Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO 95/04562 PCT/US94/08487
1
RELOADABhE INJECTOR
$ACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to an apparatus for
injecting medicaments and to improvements in
apparatus suitable for effecting multiple
injections.
Automatic injectors are well known.
Basically, an automatic injector is a device for
enabling an individual to self-administer a dosage
of a liquid medicament. An advantage of automatic
injectors is that they contain a measured dosage of
a liquid medicament in a sealed, sterile condition
capable of storage in such condition for an
extensive period of non-use, during which period
immediate injection of the stored dosage may be
accomplished at any time under the most severe
emergency conditions. Another advantage of
automatic injectors is~that the administration of
the self-contained dosage of liquid medicament is
accomplished without the necessity of the user
initially seeing the hypodermic needle through which
the medicament is injected or of manually
penetrating such a visible needle into the user s
own tissue. Instead, an automatic injector includes
a releasable stressed spring assembly. This
assembly includes a stressed spring, a releasable
mechanism for releasably retaining the spring in a
stressed storage position and a releasing mechanism
for releasing the releasable mechanism in response
to a predetermined actuating procedure.
Automatic injectors have heretofore been
particularly suited for use under emergency
WO 95104562 PCT/US94/08487
2
situations. For example, many tens of millions of
such automatic injectors have been manufactured and '
sold containing nerve gas antidotes for use under
emergency chemical warfare conditions. Typical
units which have been utilized for this purpose are
disclosed in U.S. Patent Nos. 2,832,339, 3,882,863,
and 4,031,893. In addition, units of this type have
been proposed for use in administering
antiarrhythmic medicaments under emergency
conditions relating to heart attack medical
situations. Such use has been in conjunction with
portable monitors as is evident from the disclosure
contained in U.S. Patent Nos. 3,910,260 and
4,004,577. It has also been proposed to provide
other medicaments useful in treating heart attack
symptoms, such as clot selective thrombolytic agents
(e. g., tPA) and related medicaments. Finally,
automatic injectors have been marketed in recent
years containing a dosage of epinephrine as an
antidote for counteracting severe allergic
reactions, as for example, bee stings and the like.
In all of these instances, the emergency
use aspect of the automatic injectors is of primary
significance.
SUNIMA~tY OF THE INVENTION
The present invention stems from the
recognition that the advantages of automatic
injectors are not limited only to emergency
situations, but that there are many other medicinal
administration situations requiring a much more
frequent usage where the painlessness and simplicity
of actuation of an automatic injector combined with
other conveniences, would be sufficiently desirable
WO 95/04562 ~ ~ PCT/US94/08487
~g~'~~
3
to many individuals to warrant the added costs in
comparison to the more simple and less costly manual
syringes in widespread use. For example, recently
the drug erythropoietin has been approved by the FDA
in combating anemia. The drug is particularly
useful to kidney patients, AIDS patients, and
patients donating blood for their own use in
anticipation of elective surgery. Such patients may
have need for the administration of erythropoietin
as frequently as once a week. An automatic injector
provides a very convenient way of allowing the
patient to administer the necessary erythropoietin
without requiring the patient to become proficient
in inserting a needle into his own flesh. Under
circumstances of this type, it is desirable to
provide the user with maximum convenience in
availability, handling and use of the automatic
injector, while doing so by the. least expensive
means possible.
To accomplish this objective, there have
been a number of automatic injectors which provide a
reusable power pack to effectuate an injection of a
medicament containing cartridge. By providing such
a reloadable power pack, the user is able to save
expenses in that the same firing mechanism can be
used several times rather than being discarded after
each injection. Such a reusable power pack has been
disclosed in U.S. Patent No. 2,752,918. However, in
this patent, the injection needle formulates part of
the power pack assembly, and must therefore be
cleaned after each and every use to prevent
contamination thereof. In U.S. Patent No.
3,403,679, there is proposed an automatic injector
which provides a reloadable injector which is
capable of reloading a medicament cartridge
WO 95/04562 PCT/LTS94I08487
4
containing a charge of medicament and a needle
disposed therein. The problem associated with this
type of injector is that after an injection, an
exposed needle must be discarded before replacing a
fresh cartridge within the power pack. Such exposed
needles often contain traces of blood, which may
become the source of transmittable disease.
