optical detectors, magnetic detectors or detectors using
detection of capacitative effects.
[0093] Optical detectors may be used to detect movement of the
breath-movable element by providing the element with a patterned
outer surface, for example strips in a barcode type arrangement,
and locating the optical detector so that it points towards the
patterned surface. Movement of the breath-movable element alters
the amount of the light source which reflects back onto the optical
detector as the beam passes over the patterned surface. The strips
may be arranged so that the direction of movement of the element
can be detected.
[0094] Magnetic detectors may be used to detect the movement of
breath-movable element by the use of a magnetic switch device. A
reader is located on the dispenser and magnetic material embedded
within the breath-movable element (or vice-versa). Movement of the
breath-movable element results in a change of the magnetic field
experienced by the reader. Alternatively, a Hall effect device can
be used whereby a semiconductor measures the strength of the
magnetic field of the magnetic material on the breath-movable
element.
[0095] Detection of capacitative effects may be used to detect
movement of the breath-movable element by adding a conductive part
to the element and also to a second fixed part of the dispenser.
Movement of the breath-movable element results in a change in
capacitance which can be measured.
[0096] In another aspect, the sensor comprises a pressure sensor
for sensing the pressure profile associated with the breath of a
patient. A pressure transducer is an example of a suitable pressure
sensor.
[0097] In another aspect, the sensor comprises an airflow sensor
for sensing the airflow profile associated with the breath of a
patient.
[0098] In another aspect, the sensor comprises a temperature sensor
for sensing the temperature profile associated with the breath of a
patient.
[0099] In another aspect, the sensor comprises a moisture sensor
for sensing the moisture profile associated with the breath of a
patient.
[0100] In another aspect, the sensor comprises a gas sensor for
sensing the oxygen or carbon dioxide profile associated with the
breath of a patient. The chemical profile of the inhaled and
exhaled part of the breath cycle varies and this further may be
used as a measurement tool.
[0101] Suitably, the breath data includes breath cycle data,
FEV.sub.1 and/or peak flow data.
[0102] In one aspect, the coupling is exposable to the airflow
arising from the inhalation or expiration of the patient to assist
in the cooling of the coupling post-actuation of the trigger means.
Other active cooling mechanisms may be employed, such as fan
cooling.
[0103] Preferably the medicament dispenser comprises an actuation
or dose counter for counting the number of actuations of the
trigger means. The actuation or dose counter may be mechanical or
electronic. More preferably the actuation or dose counter is
independent of the coupling so that counting will occur even if the
trigger means is manually actuated.
[0104] Suitably, the medicament dispenser additionally comprises an
electronic data management system. The electronic data management
system has input/output capability and comprises a memory for
storage of data; a microprocessor for performing operations on said
data; and a transmitter for transmitting a signal relating to the
data or the outcome of an operation on the data.
[0105] Suitably, the electronic data management system comprises an
electronic control system for controlling the supply of energy to
the coupling. Thus, in aspects the control system may regulate flow
of electrical current to the coupling or to any heater or
electromagnet source associated therewith.
[0106] The control system may form part of a larger electronic data
management system capable of receiving inputs from other electronic
components. In particular, inputs may be received from any sensor
to enable actuation of the coupling in response to sensor,
particularly breath sensor input.
[0107] The control system may be arranged to accomplish any
suitable control of actuation of the coupling including varying the
amount of energy supplied thereto, the rate of energy supplied
thereto, pulsing patterns of energy supply to the coupling, and
more complex control patterns.
[0108] Suitably, the electronic data management system is arranged
to be responsive to or activated by the voice of a user. Thus, for
example the system may be switched on or off in response to a voice
command.
[0109] The electronic data management system may be integral with
the body. Alternatively, the electronic data management system
forms part of a base unit which is reversibly associable with the
body.
[0110] Suitably, the medicament dispenser additionally comprises a
data input system for user input of data to the electronic data
management system. Preferably, the data input system comprises a
man machine interface (MMI) preferably selected from a keypad,
voice or noise recognition interface, graphical user interface
(GUI) or biometrics interface.
