U.S. patent application number 09/045314 was filed with the patent office on 2001-09-06 for injection system.
Invention is credited to KLITMOSE, LARS PETER, LARSEN, ANDRE, MIKKELSEN, SOREN.
Application Number | 20010020155 09/045314 |
Document ID | / |
Family ID | 26063815 |
Filed Date | 2001-09-06 |
United States Patent
Application |
20010020155 |
Kind Code |
A1 |
MIKKELSEN, SOREN ; et
al. |
September 6, 2001 |
INJECTION SYSTEM
Abstract
An injection system for preparing a mixture of a solvent and a
medicament and for subsequent dosed injection of the mixture
comprises a syringe accommodating an ampoule (7) in which a liquid
is stored between a membrane (8) closing one end of the ampoule (7)
and a piston (6) which can by a piston rod (3) be forced into the
ampoule (7) to press out a dose of the liquid. The piston rod (3)
and the piston (6) has mutual engaging threads (4, 5) by which said
piston (6) is coupled to the piston rod (3) to follow this rod in
both axial directions. An outer thread (30) engaging an inner
thread (29) in a housing is provided on a part (28) of the piston
rod (3) so that rotation of the piston rod (3) will screw this rod
and the piston (6) into the ampoule (7). A detent (18) ensures that
the piston rod (3) is only rotated in a dose administering
direction. However, the thread (30) of the piston rod (3) can be
disengaged from the thread (29) of the housing to set the piston
rod (3) free to be moved in a proximal direction.
Inventors: |
MIKKELSEN, SOREN; (BALLERUP,
DK) ; KLITMOSE, LARS PETER; (GENTOFTE, DK) ;
LARSEN, ANDRE; (DRAGOR, DK) |
Correspondence
Address: |
STEVEN T ZELSON
NOVO NORDISK OF NORTH AMERICA INC
405 LEXINGTON AVE
SUITE 6400
NEW YORK
NY
101746401
|
Family ID: |
26063815 |
Appl. No.: |
09/045314 |
Filed: |
March 20, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60047930 |
May 30, 1997 |
|
|
|
Current U.S.
Class: |
604/187 |
Current CPC
Class: |
A61M 5/24 20130101; A61M
5/3156 20130101; A61J 1/2096 20130101; A61M 5/31586 20130101; A61M
2005/2411 20130101; A61M 2205/582 20130101; A61M 2205/581 20130101;
A61J 1/2065 20150501; A61M 5/2448 20130101; A61M 5/31553 20130101;
A61J 1/201 20150501; A61M 5/3202 20130101 |
Class at
Publication: |
604/187 |
International
Class: |
A61M 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 25, 1997 |
DK |
0339/97 |
May 5, 1997 |
DK |
0513/98 |
Claims
1. Injection system for preparing a mixture of a solvent and a
medicament and for subsequent dosed injection of the mixture, the
system comprising: a syringe from which set doses are apportioned
from a cylinder ampoule having a first end closed by a pierceable
membrane and a second end closed by a piston which can by a piston
rod, which is successively advanced in a distal direction by the
injection of set doses, be forced into the ampoule to press out a
dose of a medicament stored in the ampoule between the membrane and
the piston through an injection needle piercing the rubber
membrane, wherein the piston rod has coupling means by which it is
coupled to the piston of the ampoule to make this piston follow
movements of the piston rod in both axial directions, and an
ampoule with a piston which is provided with coupling means
designed for co-operation with the coupling means of the piston rod
of the syringe to secure said piston to said piston rod, and a
needle mounted in a needle hub and having an injection part
projecting from a distal side of the hub and a back needle piercing
the membrane of an ampoule when the needle hub is mounted on the
syringe.
2. System according to claim 1, wherein the coupling means of the
piston rod and the piston are mutual engaging threads.
3. Syringe for a system according to claim 1 or 2, wherein means
are provided which even when an ampoule is mounted in the syringe
can be operated to set the piston free to be moved in a proximal
direction.