Therefore, great care and expense must be taken when
the cartridge of such an injector is disposed. The
same sort of problem is presented in our earlier
U.S. Patent No. 4,518,384. In that patent, there is
disclosed several embodiments of a reloadable firing
mechanism which is cooperable with an expendable
medicament containing clip. The clip disclosed in
this patent contains several medicament/needle
cartridges which are successively ejected from the
clip housing after each injection. In those
cartridges, the needle must be discarded without the
benefit of an outer rigid protective housing to
prevent an unwary individual from accidently
pricking himself with the expended needle. In
addition, this device is rather bulky and is not
suited for a user to carry on his or her person, for
example in the individual's pocket.
In U.S. Patent No. 5,137,516, there is
also disclosed a reloadable injector. However, as
disclosed in that patent, after an injection
operation, the needle is left in an extended
position, and it is necessary to place an endcap
over the exposed needle to cover the same before
disposal. Since the user must br'~ng the endcap
towards the needle and place it thereover, the user
risks self-pricking when covering the needle. In
another embodiment of this patent, the user must
place the exposed needle into a relatively large and
WO 95/04562 ~ PCT/US94/08487
expensive compartment while the needle is still
' secured to the power pack assembly. Additionally,
in both of the aforementioned embodiments, the outer
covering is separately provided rather than
5 integrally formed with the injector and may be lost
or misplaced during an injection procedure.
It is an object of the present invention
to resolve the problems stated above. This object
is accomplished by providing a reloadable, automatic
injector comprising a reusable power pack assembly
for effectuating multiple injection operations. The
power pack assembly includes an outer body and an
energy releasing assembly disposed within the body.
The energy releasing assembly is capable of
providing multiple energy releasing strokes. A
disposable cartridge assembly is provided which is
engageable with the power pack assembly and forms an
elongate injection assembly therewith. The
cartridge assembly is adapted to receive energy from
the power pack during one of the energy releasing
strokes. A charge of medicament is disposed within
the housing, and a needle is held in a normally
protected position within the housing. A plunger is
disposed within the housing for forcing the
medicament through the needle. The cartridge
assembly receives energy from the power pack
assembly during one of the energy releasing strokes
to enable the needle to project form the protected
position to an unprotected projecting position from
the housing and to enable the plunger to force the
medicament through the needle. In addition, a
. needle return means is provided for returning the
needle from the unprotected position to the
protected position within the housing so that the
housing provides the needle with a rigid protective
WO 95/04562 ~~ ~ ~ PCT/LTS94/08487
6
outer covering for sanitary disposal of the
cartridge assembly.
It is another object of the present
invention to provide a disposable cartridge for a
reloadable automatic injector assembly comprising a
rigid housing which is adapted to be engaged with a
power pack assembly capable of effectuating an
injection. A single charge of medicament and a
needle are both contained within the housing. In
addition, a plunger is disposed within the housing
for forcing the medicament through the needle. The
cartridge assembly is adapted to receive an energy
releasing stroke from the power pack assembly to
enable the needle to project from the protected
position to an unprotected projecting position from
the housing and to enable the plunger to force the
medicament through the needle. In addition, a
needle return spring is provided in order to return
the needle to the protected position within the
housing from the unprotected projecting position so
that the housing provides the needle with a rigid
protective outer cover for sanitary disposal of the
cartridge.
It can be seen ~-.3t the present invention
allows a needle containing cartridge to be
disengaged from a power pack assembly after an
injection operation. The needle return spring
within the cartridge assembly automatically returns
the needle into the rigid outer housing of the
cartridge so that the cartridge provides a self-
contained protective covering for the used needle.
Upon disposal, there is no chance of an unwary
individual to.accidently prick himself with the used
needle. In addition, the needle return spring
allows the needle to be protected without the need
WO 95/04562 ~ ~ PCT/LTS94/08487
7
for an auxiliary cap to be placed thereover. Thus,
there is no cap to be lost and there is no manual
movement of a cap towards an exposed needle to cover
the same. Finally, it can be appreciated that the
narrow elongate shape of the injection assembly
allows the device to be easily transported by the
user.