[0111] Suitably, the system additionally comprises a visual display
unit for display of data from the electronic data management system
to the user. The display may for example, comprise a screen such as
an LED or LCD screen. More preferably the visual display unit is
associable with the housing. More basic display units are envisaged
also including those in which a light or pattern of lights is
employed to act as a signal to the patient.
[0112] The electronic data management system may further comprise a
voice synthesiser for verbal communication of data, instructions
and feedback to a user.
[0113] Suitably, the medicament dispenser additionally comprises a
datalink for linking to a local data store to enable communication
of data between the local data store and the electronic data
management system. The datastore may also comprise data management,
data analysis and data communication capability.
[0114] The datastore may itself form part of a portable device
(e.g. a handheld device) or it may be sized and shaped to be
accommodated within the patient's home. The datastore may also
comprise a physical storage area for storage of replacement
medicament containers. The datastore may further comprise a system
for refilling medicament from a reservoir of medicament product
stored therewithin. The datastore may further comprise an
electrical recharging system for recharging any electrical energy
store on the medicament dispenser, particularly a battery
recharging system.
[0115] The datalink may for example enable linking with a docking
station, a personal computer, a network computer system or a
set-top box by any suitable method including a hard-wired link, an
infra red link or any other suitable wireless communications
link.
[0116] Suitably, the medicament dispenser additionally comprises an
actuation detector for detecting actuation of the trigger means
wherein said actuation detector transmits actuation data to the
electronic data management system.
[0117] The medicament dispenser may additionally comprise a safety
mechanism to prevent unintended multiple actuations of the trigger
means. The patient is thereby protected from inadvertently
receiving multiple doses of medicament in a situation where they
take a number of short rapid breaths. More preferably, the safety
mechanism imposes a time delay between successive actuations of the
release means. The time delay is typically of the order of from
three to thirty seconds.
[0118] Suitably, the medicament dispenser additionally comprises a
release detector for detecting release of medicament from the
medicament container, wherein said release detector transmits
release data to the electronic data management system.
[0119] Suitably, the medicament dispenser additionally comprises a
shake detector for detecting shaking of the medicament container
(e.g. prior to actuation of the trigger means), wherein said shake
detector transmits shake data to the electronic data management
system.
[0120] Suitably, the electronic data management system includes a
predictive algorithm or look-up table for calculating the optimum
amount of medicament to dispense.
[0121] Suitably, the memory on the electronic data management
system includes a dose memory for storing dosage data and reference
is made to the dose memory in calculating the optimum amount of
medicament to dispense.
[0122] Suitably, the medicament dispenser additionally comprises a
selector for selecting the amount of medicament to dispense from
the dispenser. In one aspect, the selector is manually operable. In
another aspect, the selector is operable in response to a signal
from the transmitter on the electronic data management system.
[0123] Suitably, the medicament dispenser comprises in association
with a body or housing thereof, a first transceiver for
transmitting and receiving data and in association with the
medicament container, a second transceiver for transmitting and
receiving data, wherein data is transferable in two-way fashion
from the first transceiver to the second transceiver. The data is
preferably in digital form and suitable for transfer by electronic
or optical means. A medicament dispenser of this general type is
described in pending UK Patent Application No. 0020538.5.
[0124] The body or housing of the medicament dispenser is typically
shaped to define a cavity within which the medicament container is
receivable. The body and/or medicament container may be further
shaped with any manner of grooves, indentations or other shaping or
surface details to define a `lock and key` relationship between the
body and the container. Colour guides, arrows and any other surface
markings may also be employed.
[0125] One advantage of embodiments of this type is the ability to
store many types of information in different parts of the memory
structure of the transceivers. The information is furthermore
stored in a form which is readily and accurately transferable. The
information could for example, include manufacturing and
distribution compliance information written to the memory at
various points in the manufacturing or distribution process,
thereby providing a detailed and readily accessible product history
of the dispenser. Such product history information may, for
example, be referred to in the event of a product recall. The
compliance information could, for example, include date and time
stamps. The information could also include a unique serial number
stored in encrypted form or in a password protectable part of the
memory which uniquely identifies the product and therefore may
assist in the detection and prevention of counterfeiting. The
information could also include basic product information such as
the nature of the medicament and dosing information, customer
information such as the name of the intended customer, and
distribution information such as the intended product
destination.