4. A syringe according to claim 3, wherein the dosing mechanism
comprises a dose setting and injecting member which to set a dose
is rotated from a stop an angle which is proportional with the set
dose and which to inject the set dose is rotated back to the stop,
an inner thread in a tubular housing of the syringe, an outer
thread provided on elements forming a part of a piston rod
assembly, which outer thread is in engagement with the inner thread
of the housing, a unidirectional coupling between the dose setting
and injecting member which only by injecting transmits the rotation
to the piston rod to screw this rod in a distal direction through
the housing, characterised in that the means setting the piston rod
free are means drawing the elements carrying the external thread
out of engagement with the inner thread of the housing.
5. An ampoule for an injection system according to claim 1 or 2,
which ampoule is designed to fit into a syringe for apportioning of
set doses and has a piston provided with coupling means designed
for co-operation with coupling means on the piston rod of said
syringe.
Description
[0001] The invention relates to an injection system for preparing a
mixture of a solvent and a medicament and for subsequent dosed
injection of the mixture, the system comprising:
[0002] a syringe from which set doses are apportioned from a
cylinder ampoule having a first end closed by a pierceable membrane
and a second end closed by a piston which can by a piston rod,
which is successively advanced in a distal direction by the
injection of set doses, be forced into the ampoule to press out a
dose of a medicament stored in the ampoule between the membrane and
the piston through an injection needle piercing the rubber
membrane,
[0003] an ampoule with a solvent fitting into the syringe, and
[0004] a needle mounted in a needle hub and having an injection
part projecting from a distal side of the hub and a back needle
piercing the membrane of an ampoule when the needle hub is mounted
on the syringe.
[0005] Whereas many medicaments are supplied as a solution or a
suspension in pre-filled cylinder ampoules of the kind mentioned
above, some kinds of medicine has a low storability when they are
solved. Therefore these types of medicine are mainly stored in a
vial as a lyophilised powder which is dissolved in a solvent which
is injected in the vial by the user immediately before he is going
to load his syringe with a new ampoule. The solution obtained in
the vial is transmitted to a cylinder ampoule which is then ready
to be mounted in a syringe of the above mentioned kind.
[0006] By the mixing it is important that a precisely measured
amount of solvent is used for dissolving the powder in the vial as
else the concentration of the mixture in the ampoule will be wrong
so that the user loose his control with his medication. A precise
mixing may be obtained by storing the solvent in the cylinder
ampoule which is going to be used for the mixture. From the
manufacturer the ampoule may contain a very precise amount of
solvent which may be injected into the vial through a double ended
needle penetrating the closing membranes of as well the ampoule as
the vial.
[0007] When the powder in the vial is dissolved in the solvent
injected in the vial, the mixture obtained is sucked back into the
ampoule by drawing the piston of this ampoule outward and if the
total amount of solvent was not injected in the vial the exceeding
solvent will be mixed up in the mixture of medicine and solvent
transmitted from the vial back into the ampoule.
[0008] When the piston of the ampoule is drawn outward to suck up
the mixture in the ampoule it is very important that the piston is
not drawn out of the ampoule as it may be difficult to put back
again an as it will inevitably cause spill and contamination of the
medicament.
[0009] From WO 95/12425 is known a device for filling a cylinder
ampoule for use in a syringe of the above mentioned kind. This
apparatus comprises a holder in which an ampoule containing a
measured amount of solvent may be mounted. At its front end the
holder is equipped with a connecting device coupling the outlet end
of the ampoule to a vial into which the solvent shall be injected
to solve a lyophilised medicament. To the rear end of the holder a
support is mounted in which a piston rod may be moved in the axial
direction of the ampoule. The distal end of the piston rod is
screwed into the piston and the proximal end of the piston rod
projects from said support. The solvent in the ampoule may be
pressed through a needle which from the front end of the ampoule
forms a channel to the interior of the vial. The solvent is
transmitted from the ampoule to the vial by pressing the projecting
end of the piston rod which then presses the piston into the
ampoule. The mixture obtained in the vial is thereafter sucked back
into the ampoule by drawing the piston outward. This outward
drawing is made possible by the fact that a rear end of the piston
is provided with a hole with an inner thread which is engaged by an
outer thread at the distal end of the piston rode. The piston rod
support which forms a stop preventing the piston from being drawn
out of the ampoule is fixed to the ampoule holder in such a way
that it cannot be unfixed unless the screw connection between the
piston and the piston rod is brought out of engagement. This way
the risk for inadvertently drawing out the piston is
eliminated.
