U.S. patent application number 11/833471 was filed with the patent office on 2008-01-24 for plunger linkage and seal for ophthalmic medical device.
Invention is credited to Cesario Dos Santos, James J. Foster, Dyson W. Hickingbotham, Raffi Pinedjian, Robert J. Sanchez.
Application Number | 20080021412 11/833471 |
Document ID | / |
Family ID | 38420664 |
Filed Date | 2008-01-24 |
United States Patent
Application |
20080021412 |
Kind Code |
A1 |
Dos Santos; Cesario ; et
al. |
January 24, 2008 |
Plunger Linkage and Seal For Ophthalmic Medical Device
Abstract
A disposable injection device has a dispensing chamber housing
and a plunger. The dispensing chamber housing has an inner surface
and an outer surface. The inner surface partially defines a
dispensing chamber for receiving a quantity of a substance. The
plunger is engaged with the inner surface of the dispensing chamber
housing, is capable of sliding in the dispensing chamber housing,
and is fluidly sealed to the inner surface of the dispensing
chamber housing. The plunger has a plunger interface. The plunger
interface mates with a mating surface on a mechanical linkage
interface such that force is transferred from the mechanical
linkage interface to the plunger along a first direction towards
the plunger when the plunger interface is in contact with the
mating surface of the mechanical linkage interface, and force is
not substantially transferred from the mechanical linkage interface
to the plunger along a second direction away from the plunger.
Inventors: |
Dos Santos; Cesario; (Aliso
Viejo, CA) ; Foster; James J.; (Santa Ana, CA)
; Pinedjian; Raffi; (Fountain Valley, CA) ;
Hickingbotham; Dyson W.; (Stouchsberg, PA) ; Sanchez;
Robert J.; (Oceanside, CA) |
Correspondence
Address: |
ALCON
IP LEGAL, TB4-8
6201 SOUTH FREEWAY
FORT WORTH
TX
76134
US
|
Family ID: |
38420664 |
Appl. No.: |
11/833471 |
Filed: |
August 3, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11435906 |
May 17, 2006 |
|
|
|
11833471 |
Aug 3, 2007 |
|
|
|
Current U.S.
Class: |
604/218 |
Current CPC
Class: |
A61M 60/40 20210101;
A61M 2205/8206 20130101; A61F 9/0017 20130101; A61M 5/31511
20130101; A61M 2205/0266 20130101; A61M 2205/3331 20130101; A61M
5/1452 20130101; A61M 2205/8262 20130101; A61M 5/14546 20130101;
A61M 2210/0612 20130101; A61M 5/484 20130101 |
Class at
Publication: |
604/218 |
International
Class: |
A61M 5/315 20060101
A61M005/315 |
Claims
1. A disposable injection device comprising: a dispensing chamber
housing having an inner surface and an outer surface, the inner
surface partially defining a dispensing chamber for receiving a
quantity of a substance; and a plunger engaged with the inner
surface of the dispensing chamber housing, the plunger capable of
sliding in the dispensing chamber housing, the plunger fluidly
sealed to the inner surface of the dispensing chamber housing, the
plunger having a plunger interface; wherein the plunger interface
mates with a mating surface on a mechanical linkage interface such
that force is transferred from the mechanical linkage interface to
the plunger along a first direction towards the plunger when the
plunger interface is in contact with the mating surface of the
mechanical linkage interface, and force is not substantially
transferred from the mechanical linkage interface to the plunger
along a second direction away from the plunger.
2. The device of claim 1 further comprising: a housing at least
partially enclosing the dispensing chamber housing and the
plunger.
3. The device of claim 1 further comprising: a needle fluidly
coupled to the dispensing chamber.
4. The device of claim 1 further comprising: a temperature control
device in thermal contact with the dispensing chamber, the
temperature control device for altering the temperature of the
substance.
5. The device of claim 4 further comprising: a thermal sensor in
thermal contact with the dispensing chamber.
6. The device of claim 1 wherein the substance is a drug for
treating a condition of the eye.
7. The device of claim 1 wherein the plunger further comprises: an
o-ring located around the plunger, the o-ring for fluidly sealing
the plunger to the inner surface of the dispensing chamber
housing.
8. The device of claim 7 wherein the plunger is made of a material
selected from the group consisting of stainless steel, elastomer,
and polymer.