[0126] On loading or reloading the dispenser with a medicament
container (such as an aerosol canister or dry powder cassette) the
second transceiver may, for example, read the unique serial number,
batch code and expiry date of the medicament and any other
information on the second transceiver. In this way the nature and
concentration of the medicament, together with the number of doses
used or remaining within the container, may be determined. This
information can be displayed to the patient on a visual display
unit. Other information, such as the number of times the dispenser
has been reloaded with a medicament container, may also be
displayed.
[0127] Similarly, should the container be removed from the housing
before the supply of medicament is exhausted, the same data can be
read from the second transceiver and the number of doses remaining
or used determined. Other information, such as the date and time of
administration of the drug, or environmental exposure data such as
the minimum/maximum temperatures or levels of humidity the
medicament container has been exposed to, may also be read and
displayed to the user.
[0128] In the event that the supply of medicament within the
container becomes exhausted, or that the shelf life of the
medicament has expired, or that the first transceiver does not
recognise the batch code on the second transceiver, activation of
the dispenser may be prevented to safeguard the user. Activation
may also be prevented if the medicament has been exposed to extreme
environmental conditions for periods outwith the manufacturer's
guidelines.
[0129] Data may be transferred to and from any transceiver during
the period of use of the medicament dispenser by the patient. For
example, the medicament dispenser may include an electronic data
management system having various sensors associated therewith. Any
data collected by the sensors or from any data collection system
associated with the electronic data management system including a
clock or other date/time recorder is transferable.
[0130] Data may be transferred each time the patient uses the
device. Or alternatively, data may be stored in a database memory
of the electronic data management system and periodically
downloaded to any transceiver. In either case, a history of the
usage of the device may be built up in the memory of a
transceiver.
[0131] In one embodiment herein, a history of the usage of the
medicament dispenser is transferred to the second transceiver on
the aerosol container. When the medicament container is exhausted
it is exchanged by the patient for a new refill container. At the
point of exchange, which will typically occur at the pharmacy, data
may be transferred from the exhausted container to the refill and
vice-versa. Additionally, usage history data may be read from the
refill and transferred to a healthcare data management system for
example comprising a network computer system under the control of a
healthcare data manager.
[0132] Methods are envisaged herein whereby the patient is given
some sort of reward for returning the refill and making available
the data comprised within the second transceiver. Methods are also
envisaged herein whereby the healthcare data manager is charged for
either receipt of the data from the second transceiver or for its
use for commercial purposes. Any rewards or charging may be
arranged electronically. The methods may be enabled by distributed
or web-based computer network systems in which any collected data
is accessible through a hub on the network. The hub may incorporate
various security features to ensure patient confidentiality and to
allow selective access to information collected dependent upon
level of authorisation. The level of user authorisation may be
allocated primarily to safeguard patient confidentiality. Beyond
this the level of user authorisation may also be allocated on
commercial terms with for example broader access to the database
being authorised in return for larger commercial payments.
[0133] Suitably, the first and second transceiver each comprise an
antenna or equivalent for transmitting or receiving data and
connecting thereto a memory. The memory will typically comprise an
integrated circuit chip. Either transceiver may be configured to
have a memory structure which allows for large amounts of
information to be stored thereon. The memory structure can be
arranged such that parts of the memory are read-only, being
programmed during/after manufacture, other parts are read/write and
further parts are password protectable. Initial transfer of
information (e.g. on manufacture or one dispensing) to or from any
transceiver can be arranged to be readily achievable by the use of
a reader which is remote from the medical dispenser, thereby
minimising the need for direct product handling. In further
aspects, the reader can be arranged to simultaneously read or write
to the memory of multiple transceivers on multiple medicament
dispensers.