These and other objects of the present
invention will become more apparent during the
course of the following detailed description and
appended claims. The invention may be best
understood with reference to the accompanying
drawings wherein illustrative embodiments are shown.
$RIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a longitudinal sectional view
of one embodiment of an automatic injector,
embodying the principles of the present invention,
which shows a power pack and cartridge assembly
disengaged from one another.
Figure 2 is a longitudinal sectional view
of the embodiment of Figure 1 after the power pack
and cartridge assembly have been engaged with one
another.
Figure 3 is a longitudinal sectional view
of the embodiment of Figures 1 and 2 after the
injector has been activated.
Figure 4 is a longitudinal sectional view
of a second embodiment of an automatic injector
embodying the principles of the present invention.
WO 95/04562 PCT/US94/08487
8
DEmaTr.Fn nF~c~RTI~TTON OF THE DRAWINGS
Turning now to Figure 1, there is shown a
reloadable automatic injector generally indicated at
10. The injector includes a power pack assembly 12
and a cartridge assembly 14.
The power pack assembly 12 is reusable in
that it may be repeatedly cocked and fired to
provide multiple energy releasing strokes and is
successively engageable with a number of cartridge
assemblies 14 to effectuate the same number of
injection operations on which a medicament is
injected into the flesh of a patient.
Power pack assembly 12 has a body 16 and
an energy releasing assembly disposed therein. The
energy releasing assembly includes a power spring
18, which can be compressed and then released to
provide energy for the energy releasing strokes.
Body 16 is substantially in tubular form,
and has an inner surface 20. At about the mid-point
of tubular body 16, an annular ring portion 22
extends inwardly toward a longitudinal axis of body
16 from inner surface 20. Annular ring portion 22
divides the body into forward and rearward portions
and has a rearwardly facing surface 24.
Disposed within body 16 is a
concentrically disposed release pin assembly 26.
Release pin assembly 26 has a substantially tubular
shape and has an outer surface which is held in a
slidable relation with a surface comprising the
inner peripheral circumference of annular ring
portion 22. Release pin assembly 26 has an
outwardly extending annular portion 28 which has a
slightly greater diameter at the rearward end
thereof. Annular portion 28 has a forwardly facing
WO 95104562 ' PCT/US94108487
9
surface 30 which is engageable with the rearwardly
- facing surface 24 of annular ring portion 22 to
limit the forward movement of release pin assembly
- 26 with respect to body 16.
While the greater portion of release pin
assembly 26 comprises a tubular sleeve-like portion
32, the forward portion 38 of the release pin
assembly has a substantially cylindrical shape with
forward and rearward circular ends 34 and 36,
respectively.
Forward portion 38 of release pin assembly
26 has at its outer periphery release pin balls 40
protruding radially outwardly therefrom. The
release pin balls are substantially spherical in
form, but have only a portion thereof protruding
from the forward portion 38. The balls 40 are held
in protruding relation by a central pin 41, as best
seen in Figure 2, disposed within forward portion
38. Central pin 41 has a large diameter portion 43
and a narrowed diameter portion 45. The exterior
surface of the large diameter portion 43 is normally
in engagement with balls 40 so as to keep them
protruding from forward portion 38. Central pin 41
is forwardly moveable against the biasing action of
coil spring 49, by operation of operating rod 54, so
that narrowed diameter portion 45 is in radial
alignment with balls 40 so as to allow balls 40 to
move inwardly into forward portion 38.
Pin 41 has a rearward end thereof
- 30 extending from the circular end 36 of forward
portion 38 rearwardly into sleeve-like member 32
- towards the rearward end of power pack assembly 12.
Referring back to Figure 1, it can be seen
that body 16 has a forward annular ridge 42 formed
WO 95/04562 ~ PCT/US94/08487
..
on the exterior periphery thereof in rearwardly
spaced relation to the forward end thereof and a '
rearward ridge 44 of sightly lesser exterior
diameter disposed in rearwardly spaced relation with
5 respect to the forward ridge 42. A rearward end
portion 46 has a somewhat tube-like shape which is
adapted to receive therein the rearward portion of
body 16. End portion 46 has along its interior
periphery an annular groove 48 which is adapted to
10 receive rearward annular ridge 44, which allows end
portion 46 to be retained at the rearward end of
body 16.