9. The device of claim 1 wherein the plunger further comprises: an
annular ring located around the plunger, the annular ring for
fluidly sealing the plunger to the inner surface of the dispensing
chamber housing.
10. The device of claim 1 wherein the plunger is over molded onto a
rigid shaft, and the plunger interface is located on a proximal end
of the shaft.
11. The device of claim 1 wherein the plunger is press-fitted onto
a rigid shaft, and the plunger interface is located on a proximal
end of the shaft.
12. The device of claim 1 wherein the plunger interface is
substantially concave and the mating surface is substantially
convex.
13. The device of claim 1 wherein the plunger interface is
substantially convex and the mating surface is substantially
concave.
14. The device of claim 1 wherein the plunger interface and the
mating surface are both substantially flat.
15. The device of claim 1 further comprising: the mechanical
linkage interface and an actuator for driving the mechanical
linkage interface.
16. An ophthalmic injection system comprising: a tip segment and a
limited reuse assembly; the tip segment comprising: a dispensing
chamber housing having an inner surface and an outer surface, the
inner surface partially defining a dispensing chamber for receiving
a quantity of a substance; and a plunger engaged with the inner
surface of the dispensing chamber housing, the plunger capable of
sliding in the dispensing chamber housing, the plunger fluidly
sealed to the inner surface of the dispensing chamber housing, the
plunger having a plunger interface; the limited reuse assembly
comprising: a power source; an actuator having a shaft; a
controller for controlling the actuator; and a mechanical linkage
interface coupled to the shaft, the mechanical linkage interface
having a mating surface on an end; wherein the plunger interface
mates with the mating surface on the mechanical linkage interface
such that force is transferred from the mechanical linkage
interface to the plunger along a first direction towards the
plunger when the plunger interface is in contact with the mating
surface of the mechanical linkage interface, and force is not
substantially transferred from the mechanical linkage interface to
the plunger along a second direction away from the plunger.
17. The ophthalmic injection system of claim 16 wherein the tip
segment further comprises: a needle fluidly coupled to the
dispensing chamber.
18. The ophthalmic injection system of claim 16 wherein the tip
segment further comprises: a temperature control device in thermal
contact with the dispensing chamber, the temperature control device
for altering the temperature of the substance.
19. The ophthalmic injection system of claim 18 wherein the tip
segment further comprises: a thermal sensor in thermal contact with
the dispensing chamber.
20. The ophthalmic injection system of claim 16 wherein the
substance is a drug for treating a condition of the eye.
21. The ophthalmic injection system of claim 16 wherein the tip
segment further comprises: an o-ring located around the plunger,
the o-ring for fluidly sealing the plunger to the inner surface of
the dispensing chamber housing.
22. The ophthalmic injection system of claim 21 wherein the plunger
is made of a material selected from the group consisting of
stainless steel, elastomer, and polymer.
23. The ophthalmic injection system of claim 16 wherein the tip
segment further comprises: an annular ring located around the
plunger, the annular ring for fluidly sealing the plunger to the
inner surface of the dispensing chamber housing.
24. The ophthalmic injection system of claim 16 wherein the plunger
is over molded onto a rigid shaft, and the plunger interface is
located on a proximal end of the shaft.
25. The ophthalmic injection system of claim 16 wherein the plunger
is press-fitted onto a rigid shaft, and the plunger interface is
located on a proximal end of the shaft.
26. The ophthalmic injection system of claim 16 wherein the plunger
interface is substantially concave and the mating surface is
substantially convex.
27. The ophthalmic injection system of claim 16 wherein the plunger
interface is substantially convex and the mating surface is
substantially concave.
28. The ophthalmic injection system of claim 16 wherein the plunger
interface and the mating surface are both substantially flat.
29. The ophthalmic injection system of claim 19 further comprising:
an electrical interface for coupling the temperature control device
to the limited reuse assembly.
30. The ophthalmic injection system of claim 16 wherein the
controller operates the actuator such that the shaft is moved a
calculated distance thereby displacing the plunger and causing a
fixed amount of the substance to exit the dispensing chamber.
31. The ophthalmic injection system of claim 16 wherein the power
source is a battery.
32. The ophthalmic injection system of claim 16 wherein the
mechanical linkage interface is rigidly coupled to the shaft.
33. The ophthalmic injection system of claim 16 wherein the
mechanical linkage interface is coupled to the shaft with a ball
joint.