[0134] A suitable power source such as a battery, clockwork energy
store, solar cell, fuel cell or kinetics-driven cell will be
provided as required to any electronic component herein. The power
source may be arranged to be rechargeable or reloadable.
[0135] Suitably, data is transferable in two-way fashion between
the first and second transceiver without the need for direct
physical contact therebetween.
[0136] Preferably, data is transferable wirelessly between the
first and second transceiver.
[0137] Suitably, the first transceiver is an active transceiver and
the second transceiver is a passive transceiver. The term active is
used to mean directly powered and the term passive is used to mean
indirectly powered.
[0138] Suitably, the second transceiver comprises a label or tag
comprising an antenna for transmitting or receiving energy; and an
integrated circuit chip connecting with said antenna, and the first
transceiver comprises a reader for said label or tag. In this case
the label or tag is a passive transceiver and the reader is an
active transceiver. Preferably, the reader will not need to be in
direct contact with the tag or label to enable the tag or label to
be read.
[0139] The tag may be used in combination and/or integrated with
other traditional product labelling methods including visual text,
machine-readable text, bar codes and dot codes.
[0140] Suitably, the integrated circuit chip has a read only memory
area, a write only memory area, a read/write memory area or
combinations thereof.
[0141] Suitably, the integrated circuit chip has a one-time
programmable memory area. More preferably, the one-time
programmable memory area contains a unique serial number.
[0142] Suitably, the integrated circuit chip has a preset memory
area containing a factory preset, non-changeable, unique data item.
The preset memory item is most preferably in encrypted form.
[0143] Suitably, the integrated circuit chip has plural memory
areas thereon. Suitably, any memory area is password protected.
[0144] Suitably, any memory area contains data in encrypted form.
Electronic methods of checking identity, error detection and data
transfer may also be employed.
[0145] In one aspect, the integrated circuit has plural memory
areas thereon including a read only memory area containing a unique
serial number, which may for example be embedded at the time of
manufacture; a read/write memory area which can be made read only
once information has been written thereto; and a password protected
memory area containing data in encrypted form which data may be of
anti-counterfeiting utility.
[0146] Suitably, the tag is on a carrier and the carrier is
mountable on the body or housing of the medicament dispenser or the
medicament container.
[0147] In one aspect, the carrier is a flexible label. In another
aspect, the carrier is a rigid disc. In a further aspect, the
carrier is a rectangular block. In a further aspect, the carrier is
a collar ring suitable for mounting to the neck of an aerosol
container. Other shapes of carrier are also envisaged.
[0148] Suitably, the carrier is mouldable or weldable to the
medicament container or housing. Suitably, the carrier encases the
tag. More preferably, the carrier forms a hermetic seal for the
tag.
[0149] In one aspect, the carrier comprises an insulating material
such as a glass material or, a paper material or an organic
polymeric material such as polypropylene. Alternatively, the
carrier comprises a ferrite material.
[0150] The energy may be in any suitable form including ultrasonic,
infrared, radiofrequency, magnetic, optical and laser form. Any
suitable channels may be used to channel the energy including fibre
optic channels.
[0151] In one aspect, the second transceiver comprises a
radiofrequency identifier comprising an antenna for transmitting or
receiving radiofrequency energy; and an integrated circuit chip
connecting with said antenna, and the first transceiver comprises a
reader for said radiofrequency identifier. In this case the
radiofrequency identifier is a passive transceiver and the reader
is an active transceiver. An advantage of radiofrequency identifier
technology is that the reader need not be in direct contact with
the radiofrequency identifier tag or label to be read.
[0152] The radiofrequency identifier can be any known
radiofrequency identifier. Such identifiers are sometimes known as
radiofrequency transponders or radiofrequency identification (RFID)
tags or labels. Suitable radiofrequency identifiers include those
sold by Phillips Semiconductors of the Netherlands under the trade
marks Hitag and Icode, those sold by Amtech Systems Corporation of
the United States of America under the trade mark Intellitag, and
those sold by Texas Instruments of the United States of America
under the trade mark Tagit.