End portion 46 has a central recessed
portion 50 with a central hole 52 therethrough.
Hole 52 provides a passage for an operating rod 54,
which extends from an exterior position of end
portion 46 through hole 52 and into the inner
confines of power spring 18 at the rearward end
thereof .
The rearward end of operating rod 54,
which extends rearwardly from end portion 46, is
provided with a manually engageable pushbutton 56
having a narrow forward portion 58 which can be
received into recessed portion 50 of end portion 46,
and a rearward portion 60 having an enlarged
diameter which cannot be received into recessed
portion 50.
Recessed portion 50 has an annular
inturned portion 62 which forwardly provides a seat
for thrust washer 63 and rearwardly provides a -
forward seat for a compression spring member 64
which biases pushbutton 56 outwardly away from end
portion 46.
As shown, a flip-top cap 66 is provided to
cover pushbutton 56 so as to prevent an accidental
WO 95/04362 PCT/US94/08487
t
11
actuation of the unit. Flexible hinge element 68 is
provided to allow flip-top cap 66 to pivot with
respect to end portion 46.
At the forward portion of power pack
assembly 12, inner surface 20 is provided with
receiving threads 70 which are capable of receiving
threads 72 disposed on the exterior surface 74 of
tubular cartridge assembly 14, which will now be
described in greater detail.
While cartridge assembly 14 is of a
substantially tubular shape, the forward portion 76
thereof has a slightly greater diameter than the
rearward portion 78 thereof. At the transition
between the rearward and forward portions 78 and 76,
respectively, there is a rearwardly facing annular
surface 80, which is adapted to engage the forward
annular surface 82 of body 16 when the cartridge
assembly 14 is secured to power pack assembly 12.
Disposed within container or cartridge
assembly 14 is a cartridge 84 which is held in a
slidable relation with equally spaced interior ribs
86 formed on the inner surface 87 of a rigid housing
generally indicated at 88. Cartridge 84 is
preferably made of glass, and contains a liquid
medicament 90 therein. The cartridge 84 is open at
its rearward end and necked down at its forward end
to receive a hub assembly 92. A plunger 94 closes
the open rearward end of the cartridge 84 and is
mounted therein for forward sliding movement in
sealed relation with the interior of the cartridge
84. Plunger 94 has an elongate plunger rod 95
extending in a rearward direction therefrom. The
function of plunger rod 95 will be described in
conjunction with Figures 2 and 3. The hub assembly
92 has fixed to the forward end thereof the rearward
CA 02168670 2004-10-04
12
end of a hypodermic needle 96 which extends
forwardly therefrom. The hypodermic needle 96 is
incased with a resilient sheath 98 which extends
forwardly from the crimped forward portion of hub
assembly 92. Preferably, as shown, the hub assembly
92 is of the type which includes a burstable seal
100 in the rearward portion thereof, such as
disclosed in U.S. Patent Nos. 3,380,449 and
3,391,695. The seal 100 of the hub assembly 92
serves to sealingly confine the liquid medicament 90
within the cartridge 84 at its forward end, with the
plunger 94 confining it at its rearward end.
The forward end of rigid housing 88 is
provided with an annular groove 102 which is adapted
to receive an annular ridge 104 of a forward cap
member 106. Cap member 106 has a central hole 108
which is large enough to permit needle 96 to project
therethrough while small enough to prevent sheath 98
from doing the same. An annular guide 110 surrounds
hole 108 and bears against sheath 98 and operates to
maintain needle 96 in alignment with hole 108. Cap
member 106 has a flat annular surface 112 at its
innermost extremity with respect to housing 88.
Surface 112 provides a bearing surface for a return
spring 114 which is disposed between surface 112 and
a portion of hub assembly 92. In Figure 1, all three
springs 64, 18, and 114 are shown in a relaxed
condition.