[0010] However, the described solution implies that different
devices must be carried and used. First the filling device must be
taken apart and the ampoule mounted into said device. Then a
filling procedure must be run through. Thereafter the device must
be taken apart again to remove the filled ampoule, which must then
be installed in the syringe by which a dose may be set and
injected.
[0011] Consequently it is an object of the invention to provide an
injection system which makes a special filling device
superfluous.
[0012] This is obtained by a system of the kind mentioned in the
opening of this application, which system is characterised in that
the piston rod of the syringe and the piston of the ampoule has
co-operating coupling means by which the piston of the ampoule is
secured to the piston rod of the syringe to make said piston follow
movements of the piston rod in both axial directions.
[0013] In such a syringe an ampoule with solvent may be mounted
with the distal end of the piston rod engaging the piston of the
ampoule, and through a needle mounted in the common way on the
syringe the solvent may be injected into a vial by repetitively
setting a dose and injecting this dose through the closing rubber
membrane of the vial until the ampoule is emptied. An adapter may
be mounted between the syringe and the vial to keep these elements
in position during said operation and during the next operation
which is to draw the piston rod in a proximal direction whereby it
due to its engagement with the piston in the ampoule will draw this
piston outward in the ampoule. Thereby the mixture prepared in the
vial by the injection of the solvent will be sucked into the
ampoule from where it may now be apportioned in doses which may be
individually set by the dose setting mechanism.
[0014] The coupling means of the piston rod and the piston may
appropriately be parts of which one carries an outer thread which
can engage an inner thread in the other part. However other kinds
couplings allowing transmission of axial movements in both axial
direction may be used so as snap couplings or bayonet couplings. In
some syringes the piston may be mowed in both axial directions
against the resistance of friction in a piston rod guidance whereas
other syringes are provided with a unidirectional coupling which
allows only a movement of the piston rod and the piston in a distal
direction when an ampoule is mounted in the syringe. When the
ampoule is dismounted the unidirectional coupling is released and
the piston rod may be moved in the proximal direction to a
retracted position which it takes up when a full ampoule is
mounted. In such syringes means may be provided which even when an
ampoule is mounted in the syringe can be operated to set the piston
free to be moved in a proximal direction.
[0015] According to a preferred embodiment of the invention he
dosing mechanism of the syringe comprises a dose setting and
injecting member which to set a dose is rotated from a stop an
angle which is proportional with the set dose and which to inject
the set dose is rotated back to the stop, an inner thread in a
tubular housing of the syringe, an outer thread provided on
elements forming a part of a piston rod assembly, which outer
thread is in engagement with the inner thread of the housing, a
unidirectional coupling between the dose setting and injecting
member which only by injecting transmits the rotation to the piston
rod to screw this rod in a distal direction through the housing,
which syringe may according to the invention be characterised in
that the means setting the piston rod free are means drawing the
elements carrying the external thread out of engagement with the
inner thread of the housing. In such a syringe the means setting
the piston rod free may be means drawing the elements carrying the
external thread of the piston rod out of engagement with the inner
thread of the housing.
[0016] An ampoule according to the invention is an ampoule designed
to fit into a syringe for apportioning of set doses and which
ampoule has a piston provided with coupling means designed for
co-operation with coupling means on the piston rod of said syringe
to secure said piston to said piston rod.