[0153] Suitably, the antenna of the RFID tag is capable of
transmitting or receiving radiofrequency energy having a frequency
of from 100 KHz to 2.5 GHz. Preferred operating frequencies are
selected from 125 KHz, 13.56 MHz and 2.4 GHz.
[0154] In one aspect, the second transceiver comprises a magnetic
label or tag comprising an antenna for transmitting or receiving
magnetic field energy; and an integrated circuit chip connecting
with said antenna, and the first transceiver comprises a reader for
said magnetic label or tag. In this case the magnetic label or tag
is a passive transceiver and the reader is an active
transceiver.
[0155] A suitable magnetic label or tag comprises plural magnetic
elements in mutual association whereby the magnetic elements move
relative to each other in response to an interrogating magnetic
field. A magnetic label or tag of this type is described in U.S.
Pat. No. 4,940,966. Another suitable magnetic label or tag
comprises a magnetorestrictive element which is readable by
application of an interrogating alternating magnetic field in the
presence of a magnetic bias field which results in resonance of the
magnetorestrictive elements at different predetermined frequencies.
A magnetic label of this type is described in PCT Patent
Application No. W092/12402. Another suitable magnetic label or tag
comprising plural discrete magnetically active regions in a linear
array is described in PCT Patent Application No. W096/31790.
Suitable magnetic labels and tags include those making use of
Programmable Magnetic Resonance (PMR) (trade name) technology.
[0156] In another aspect, the second transceiver comprises a
microelectronic memory chip and the first transceiver comprises a
reader for said microelectronic memory chip. The microelectronic
memory chip may comprise an Electrically Erasable Programmable Read
Only Memory (EEPROM) chip or a SIM card-type memory chip. In this
case the microelectronic memory chip is a passive transceiver and
the reader is an active transceiver.
[0157] Any transceiver herein, particularly a passive transceiver
may be mounted on or encased within any suitable inert carrier. The
carrier may comprise a flexible sheet which may in embodiments be
capable of receiving printed text thereon.
[0158] In one aspect, the first transceiver is integral with the
body such that a single unit is comprised. The first transceiver
may for example be encased within or moulded to the body.
[0159] In another aspect, the first transceiver forms part of a
base unit which is reversibly associable with the body. The base
unit may for example, form a module receivable by the body such as
a snap-in module.
[0160] Suitably, the medicament dispenser additionally comprises a
communicator for wireless communication with a network computer
system to enable transfer of data between the network computer
system and the electronic data management system. Dispensers
employing such communicators are described in pending PCT
Applications Nos. PCT/EP00/09291 (PG3786), PCT/EP00/09293 (PG4029)
and PCT/EP00/09292 (PG4159). Preferably, the communicator enables
two-way transfer of data between the network computer system and
the electronic data management system.
[0161] Suitably, the data is communicable between the network
computer system and the electronic data management system in
encrypted form. All suitable methods of encryption or partial
encryption are envisaged. Password protection may also be employed.
Suitably, the communicator employs radiofrequency or optical
signals.
[0162] In one aspect, the communicator communicates via a gateway
to the network computer system. In another aspect, the communicator
includes a network server (e.g. a web server) such that it may
directly communicate with the network.
[0163] In a further aspect, the communicator communicates with the
gateway via a second communications device. Preferably, the second
communications device is a telecommunications device, more
preferably a cellular phone or pager. Preferably, the communicator
communicates with the second communications device using spread
spectrum radiofrequency signals. A suitable spread spectrum
protocol is the Bluetooth (trade mark) standard which employs rapid
(e.g. 1600 times a second) hopping between plural frequencies (e.g.
79 different frequencies). The protocol may further employ multiple
sending of data bits (e.g. sending in triplicate) to reduce
interference.
[0164] In one aspect, the network computer system comprises a
public access network computer system. The Internet is one suitable
example of a public access network computer system, wherein the
point of access thereto can be any suitable entrypoint including an
entrypoint managed by an Internet service provider. The public
access network computer system may also form part of a
telecommunications system, which may itself be either a traditional
copper wire system, a cellular system or an optical network.