34. The ophthalmic injection system of claim 16 wherein the
mechanical linkage interface is tapered near the end on which the
mating surface is located.
35. A dispensing mechanism for use in an ophthalmic drug delivery
device comprising: a dispensing chamber housing having an inner
surface and an outer surface, the inner surface partially defining
a dispensing chamber for receiving a quantity of a substance; a
plunger engaged with the inner surface of the dispensing chamber
housing, the plunger capable of sliding in the dispensing chamber
housing, the plunger fluidly sealed to the inner surface of the
dispensing chamber housing, the plunger having a plunger interface;
and a mechanical linkage interface having a mating surface on one
end; wherein the plunger interface mates with the mating surface on
the mechanical linkage interface such that force is transferred
from the mechanical linkage interface to the plunger along a first
direction towards the plunger when the plunger interface is in
contact with the mating surface of the mechanical linkage
interface, and force is not substantially transferred from the
mechanical linkage interface to the plunger along a second
direction away from the plunger.
36. The dispensing mechanism of claim 35 further comprising: a
temperature control device in thermal contact with the dispensing
chamber, the temperature control device for altering the
temperature of the substance.
37. The dispensing mechanism of claim 35 further comprising: an
o-ring located around the plunger, the o-ring for fluidly sealing
the plunger to the inner surface of the dispensing chamber
housing.
38. The dispensing mechanism of claim 35 further comprising: an
annular ring located around the plunger, the annular ring for
fluidly sealing the plunger to the inner surface of the dispensing
chamber housing.
39. The dispensing mechanism of claim 35 wherein the plunger is
over molded onto a rigid shaft, and the plunger interface is
located on a proximal end of the shaft.
40. The dispensing mechanism of claim 35 wherein the plunger is
press-fitted onto a rigid shaft, and the plunger interface is
located on a proximal end of the shaft.
41. The dispensing mechanism of claim 35 wherein the plunger
interface is substantially concave and the mating surface is
substantially convex.
42. The dispensing mechanism of claim 35 wherein the plunger
interface is substantially convex and the mating surface is
substantially concave.
43. The dispensing mechanism of claim 35 wherein the plunger
interface and the mating surface are both substantially flat.
44. The dispensing mechanism of claim 35 further comprising: an
actuator with a shaft, the shaft connected to the mechanical
linkage interface.
45. The dispensing mechanism of claim 44 wherein the mechanical
linkage interface is rigidly coupled to the shaft.
46. The dispensing mechanism of claim 44 wherein the mechanical
linkage interface is coupled to the shaft with a ball joint.
47. The dispensing mechanism of claim 35 wherein the mechanical
linkage interface is tapered near the end on which the mating
surface is located.
48. The dispensing mechanism of claim 35 wherein the plunger
interface and the mating surface permit transfer of motion only in
a single direction.
49. The dispensing mechanism of claim 35 wherein when the
mechanical linkage interface is retracted, the plunger remains in
substantially the same position.
Description
RELATED APPLICATIONS
[0001] This Application is a continuation-in-part of U.S. patent
application Ser. No. 11/581,629 filed Oct. 16, 2006, U.S. patent
application Ser. No. 11/581,630 filed Oct. 16, 2006, U.S. patent
application Ser. No. 11/581,591 filed Oct. 16, 2006, and U.S.
patent application Ser. No. 11/435,906 filed May 17, 2006.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a single-use medical device
and more particularly to a two-piece ophthalmic drug delivery
device with a disposable tip end containing an improved plunger
linkage and seal.
[0003] Several diseases and conditions of the posterior segment of
the eye threaten vision. Age related macular degeneration (ARMD),
choroidal neovascularization (CNV), retinopathies (e.g., diabetic
retinopathy, vitreoretinopathy), retinitis (e.g., cytomegalovirus
(CMV) retinitis), uveitis, macular edema, glaucoma, and
neuropathies are several examples.
[0004] These, and other diseases, can be treated by injecting a
drug into the eye. Such injections are typically manually performed
using a conventional syringe and needle. FIG. 1 is a perspective
view of a prior art syringe used to inject drugs into the eye. In
FIG. 1, the syringe includes a needle 105, a luer hub 110, a
chamber 115, a plunger 120, a plunger shaft 125, and a thumb rest
130. As is commonly known, the drug to be injected is located in
chamber 115. Pushing on the thumb rest 130 causes the plunger 120
to expel the drug through needle 105.