[0017] In the following the invention is described in further
details with reference to the drawing, wherein
[0018] FIG. 1 shows a sectional view of a syringe according to the
invention,
[0019] FIG. 2 shows in an enlarged scale the proximal part of the
syringe shown in FIG. 1,
[0020] FIG. 3 shows a perspective view of a carrier in the syringe
according to FIGS. 1 and 2,
[0021] FIG. 4 shows perspective view of a piston rod assembly for
the syringe shown in FIGS. 1 and 2,
[0022] FIG. 5 shows a perspective view of a piston rod driver for
the syringe shown in FIGS. 1 and 2.
[0023] FIG. 6 shows an expanded view of the piston rod assembly
shown in FIG. 4,
[0024] FIG. 7 shows a sectional view of the piston rod assembly,
and
[0025] FIG. 8 shows the distal end of a syringe coupled to a
vial.
[0026] The syringe in FIG. 1 has a tubular housing 1 with an inner
tubular housing 2. The distal ends of the end of the housings form
a cartridge holder and the proximal ends accommodate mechanisms by
which mixing of a medicament, dose setting and injection are
controlled.
[0027] A piston rod 3 is at its distal end provided with an outer
thread 4 which fits into an inner thread 5 in a piston 6 of an
ampoule 7 which is at its distal end closed by a membrane 8. By
mounting of the ampoule this ampoule is rotated so that the thread
4 of the piston rod 3 engages the thread 5 of the piston in the
ampoule 7. A flange 9 near the distal end of the piston rod 3
defines the distance the piston rod 3 may be screwed into the
piston 6 so that the piston rod 3 is not wedged in the piston 6.
Her the connection between piston and piston rod is shown as a
thread connection but other connections so as bayonet couplings may
be used to secure the piston to the piston rod in such a way that
the piston will follow the piston rod during axial movements
thereof in both directions.
[0028] When the piston 3 of the ampoule 7 is attached to the piston
rod 3 the cartridge holder is closed by an end stopper 10 screwed
on the distal end of the inner housing 2. The membrane 8 of the
ampoule is sealed on this ampoule by a member having a threaded
opening in which a needle hub 11 with a double pointed needle 12
may be received so that one end of the needle 12 penetrates the
rubber membrane 8 of the ampoule 7 whereas the other end of the
needle may be inserted through the skin of a person who shall
receive an injection. When the syringe is not in use the needle
receiving part with the needle may be covered by a cap 13 so that
nobody is hurt by the needle.
[0029] In its withdrawn position as shown in FIG. 1 the piston rod
3 is accommodated in the proximal part of the inner housing where
it is surrounded by a carrier 14 which is shown in FIG. 3 and is a
longitudinal tubular member having three longitudinal slots 15 in
approximately its full length and a flange 16 at its distal end. At
its proximal end the carrier 14 has a part with a not round cross
section and which is snapped into a correspondingly not round
opening in a driver 17 through which rotation is transmitted to the
carrier during injection operation of the syringe as it will be
described below. The carrier 14 may be rotated about its axis but a
ratchet 18 coupled between the carrier 14 and the inner housing 2
has the effect that the carrier is rotatable in only one
direction.
[0030] The proximal part of the housing 1 is surrounded by a cap 19
which may rotate on said proximal part. An edge of the cap 19 is
provided with a dose indicating scale 20 which may by rotation of
the cap be moved relative to an arrow 21 on the housing 1 at the
transition between the proximal and the distal part. A protrusion
22 on outer wall of the housing 1 provides a stop against which a
not shown protrusion in the cap abuts. When the cap is rotated in a
direction away from the stop a circular surface with saw tooth
shaped steps having a steep and an inclined edge provided on the
inner side of the end bottom 23 of the cap 19 slides over a
corresponding surfaced provided on the driver 17. The surfaces are
forced against each other by a spring 24 so that a click is heard
each time the top of the steps on one of the surfaces fall down in
the bottom of the steps on the other surface. When the cap is
rotated back until its protrusion abuts the stop 22 on the outer
wall of the housing 1 the end bottom 23 will transmit the rotation
to the driver 17 as the steep edge of the steps on the circular
surfaces of the end bottom 23 will now abut the steep edges of the
steps on the driver 17. The driver 17 is then rotated and is
rotation is transmitted to the carrier 14 the ratchet 18 being so
oriented that R allows this rotation. FIG. 5 shows a piston rod
driver 25 comprising a disc 26 from the edge of which three
120.degree. displaced flexible arms 27 extend in an axial
direction. At the outer ends of the arms 27 members 28 are provided
each carrying a thread 30 which may engage a matching thread 29 on
the inner side of the proximal part of the inner housing 2 when the
members 28 are supported so that the flexible arms 27 do not bend
away so that the threads 30 and 29 are disengaged.