[0165] In another aspect, the network computer system comprises a
private access network computer system. The private access network
system may for example, comprise an Intranet or Extranet which may
for example, be maintained by a health service provider or
medicament manufacturer. The network may for example include
password protection; a firewall; and suitable encryption means.
[0166] Preferably, the communicator enables communication with a
user-specific network address in the network computer system.
[0167] The user-specific network address may be selected from the
group consisting of a web-site address, an e-mail address and a
file transfer protocol address. Preferably, the user-specific
network address is accessible to a remote information source such
that information from said remote information source can be made
available thereto. More preferably, information from the
user-specific network address can be made available to the remote
information source.
[0168] In one aspect, the remote information source is a medicament
prescriber, for example a doctor's practice. Information
transferred from the medicament prescriber may thus, comprise
changes to prescription details, automatic prescription updates or
training information. Information transferred to the medicament
prescriber may comprise compliance information, that is to say
information relating to the patient's compliance with a set
prescribing programme. Patient performance information relating for
example, to patient-collected diagnostic data may also be
transferred to the medicament prescriber. Where the dispenser is an
inhaler for dispensing medicament for the relief of respiratory
disorders examples of such diagnostic data would include breath
cycle data or peak flow data.
[0169] In another aspect, the remote information source is a
pharmacy. Information transferred from the pharmacy may thus,
comprise information relating to the medicament product.
Information sent to the pharmacy may thus include prescription
requests which have been remotely pre-authorised by the medicament
prescriber.
[0170] In a further aspect, the remote information source is an
emergency assistance provider, for example a hospital accident and
emergency service or an emergency helpline or switchboard. The
information may thus, comprise a distress or emergency assist
signal which requests emergency assistance.
[0171] In a further aspect, the remote information source is a
manufacturer of medicament or medicament delivery systems.
Information transferred to the system may thus, comprise product
update information. The system may also be configured to feed
information back to the manufacturer relating to system
performance.
[0172] In a further aspect, the remote information source is a
research establishment. In a clinical trial situation, information
may thus be transferred relating to the trial protocol and
information relating to patient compliance fed back to the research
establishment.
[0173] In a further aspect, the remote information source is an
environmental monitoring station. Information relating to weather,
pollen counts and pollution levels may thus be made accessible to
the system.
[0174] In a further aspect, the remote information source is a
computer software download site from which software may be
downloaded for use in the electronic data management system.
Embodiments are envisaged in which such software downloads are
employed to upgrade or modify any existing software employed by the
electronic data management system.
[0175] Suitably, the medicament dispenser additionally comprises a
geographic positioning system such as a global positioning system
or a system which relies on the use of multiple communications
signals and a triangulation algorithm.
[0176] In another embodiment, the inhaler additionally comprises
climate control means. Preferably, the climate control means is
actuable by the coupling.
[0177] The climate control means may comprise means to (i) reduce
moisture increase in the dispenser; and/or (ii) maintain ambient
temperature; and/or (iii) dry the meter prior to actuation of the
dispenser.
[0178] The climate control means may comprise a desiccant and/or a
heater.
[0179] The climate control means may comprise a temperature and/or
a moisture sensor.
[0180] The dispenser of the invention is suitable for dispensing
medicament, particularly for the treatment of respiratory disorders
such as asthma and chronic obstructive pulmonary disease
(COPD).
[0181] 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.
[0182] 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
antiinflammatory steroid such as a beclomethasone ester (e.g., the
dipropionate) or a fluticasone ester (e.g., the propionate). A
particularly preferred combination comprises salmeterol xinafoate
salt and fluticasone propionate.
[0183] Preferred medicaments are selected from albuterol,
salmeterol, fluticasone propionate and beclomethasone dipropionate
and salts or solvates thereof, e.g., the sulphate of albuterol and
the xinafoate of salmeterol, and any mixtures thereof.
Alternatively, the dispenser may be employed for dispensing
vaccine.
[0184] The medicament container may comprise medicament in dry
powder form. Typically, a dry powder medicament includes a
pharmaceutical excipient in dry powder form.
