Gasket for bypass type prefilled syringe

Details Gasket for bypass type prefilled syringe Gasket for bypass type prefilled syringe

2002-03-08

2004-05-25

Casler, Brian L. (Department: 3763)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

C604S089000, C604S218000, C604S236000

Reexamination Certificate

active

06740060

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a bypass type prefilled syringe in which a bypass for establishing communication between front and rear compartments for preliminarily storing two components, for example, powdery medicament and pharmaceutical liquid, respectively is formed on a tubular body, and more particularly to a gasket for dividing interior space of the tubular body of the bypass type prefilled syringe into the front and rear compartments.
2. Description of the Prior Art
FIGS. 6 and 7
show a sealing state and a communication state between a front compartment
6
and a rear compartment
7
of an elongated hollow tubular body
1
of a conventional bypass type prefilled syringe, respectively. A front assembly
15
includes an injection needle
10
and a cap
11
for covering the injection needle
10
so as to protect the injection needle
10
and is mounted on an outer periphery of a front end portion of the tubular body
1
. In
FIG. 6
, the conventional bypass type prefilled syringe includes a first sealing member
3
which is mounted in the front end portion of the tubular body
1
, a second sealing member
4
which is attached to a front end of a plunger rod
2
and is disposed at a rear end portion of the tubular body
1
and a gasket
5
which is slidably inserted between the first and second sealing members
3
and
4
in the tubular body
1
and divides interior space of the tubular body
1
into the front and rear compartments
6
and
7
. Powdery medicament P and pharmaceutical liquid L are preliminarily, respectively, stored in the front and rear compartments
6
and
7
so as to interpose the gasket
5
therebetween.
A bypass
1
a
is formed by bulging a peripheral wall of the front compartment
6
of the tubular body
1
radially outwardly. On the other hand, a finger grip
12
is mounted on an outer periphery of the rear end portion of the tubular body
1
. By forwardly depressing the plunger rod
2
in the direction of the arrow a in
FIG. 7
from the state of
FIG. 6
to the state of
FIG. 7
, the gasket
5
is advanced by the second sealing member
4
by way of the pharmaceutical liquid L so as to be disposed between a front end portion and a rear end portion of the bypass
1
a
. At this time, a gap for directly linking the front and rear compartments
6
and
7
is defined between the gasket
5
and the bypass
1
a
, so that the front and rear compartments
6
and
7
are communicated with each other by the bypass
1
a
and thus, the pharmaceutical liquid L is introduced from the rear compartment
7
into the powdery medicament P in the front compartment
6
along a flow path indicated by the arrow b in FIG.
7
. Then, when the powdery medicament P is sufficiently dissolved or dispersed in the pharmaceutical liquid L by shaking the tubular body
1
, injection liquid is formed.
At the time of communication between the front and rear compartments
6
and
7
through the bypass
1
a
in this conventional bypass type prefilled syringe, the pharmaceutical liquid L is fed under pressure into the front compartment
6
in a state where the injection needle
10
is mounted on the tubular body
1
. At this time, the gasket
5
is disposed between the front end portion and the rear end portion of the bypass
1
a
and the gap for directly linking the front and rear compartments
6
and
7
is defined between the gasket
5
and the bypass
1
a
as described above. Thus, in case a user forcibly depresses the plunger rod
2
from the state of
FIG. 6
to the state of
FIG. 7
, a so-called squirt phenomenon in which the pharmaceutical liquid L spouts from the bypass
1
a
vigorously may happen, thereby resulting in such an inconvenience that the pharmaceutical liquid L impinges on the first sealing member
3
and then, leaks out of the injection needle
10
.
Meanwhile,
FIG. 8
shows a sealing state between the front and rear compartments
6
and
7
of the tubular body
1
of a known bypass type prefilled syringe disclosed in U.S. Pat. No. 4,599,082. In this known bypass type prefilled syringe, a gasket
20
is employed. As shown in
FIG. 9
, the gasket
20
has a front end face
20
a
and a rear end face
20
b
and includes ribs
24
,
26
and
27
. Meanwhile, an annular recess
25
is provided between the ribs
24
and
26
and a plurality of grooves
28
extending obliquely relative to an axis of the gasket
20
are formed on the rib
24
so as to open to the front end face
20
a
. In order to improve agitation and mixing of the pharmaceutical liquid L and the powdery medicament P at the time of communication between the front and rear compartments
6
and
7
via the bypass
1
a
, the pharmaceutical liquid L is introduced from the grooves
28
into the powdery medicament P obliquely relative to the axis of the gasket
20
.
However, in contrast with the conventional construction shown in
FIGS. 6 and 7
in which the injection needle
10
is mounted on the front end portion of the tubular body
1
, this known bypass type prefilled syringe has a construction in which a distal end cap
35
is mounted on a distal end
34
of the tubular body
1
. Thus, as described at column 8, lines 3 to 9 of the above mentioned U.S. Patent, mixing operation of the pharmaceutical liquid L and the powdery medicament P is performed by depressing a plunger rod in a state where the distal end
34
of the tubular body
1
is directed upwardly after the distal end cap
35
has been removed from the distal end
34
of the tubular body
1
. Therefore, the gasket
20
merely serves to improve agitation and mixing of the pharmaceutical liquid L and the powdery medicament P and thus does not serve to prevent leakage of the pharmaceutical liquid L from an injection needle due to the squirt phenomenon.
SUMMARY OF THE INVENTION
Accordingly, an essential object of the present invention is to provide, with a view to eliminating the above mentioned drawbacks of prior art, a gasket for a bypass type prefilled syringe which prevents a squirt phenomenon of pharmaceutical liquid at the time of communication between front and rear compartments of a tubular body by way of a bypass such that powdery medicament can be sufficiently dissolved or dispersed in the pharmaceutical liquid.
In order to accomplish this object of the present invention, a gasket for a bypass type prefilled syringe having a tubular body formed with a bypass for establishing communication between front and rear compartments for preliminarily storing medicament and pharmaceutical liquid, respectively, according to the present invention divides interior space of the tubular body into the front and rear compartments and includes a plurality of circumferential ribs which include at least first, second and third circumferential ribs disposed sequentially further away from the front compartment. A plurality of annular recesses are each formed between neighboring ones of the circumferential ribs and include at least a first annular recess formed between the first and second circumferential ribs and a second annular recess formed between the second and third circumferential ribs. A first axial slot extends through the first circumferential rib and the first annular recess, while a second axial slot is formed at a circumferential position of the second circumferential rib deviating from the first axial slot so as to bring the first and second annular recesses into communication with each other. At the time of communication between the front and rear compartments via the bypass, a bent outflow path for delivering the pharmaceutical liquid into the front compartment in a state where the tubular body at a front end side of the bypass is closed by a front end portion of the gasket is sequentially formed by the second annular recess, the second axial slot, the first annular recess and the first axial slot.


REFERENCES:
patent: 4599082 (1986-07-01), Grimard
patent: 4613326 (1986-09-01), Szwarc
patent: 5489266 (1996-02-01), Grimard
patent: 5685846 (1997-11-01), Michaels, Jr.
patent: 5743890

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