[0031] The piston rod 3 which at its distal end is provided with
the tread 4 for engagement with a thread in the piston 6 of an
ampoule is a part of a piston rod assembly which is shown in FIG.
4, 5 and 6 in perspective, as an expanded view, and a sectional
view ,respectively. The piston rod 3 is tubular and is at its
proximal end provided with three axial, 120.degree. displaced slots
dividing the end of the piston rod into three tongues 31. At the
bottom end of each of the slots the piston rod is provided with a
protrusion 32 which engages the slots 15 of the carrier 14. The
piston rod driver 25 is mounted with its disc 26 abutting the end
of the tongues 31, its arms 27 engaging the slots between the
tongues 31, and the free ends of its threaded members 28 abutting
the proximal ends of the protrusions 32. The protrusions 32 and the
threaded members 28 of the piston rod driver protrude through the
slots 15 of the carrier and this way rotation of the carrier will
be transmitted to the piston rod 3 and the piston rod driver 25
whereas piston rod 3 and piston rod driver 25 may be axially
displaced relative to the carrier 14. A support member having
protrusions 33 engaging the slots between the tongues 31 of the
piston rod 3 is against the force of a spring 34 axially
displaceable in the piston rod 3 from a position near the distal
end of said slots to a position near the free end of the tongues
31. In the position near the bottom end of the slots the
protrusions 33 will support the members 28 and keep their threads
30 in engagement with the thread 29 of the housing, but when the
protrusion are moved to their position near the end of the tongues
31 the arms 27 of the piston rod driver is supported near the disc
26 and the members 28 may due to the oblique sides of the engaging
threads 29 and 30 be pressed inward toward the axis so that they
may be moved axially with their threads 30 scratching over the
thread 29 in the housing.
[0032] FIG. 6 shows an expanded view of the piston rod assembly. It
is seen that the piston rod assembly is provided by combining a
tubular part forming the actual piston rod 3 and provided with a
thread 4 the active length of which is limited by a flange 9
provided by a ring mounted on the piston rod. The protrusions 32
are provided on a part 35 added to form a part of the piston rod 3.
The same way the slotted part of the piston rod is added as an
individual part. Between the slotted part an the rest of the piston
rod a ring 35 is mounted forming an abutment for the spring 34
which is inserted between said ring and a flange on a tubular
sleeve 36 in which an end of the supporting element is secured. A
spindle 37 extends all the way through the piston rod, the
supporting element and the disc of the piston driver and has at its
distal end a head 39 having a diameter which is larger than the
diameter of the bore in the sleeve 36 so that this head will engage
the flanged end of the sleeve 36 if the spindle is drawn in the
proximal direction and will against the force of the spring 34 move
the supporting element on which the sleeve 36 is secured to a
position wherein its protrusions lies near the free ends of the
tongues 31, The spindle 37 further projects through the driver 17,
the end bottom 23 of the cap 19 and into a button 38. By a thread
39 the spindle is secured to the driver 17 and to the button 39
whereas the diameter of the opening through the end bottom 23 of
the cap 19 is large enough to let the spindle 37 pass freely.
[0033] Due to the ratchet 18 the carrier may only be rotated in a
direction by which the piston driver is rotated relative to the
housing in such a direction that said piston driver is screwed in a
direction towards the distal end of the syringe to press out the
content of an ampoule mounted in the syringe. A dose may therefore
be set by rotating the cap away from the stop 22 in the opposite
direction to make the coupling between the driver 17 and the end
bottom 23 of the cap 19 click over a number of teeth corresponding
to the size of the wanted dose this way giving an audible
indication of the size of the set dose. During the clicking the
button 6 will sink and jump back at each click to give a tactile
indication of the size of the set dose. Thereafter the set dose may
be injected by rotating the cap 19 back to abutment with the stop.