[0185] In one embodiment, the density of the dry powder medicament
particles is reduced relative to standard dry powder
medicament.
[0186] In another embodiment, the dry powder medicament particles
are aerodynamically shaped to improve medicament delivery to the
patient.
[0187] In another embodiment, the medicament container may comprise
medicament in solution or suspension form.
[0188] The medicament container may comprise a suspension of a
medicament in a propellant, for example, liquefied HFA134a,
HFA-227, helium or carbon dioxide.
[0189] Alternatively, the medicament container may comprise a
solution of a medicament in a solvent.
[0190] Preferably, the medicament dispenser additionally comprises
a safety mechanism to prevent unintended multiple actuations of the
dispenser.
[0191] The safety mechanism may impose a time delay between
successive actuation of the dispenser.
[0192] Preferably, the medicament dispenser comprises a manual
override enabling manual actuation of the trigger means. The manual
override may be designed to cover all situations in which the
coupling does not actuate in the normal manner. These will include
situations where actuation does not happen (e.g. due to power
failure). Alternatively, this will include situations where
actuation occurs, but reset of the coupling fails (e.g. due to
power being in "continuous on" mode) and a manual reset, decoupling
(e.g. by severing the coupling) or "circuit break" is employed.
[0193] Preferably, the medicament dispenser comprises a child
resistance feature to prevent undesirable actuation thereof by
children.
[0194] In another aspect, the invention provides an actuator for
use in a medicament dispenser as described hereinabove.
[0195] In a further aspect, the invention provides an actuator for
a medicament container comprising a housing, dose-liberating means,
an energy store for actuating said dose-liberating means, within
said housing, a container seat for receipt of the medicament
container; on the housing or connecting therewith, trigger means to
release the energy store, wherein the trigger means comprises a
trigger coupling which is reversibly deformable in response to the
application of non-mechanical energy thereto.
[0196] The actuator herein may be configured to include, as
relevant, any of the above described features of the medicament
dispenser. In particular, the actuator may be configured to include
an electronic data management system comprising control means for
the actuation of the coupling.
[0197] Preferably, the non-mechanical energy comprises electric
current flow through the coupling.
[0198] In one embodiment, the coupling comprises one or more wires
which contract in response to application of non-mechanical energy
thereto. More preferably, the one or more wires comprise an alloy
which undergoes a phase transition on heating, for example in
response to flow of electrical current therethrough. The alloy is
for example, a nickel-titanium alloy.
[0199] In another embodiment, the one or more wires comprise an
alloy which undergoes a phase transition on application of a
magnetic field thereto (magnetic shape memory alloys).
[0200] Suitably, the actuator additionally comprises an electronic
control system for controlling the supply of non-mechanical energy
to the coupling. Suitably, the electronic control system is capable
of providing pulses of non-mechanical energy to the coupling.
[0201] Suitably, the electronic control system is capable of
receiving inputs from electronic sensors locatable on the
dispenser. Suitably, the actuator additionally comprises an
electronic sensor selected from the group consisting of a breath
sensor, a shake sensor, a temperature sensor, an infrared sensor
and a patient ID sensor.
[0202] In a further aspect, the invention provides a medicament
container for use in the dispenser and/or the actuator as described
hereinabove.
[0203] According to a further aspect of the present invention there
is provided a laboratory test apparatus comprising at least one
actuator as described above and a mounting (e.g. a bench mounting)
for the at least one actuator. The laboratory test apparatus is
designed for use in testing the performance of the medicament
dispenser in a laboratory environment. Often, plural actuators will
be mounted on a single mounting to enable simultaneous testing
thereof. The laboratory test apparatus will typically be connected
to various sensors and recording devices for monitoring aspects of
the performance of the medicament dispenser.
[0204] According to a further aspect of the present invention there
is provided a kit of parts comprising a medicament dispenser as
described above in the form of a cartridge; and a housing shaped
for receipt of said cartridge.
[0205] According to a further aspect of the present invention there
is provided a kit of parts comprising an actuator as described
above and, receivable by said actuator, a medicament container.