[0005] In using such a syringe, the surgeon is required to pierce
the eye tissue with the needle, hold the syringe steady, and
actuate the syringe plunger (with or without the help of a nurse)
to inject the fluid into the eye. Fluid flow rates are
uncontrolled. Reading the vernier is subject to parallax error
which affects the precision and accuracy of the injected volume.
Tissue damage may occur due to an "unsteady" injection. Reflux of
the drug may also occur when the needle is removed from the
eye.
[0006] An effort has been made to control the delivery of small
amounts of liquids. A commercially available fluid dispenser is the
ULTRA.TM. positive displacement dispenser available from EFD Inc.
of Providence, R.I. The ULTRA dispenser is typically used in the
dispensing of small volumes of industrial adhesives. It utilizes a
conventional syringe and a custom dispensing tip. The syringe
plunger is actuated using an electrical stepper motor and an
actuating fluid. With this type of dispenser, the volumes delivered
are highly dependent on fluid viscosity, surface tension, and the
specific dispensing tip. Parker Hannifin Corporation of Cleveland,
Ohio distributes a small volume liquid dispenser for drug discovery
applications made by Aurora Instruments LLC of San Diego, Calif.
The Parker/Aurora dispenser utilizes a piezo-electric dispensing
mechanism. While precise, this dispenser is expensive and requires
an electrical signal to be delivered to the dispensing
mechanism.
[0007] U.S. Pat. No. 6,290,690 discloses an ophthalmic system for
injecting a viscous fluid (e.g. silicone oil) into the eye while
simultaneously aspirating a second viscous fluid (e.g.
perflourocarbon liquid) from the eye in a fluid/fluid exchange
during surgery to repair a retinal detachment or tear. The system
includes a conventional syringe with a plunger. One end of the
syringe is fluidly coupled to a source of pneumatic pressure that
provides a constant pneumatic pressure to actuate the plunger. The
other end of the syringe is fluidly coupled to an infusion cannula
via tubing to deliver the viscous fluid to be injected.
[0008] It would be desirable to have a portable hand piece for
injecting a drug into the eye. Such a hand piece includes a limited
reuse assembly attachable to and removable from a disposable tip
segment. The disposable tip segment contains the drug, a needle for
administering the drug, a plunger, and various other components.
The limited reuse assembly includes a mechanism for driving the
plunger to expel the drug from the disposable tip segment. The
actuation of the plunger in the disposable tip segment is
controlled by the limited reuse assembly. It would be desirable to
have a plunger linkage and seal that maintains the sterility of the
disposable tip segment and prevents reflux when the needle is
removed from the eye after an injection.
SUMMARY OF THE INVENTION
[0009] In one embodiment consistent with the principles of the
present invention, the present invention is a disposable injection
device having a dispensing chamber housing and a plunger. The
dispensing chamber housing has an inner surface and an outer
surface. The inner surface partially defines a dispensing chamber
for receiving a quantity of a substance. The plunger is engaged
with the inner surface of the dispensing chamber housing, is
capable of sliding in the dispensing chamber housing, and is
fluidly sealed to the inner surface of the dispensing chamber
housing. The plunger has a plunger interface. The plunger interface
mates with a mating surface on a mechanical linkage interface such
that force is transferred from the mechanical linkage interface to
the plunger along a first direction towards the plunger when the
plunger interface is in contact with the mating surface of the
mechanical linkage interface, and force is not substantially
transferred from the mechanical linkage interface to the plunger
along a second direction away from the plunger.
[0010] In another embodiment consistent with the principles of the
present invention, the present invention is an ophthalmic injection
system having a tip segment and a limited reuse assembly. The tip
segment has a dispensing chamber housing and a plunger. The
dispensing chamber housing has an inner surface and an outer
surface. The inner surface partially defines a dispensing chamber
for receiving a quantity of a substance. The plunger is engaged
with the inner surface of the dispensing chamber housing, is
capable of sliding in the dispensing chamber housing, and is
fluidly sealed to the inner surface of the dispensing chamber
housing. The plunger has a plunger interface. The limited reuse
assembly has a power source, an actuator with a shaft, a controller
for controlling the actuator, and a mechanical linkage interface.