During this rotation the coupling between the end bottom of the cap
and the driver 17 will transmit the rotation to the driver 17 which
will again rotate the carrier 14 which transmits the rotation to
the piston driver to screw it along the housing 2 a distance
proportional with the angle of rotation.
[0034] When the syringe is going to be used for injection of a
medicament which has to be mixed from two or more components
immediately before the use, an ampoule with a solvent component is
mounted in the syringe, a needle is mounted and the free end of
this needle is inserted in a vial containing another possibly solid
component of the medicament. In FIG. 8 this insertion is
illustrated by a vial 40 which is closed by a stopper 41 through
which the needle 12 is inserted. It is further illustrated how an
adapter 42 may be placed on the vial 40 which adapter has a socket
to which the distal end of the syringe may be mounted using the
coupling which normally is used for fixing the needle protection
cap 13. With the needle inserted in the vial repetitive dose
setting and injection rotations of the cap is performed whereby the
piston is successively moved into the ampoule until the full
content thereof is injected into the vial 40.
[0035] Hereafter the vial may be turned upside down still with the
needle inserted through the stopper of the vial. Now the piston in
the ampoule may be drawn back to its position corresponding to a
full ampoule whereby the mixture provided in the vial may be sucked
back into the ampoule. This is obtained by drawing the cap in a
proximal direction which means that the spindle 37 is pulled in
this direction. Hereby the driver which is secured to the spindle
and snap locked onto the carrier 14 will first be lifted off said
carrier where after the spindle may be moved freely until its head
39 abuts the sleeve 36. Further movement of the spindle 37 will
cause a compression of the spring 34 and the protrusions of the
support member will be moved to their position near the free end of
the tongues 31 where the piston threaded members 28 of the piston
driver 25 is no longer supported. The axial pull of the spindle is
now transmitted to the piston rod which is restrained in moving due
to the engagement between the inner thread in the housing and the
threaded members 28 of the piston drive. However, due to the
lacking support of the members 28 these may be bend inward towards
the axis and the engagement between the threads 29 and 30 may be
released so that the piston rod 3 may be drawn backward with the
piston drive members scratching over the thread 29 in the housing.
Due to the engagement between the thread 4 at the distal end of the
piston rod 3 and the thread in the piston 6 of the ampoule 7 said
piston is drawn outwards in the ampoule and the content from the
vial 40 is sucked over into the ampoule 7. When the spindle 37
thereafter is moved back to its original position the spring 34 is
released and the support member is moved back so that its
protrusions 33 support the threaded members of the piston rod
driver 25 to keep the tread of these members in engagement with the
inner thread 29 of the housing. Finally the driver 17 is snapped
onto the carrier 14 again and the syringe is ready for use as a
syringe by which a dose may be set and injected.
[0036] In the syringe described the piston rod is bound to be moved
in the distal direction by the dosing mechanism due to the ratchet
18 which provides a one way coupling which ensures that the piston
rod is only movable in said distal direction as long as it is
coupled to the dosing mechanism. In other types of syringes the
piston rod is prevented from being moved in a proximal direction by
detent mechanisms comprising a pawl which secured to the housing
engages a toothing along the piston rod or comprising a leaf spring
which secured to the housing cuts into the piston rod. To realise
the invention such a pawl engagement or cutting engagement may by
appropriate members be operated to be disengaged to set the piston
free to be moved in a proximal direction.
[0037] In the above description the mutual engaging threads of the
piston rod and the piston are provided as an outer thread at the
end of the piston rod which engage an inner thread in a bore in the
piston. Alternatively the piston can be provided with a threaded
stud engaging an inner thread in a bore in the end of the piston
rod.
* * * * *