[0206] In a preferred commercial embodiment herein, the actuator is
arranged for receipt of a refill cartridge. Typically, the actuator
is in the form of a relatively complex device, including for
example an electronic data management system and the cartridge is
in the form of a medicament refill therefor.
[0207] In another aspect the cartridge comprises a medicament
dispenser having a voltaic cell as an electrical energy source and
the housing is provided with a mouthpiece for patient inhalation
therethrough and electronic information display apparatus for
displaying information to the patient.
[0208] The invention will now be described further with reference
to the accompanying figures in which:
[0209] FIG. 1a shows an inhaler in accordance with one embodiment
of the invention in a rest position;
[0210] FIG. 1b shows the inhaler of FIG. 1a in a primed
position;
[0211] FIG. 1c shows the inhaler of FIGS. 1a and 1b in a firing
position; and
[0212] FIG. 1d shows the inhaler of FIGS. 1a to 1c whilst
resetting.
[0213] Referring now to the figures, FIGS. 1a to d schematically
represent a breath operated metered dose inhaler 2. The inhaler
comprises a canister 4 containing a suspension of medicament in a
pressurised propellant such as p134a. The canister is linked at it
base to a valve 6. Relative movement of the canister 4 with respect
to the valve 6 results in a metered dose of medicament being
dispensed to the patient. A mouthpiece 8 protrudes from the inhaler
for passage of the medicament to the patient.
[0214] At rest (as shown in FIG. 1a) the canister 4 is retained in
a non-dispensing position by a firing lever 10 pivotally mounted at
fulcrum 12 and locked in position by firing cam lock 16. Firing
lever 10 is pivotally linked at 18 to a tension spring 20 which is
connected to a priming lever 22 and pivotally linked at its other
end 24 to the canister 4. The tension spring 20 acts as an energy
store for actuating the firing mechanism of the inhaler as
described infra.
[0215] To prime the device for dispensing a patient depresses the
priming lever 22 (see FIG. 1b). This induces a tension in the
tension spring 20 as the spring is extended. The priming lever 22
is locked into the priming position by priming cam lock 26.
[0216] As the patient inhales, a breath sensor (not shown)
registers the patient's breath, completes an electrical circuit
(not shown), the current from which heats a trigger coupling or in
this case, a firing shape memory alloy (SMA) wire 28 which is
linked to the firing cam lock 16. As the SMA wire 28 increases in
temperature it contracts, and in doing so removes the firing cam
lock 16 from the firing lever 10. The tension spring 20 now
releases its energy and recoils upwards and pivots the firing lever
10 downwards thus pulling the canister 4 down relative to the valve
6 to release a dose of medicament through the mouthpiece 8 of the
inhaler.
[0217] A reset means is shown in FIG. 1d. The advantages of having
a positive reset mechanism are numerous. In devices where there is
no reset mechanism it is possible for the canister to stick in the
firing position. This may effect the efficacy of further inhaler
actuations as well as dosing efficacy and can result in medicament
leakage. Furthermore, the longer the canister remains in the firing
position, the increased likelihood of medicament deposition and/or
increased medicament concentration in the lower parts of the
canister. A positive reset mechanism is therefore technically
advantageous in addition to increasing consumer confidence and ease
of use of the device.
[0218] There may be either a separate reset button linked to the
reset means or the reset means may be actuated after a
predetermined time delay post firing of the inhaler. Once actuated,
a reset SMA wire 30 heats and contracts pulling a reset cam lock 32
down and releasing the priming lever 22. As the priming lever 22
returns to its rest position as illustrated in FIG. 1a, the firing
lever 10 is returned to its rest position via the tension spring
20. The firing lever 10 is then relocked in its rest position by
the firing cam lock 16.
[0219] It may be appreciated that any of the parts of the inhaler
or actuator which contact the medicament suspension may be coated
with materials such as fluoropolymer materials which reduce the
tendency of medicament to adhere thereto. 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.
[0220] 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.
[0221] 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:
* * * * *
References