The mechanical linkage interface is coupled to the shaft and has a
mating surface on an end. The plunger interface mates with the
mating surface on the mechanical linkage interface such that force
is transferred from the mechanical linkage interface to the plunger
along a first direction towards the plunger when the plunger
interface is in contact with the mating surface of the mechanical
linkage interface, and force is not substantially transferred from
the mechanical linkage interface to the plunger along a second
direction away from the plunger.
[0011] In another embodiment consistent with the principles of the
present invention, the present invention is a dispensing mechanism
for use in an ophthalmic drug delivery device. The dispensing
mechanism has a dispensing chamber, a plunger, and a mechanical
linkage interface. The dispensing chamber housing has an inner
surface and an outer surface. The inner surface partially defines a
dispensing chamber for receiving a quantity of a substance. The
plunger is engaged with the inner surface of the dispensing chamber
housing, is capable of sliding in the dispensing chamber housing,
and is fluidly sealed to the inner surface of the dispensing
chamber housing. The plunger has a plunger interface. The
mechanical linkage interface has a mating surface on one end. The
plunger interface mates with the mating surface on the mechanical
linkage interface such that force is transferred from the
mechanical linkage interface to the plunger along a first direction
towards the plunger when the plunger interface is in contact with
the mating surface of the mechanical linkage interface, and force
is not substantially transferred from the mechanical linkage
interface to the plunger along a second direction away from the
plunger
[0012] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are intended to provide further
explanation of the invention as claimed. The following description,
as well as the practice of the invention, set forth and suggest
additional advantages and purposes of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The accompanying figures, which are incorporated in and
constitute a part of this specification, illustrate several
embodiments of the invention and together with the description,
serve to explain the principles of the invention.
[0014] FIG. 1 is a perspective view of a prior art syringe.
[0015] FIG. 2 is a view of an ophthalmic medical device including a
disposable tip segment and a limited reuse assembly according to an
embodiment of the present invention.
[0016] FIG. 3 is an embodiment of a limited reuse assembly
according to the principles of the present invention.
[0017] FIG. 4 is an exploded cross section view of a disposable tip
segment for an ophthalmic hand piece according to an embodiment of
the present invention.
[0018] FIG. 5 is cross section view of a disposable tip segment and
a limited reuse assembly according to an embodiment of the present
invention.
[0019] FIGS. 6-16 are cross section views of various plunger and
mechanical linkage interface designs according to the principles of
the present invention.
[0020] FIGS. 17-18 are cross section views of two subassemblies
according to the principles of the present invention.
[0021] FIGS. 19-20 are methods of operating an ophthalmic medical
device according to the principles of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Reference is now made in detail to the exemplary embodiments
of the invention, examples of which are illustrated in the
accompanying figures. Wherever possible, the same reference numbers
are used throughout the figures to refer to the same or like
parts.
[0023] FIG. 2 depicts one view of an ophthalmic medical device
including a disposable tip segment and a limited reuse assembly
according to an embodiment of the present invention. In FIG. 2, the
medical device includes a tip segment 205 and a limited reuse
assembly 250. The tip segment 205 includes a needle 210, a housing
215, and an optional light 275. The limited reuse assembly 250
includes a housing 255, a switch 270, a lock mechanism 265, and a
threaded portion 260.
[0024] Tip segment 205 is capable of being connected to and removed
from limited reuse assembly 250. In this embodiment, tip segment
205 has a threaded portion on an interior surface of housing 215
that screws onto the threaded portion 260 of limited reuse assembly
250. In addition, lock mechanism 265 secures tip segment 215 to
limited reuse assembly 250. Lock mechanism 265 may be in the form
of a button, a sliding switch, or a cantilevered mechanism. Other
mechanisms for connecting tip segment 205 to limited reuse assembly
250, such as those involving structural features that mate with
each other, are commonly known in the art and are within the scope
of the present invention.
[0025] Needle 210 is adapted to deliver a substance, such as a
drug, into an eye. Needle 210 may be of any commonly known
configuration. Preferably, needle 210 is designed such that its
thermal characteristics are conducive to the particular drug
delivery application. For example, when a heated drug is to be
delivered, needle 210 may be relatively short (several millimeters)
in length to facilitate proper delivery of the drug based on
thermal characteristics.