In Figure 2, there is shown the reloadable
automatic injector 10 in assembled condition wherein
the cartridge assembly 14 is engaged with power pack
assembly 12. As described above, this engagement is
accomplished by cooperably screwing threads 72 of
WO 95/04562 ~ ~ PCT/US94/08487
13
tubular cartridge 14 in a clockwise direction with
respect to threads 70 of power pack assembly 12.
As the two assemblies 12 and 14 are
screwed together, a leading surface 116 of cartridge
assembly 14 is biased against the release pin balls
40 so as to move the entire release pin assembly
rearwardly therewith. As the release pin assembly
26 is moved rearwardly, power spring 18 is
compressed between circular end 36 of forward
portion 38 and a forwardly facing surface of thrust
washer 63.
Cartridge assembly 14 is continuously
screwed into power pack assembly l2 until the
annular surface 80 of the cartridge assembly 14
meets the forward annular surface 82 of power pack
assembly 12 which prevents further screwing. When
the screwing action is complete, balls 40 are left
only a slight distance from annular ring portion 22
of body 16, and the forward end 118 of operating rod
54 is left only a slight distance from the rearward
end of central pin 41, which extends rearwardly from
circular end 36. It can be appreciated that the
screwing action operates to. cock or reload the power
spring 18 to prepare it for an energy releasing
stroke.
The actuation of the reloadable automatic
injector 10 is described in conjunction with Figures
2 and 3. There, it can be seen that before the
injector can be actuated, flip-top cap must be
pivoted on hinge 68 to permit access to activating
pushbutton 56. When exposed, pushbutton 56 may be
manually engaged and moved forward so that the
forward end 118 of operating rod 54 comes into
contact with the rearward end of pin 41.
WO 95/04562 PCT/US94/08487
. ~;
14
It can be seen that, as pushbutton 56 is
moved inwardly toward body 16, the narrow portion 58
is permitted to enter recess 50 of end portion 46 as
compression spring member 64 is compressed
therebetween. It can be appreciated that pushbutton
56 may be pressed only a slight distance before
compression spring member 64 becomes fully
compressed such that pushbutton 56 can no longer
move forward. However, the slight distance which
operating rod 54 is moved forwardly within power
pack assembly 12 is enough for it to engage and move
pin 41 forwardly so that release pin balls 40 can
ride into narrowed diameter portion 45 of pin 41.
As a result, the balls 40 can ride over leading
surface 116 of cartridge assembly 14. Once the
outer periphery of release pin balls 40 become flush
with the exterior surface of forward portion 38, the
release pin assembly 26 becomes free to slidably
move within rearward portion 78 of cartridge
assembly 14 towards the forward end of the injector.
As release pin assembly 26 is accelerated
towards the forward end of the reloadable automatic
injector 10 by power spring 18, the forward circular
end 34 thereof is forced against the rearward end of
plunger rod 95. This action, in turn, forces the
entire cartridge 84 towards the forward cap member
106. This, in turn, causes spring 114 to become
compressed, as needle 96 pierces through sheath 98
and the needle exits the rigid housing through the
hole 108 in cap member 106. In this forward motion -
of the cartridge and needle, the sheath 98 and
spring 114 operate as shock absorbers to prevent .
breakage of glass cartridge 84.
After cartridge 84 reaches its forwardmost
position in rigid housing 88, the release pin
WO 95/04562 PCT/US94/08487
assembly 26 continues its forward motion so that
forward circular end 34 biases plunger rod 95 and
plunger 94 forwardly with respect to cartridge 84,
thereby compressing medicament 90 to the extent that
5 burstable seal 100 is ruptured and medicament is
permitted to enter the rearward end and through
needle 96 to be injected into a patient.
The forwardly facing surface 30 of annular
portion 28 of release pin assembly 26 finally
10 reaches the rearwardly facing surface 24 of annular
ring portion 22, which stops further forward motion
of release pin assembly 26.
As shown in Figure 3, the needle 96 is
held in an extended position after an injection
15 operation. After such operation, the entire
reloadable injector 10 is moved away from the
patient so that the needle is withdrawn from the
flesh of the patient.