[0026] Switch 270 is adapted to provide an input to the system. For
example, switch 270 may be used to activate the system or to turn
on a heater. Other switches, buttons, or user-directed control
inputs are commonly known and may be employed with limited reuse
assembly 250 and/or tip segment 205.
[0027] Optional light 275 is illuminated when tip segment 205 is
ready to be used. Optional light 275 may protrude from housing 215,
or it may be contained within housing 215, in which case, optional
light 275 may be seen through a clear portion of housing 215. In
other embodiments, optional light 275 may be replaced by an
indicator, such as a liquid crystal display, segmented display, or
other device that indicates a status or condition of disposable tip
segment 205. For example, optional light 275 may also pulse on and
off to indicate other states, such as, but not limited to a system
error, fully charged battery, insufficiently charged battery or
faulty connection between the tip segment 205 and limited use
assembly 250. While shown on tip segment 205, optional light 275 or
other indicator may be located on limited reuse assembly 250.
[0028] FIG. 3 is another embodiment of a limited reuse assembly
according to the principles of the present invention. Limited reuse
assembly 250 includes a button 310, a display 320, and a housing
330. Disposable tip segment 205 attaches to end 340 of limited
reuse assembly 250. Button 310 is actuated to provide an input to
the system. As with switch 270, button 310 may activate a heater or
other temperature control device or initiate actuation of a
plunger. Display 320 is a liquid crystal display, segmented
display, or other device that indicates a status or condition of
disposable tip segment 205 or limited reuse assembly 250.
[0029] FIG. 4 is a cross section view of a disposable tip segment
for an ophthalmic medical device according to an embodiment of the
present invention. In FIG. 4, disposable tip segment 205 includes
housing 215, needle 210, plunger 415, dispensing chamber 405,
dispensing chamber housing 425, assembly 555, temperature control
device 450, thermal sensor 460, and optional luer 430. Disposable
tip segment 205 operates as a disposable injection device.
[0030] In the embodiment of FIG. 4, plunger 415 is located in
dispensing chamber housing 425. Dispensing chamber 405 is enclosed
by dispensing chamber housing 425 and plunger 415. Plunger 415
forms a fluid seal with the interior surface of dispensing chamber
housing 425. Needle 210 is fluidly coupled to dispensing chamber
405. In this manner, a substance located in dispensing chamber 405
can be contacted by plunger 415 and pushed out of needle 210.
Needle 210 may be secured to disposable tip segment 205 by an
optional luer 430 or may be permanently attached. Temperature
control device 450 is located on dispensing chamber housing 425 and
at least partially surrounds dispensing chamber 405. Housing 215
forms an outer skin on disposable tip segment 205.
[0031] In various embodiments of the present invention, temperature
control device 450 is a heating and/or a cooling device.
Temperature control device 450 is in thermal contact with
dispensing chamber housing 425. As such, temperature control device
450 is capable of changing the temperature of the substance in
dispensing chamber 405.
[0032] Assembly 555 can include any of a number of different
components. In one embodiment, assembly 555 contains a fuse that is
blown when the heat button is activated or after disposable tip
segment 205 is used. In this manner, the fuse prevents reuse of
disposable tip segment 205. In another embodiment, assembly 555
includes a memory device that stores information about the type of
disposable tip segment 205, dosage information, temperature
information, plunger movement information, or any other type of
information that identifies a characteristic of disposable tip
segment 205 or a manner in which disposable tip segment 205 is
operated. In other embodiments, assembly 205 includes a hard-wired
memory device, like a NAND flash IC, an RFID tag, a hard-wired
wired circuit that can store a representation of data, like a
series of fuses and resistors connected in parallel or other type
of device.
[0033] A substance to be delivered into an eye, typically a drug,
is located in dispensing chamber 405. In this manner, the substance
is contacted by the inner surface of dispensing chamber housing 425
and one face of plunger 415. Typically, dispensing chamber 405 is
cylindrical in shape. Temperature control device 450 is in thermal
contact with dispensing chamber housing 425. In this manner,
temperature control device 450 is adapted to control the
temperature of the contents of dispensing chamber 425. Thermal
sensor 460 provides temperature information to assist in
controlling the operation of temperature control device 450.
[0034] In one embodiment of the present invention, the substance
located in dispensing chamber 405 is a drug that is preloaded into
the dispensing chamber. In such a case, disposable tip segment 205
is appropriate as a single use consumable product. Such a
disposable product can be assembled at a factory with a dosage of a
drug installed.