The disengagement of cartridge assembly 14
from power pack assembly 12 will now be described.
Simply, cartridge assembly 14 is rotated in a
counterclockwise direction with respect to power
pack assembly 12 until it is completely disengaged
therefrom. As the cartridge assembly 14 is
unscrewed from power pack assembly 12, the spring
114 urges cartridge 84 away from cap member 106 to
thereby return needle 96 into rigid housing 88.
After complete disengagement, the power pack
assembly is substantially in the same condition as
shown in Figure 1 and is ready to receive a new
cartridge assembly. Coil spring 49 urges central
= pin 41 rearwardly so that large diameter portion 43
is once again aligned with balls 40, which once
again project from forward portion 38.
WO 95/04562 ~ ~ PCTIUS94/08487 ~ ,
16
The used cartridge assembly 14, on the
other hand, ends up in substantially the same
condition as shown in Figure 1, with the exception
of the fact that plunger 94 and plunger rod 95 are
forwardly disposed relative to the cartridge 84, and
medicament 90 is no longer contained within the
cartridge. However, as shown in Figure 1, the
needle is held in a sheathed position within rigid
housing 88 and can be readily disposed without the
possibility of the needle projecting therefrom and
accidentally injuring an unwary individual. It
should be noted, that since the needle is returned
within rigid housing 88, no additional cap is needed
to cover the same. The advantage of this has been
described hereinbefore.
In Figure 4, there is shown another
embodiment of the present invention. In Figure 4,
elements which are similar to those in Figures 1, 2
and 3 have been designated with the same numerals.
Figure 4 shows the injector in an
assembled condition wherein cartridge assembly 14 is
engaged with power pack assembly 12. The injector
in Figure 4 operates in substantially the same
manner as in the previous embodiment except that the
cartridge assembly 14 is engaged with power pack
assembly 12 with a conventional quarter turn
attachment generally indicated at 150. In addition,
rather than providing an operating rod 54 and pin
41, a single operating rod 152 is provided which
includes a decreased diameter portion 154.
Operating rod 152 operates to maintain balls 40 in
an outwardly projected position from release pin
assembly 156. The injector is provided with a
rearward cap 158 which has a pocket clip 160 secured
thereto. When cap 158 is removed, access to
WO 95/04562 PCT/LTS94/08487
17
pushbutton 56 is made possible. When pushbutton 56
is manually actuated, compression spring member 64
is compressed and operating rod 152 is moved
forwardly within release pin assembly 156 so that
decreased diameter portion 154 is moved forwardly
and permits balls 40 to retract therein. As a
result, the forward end 164 (having an enlarged
diameter) of sleeve 165 is permitted to ride over
the withdrawn balls and, in cooperation with~power
spring 18, force rearwardly facing annular surface
168 of sleeve-like piston member 166 forwardly so
that the forward end 170 of piston member 166 drives
into plunger 94 to project the needle and then
dispense medicament 90. After use, the cartridge
assembly 14 can be disengaged from power pack
assembly 12, at which time spring 114 operates to
retract needle 96 into rigid outer covering 88 to
provide the needle with a sanitary rigid outer
covering for disposal.
In this embodiment, it can be appreciated
that after an injection operation, the piston member
166 remains projecting from body 16 of power pack
assembly 12 in a forward direction therefrom. In
this embodiment, the engagement of cartridge
assembly 14 with power pack assembly 12 does not
accomplish the proper reloading of the power pack
assembly. In other words, the engagement will not
effectuate a recocking or compression of power
spring 18. Rather, piston member 166 must be
manually pushed back into body 16 by grasping the
body with one hand and biasing the forward end of
piston member 166 against a table or other rigid
surface until the spring is held in a compressed
position by balls 40.
WO 95/04562 PCT/US94/08487
18
It thus will be seen that the objects of
this invention have been fully and effectively
accomplished. It will be realized, however, that
the foregoing preferred specific embodiments have
been shown and described for the purpose of this
invention and are subject to change without
departure from such principles. Therefore, this
invention includes all modifications encompassed
with the spirit and scope of the following claims.