[0035] When a drug is preloaded into dispensing chamber 405, a set
quantity of the drug can be preloaded. For example, 100 microliters
of a drug can be loaded into dispensing chamber 405, and any
quantity up to 100 microliters can be dispensed. Information about
the amount of drug in dispensing chamber 205 and other dosage
information can be stored in assembly 555. In such a case, the
plunger 415 can be moved a precise distance to deliver a precise
dosage of drug from the dispensing chamber 405, through the needle
210, and into an eye. This provides for flexibility of dosing and
for ease of assembly.
[0036] FIG. 5 is a cross section view of a disposable tip segment
and a limited reuse assembly according to an embodiment of the
present invention. FIG. 5 shows how tip segment 205 interfaces with
limited reuse assembly 250. In the embodiment of FIG. 5, tip
segment 205 includes assembly 555, plunger interface 420, plunger
415, dispensing chamber housing 425, tip segment housing 215,
temperature control device 450, thermal sensor 460, needle 210,
dispensing chamber 405, interface 530, and tip interface connector
520. Limited reuse assembly 250 includes mechanical linkage 545,
actuator shaft 510, actuator 515, power source 310, controller 305,
limited reuse assembly housing 255, interface 535, and limited
reuse assembly interface connector 525.
[0037] In tip segment 205, plunger interface 420 is located on one
end of plunger 415. The other end of plunger 415 forms one end of
dispensing chamber 405. Plunger 415 is adapted to slide within
dispensing chamber 405. An outer surface of plunger 415 is fluidly
sealed to the inner surface of dispensing chamber housing 425.
Dispensing chamber housing 425 surrounds the dispensing chamber
405. Typically, dispensing chamber housing 425 has a cylindrical
shape. As such, dispensing chamber 405 also has a cylindrical
shape. In tip segment 205, assembly 555 includes any number of
components as previously described.
[0038] Needle 210 is fluidly coupled to dispensing chamber 405. In
such a case, a substance contained in dispensing chamber 405 can
pass through needle 210 and into an eye. Temperature control device
450 at least partially surrounds dispensing chamber housing 425. In
this case, temperature control device 450 is adapted to heat and/or
cool dispensing chamber housing 425 and any substance contained in
dispensing chamber 405. Interface 530 connects temperature control
device 450 with tip interface connector 520.
[0039] The components of tip segment 205, including dispensing
chamber housing 425, temperature control device 450, and plunger
415 are at least partially enclosed by tip segment housing 215. In
one embodiment consistent with the principles of the present
invention, plunger 415 is sealed to the interior surface of
dispensing chamber housing 425. This seal prevents contamination of
any substance contained in dispensing chamber 405. For medical
purposes, such a seal is desirable. This seal can be located at any
point on plunger 415 or dispensing chamber housing 425.
[0040] In limited reuse assembly 250, power source 310 provides
power to actuator 515. An interface (not shown) between power
source 310 and actuator 515 serves as a conduit for providing power
to actuator 515. Actuator 515 is connected to actuator shaft 510.
When actuator 515 is a stepper motor, actuator shaft 510 is
integral with actuator 515. Mechanical linkage interface 545 is
connected to actuator shaft 510. In this configuration, as actuator
515 moves actuator shaft 510 upward toward needle 210 mechanical
linkage interface 545 also moves upward toward needle 210.
[0041] Controller 305 is connected via interface 535 to limited
reuse assembly interface connecter 525. Limited reuse assembly
interface connecter 525 is located on a top surface of limited
reuse assembly housing 255 adjacent to mechanical linkage interface
545. In this manner, both limited reuse assembly interface
connector 525 and mechanical linkage interface 545 are adapted to
be connected with tip interface connector 520 and plunger interface
420 respectively.
[0042] Controller 305 and actuator 515 are connected by an
interface (not shown). This interface (not shown) allows controller
305 to control the operation of actuator 515. In addition, an
interface (not shown) between power source 310 and controller 305
allows controller 305 to control operation of power source of 310.
In such a case, controller 305 may control the charging and the
discharging of power source 310 when power source 310 is a
rechargeable battery.
[0043] Controller 305 is typically an integrated circuit with
power, input, and output pins capable of performing logic
functions. In various embodiments, controller 305 is a targeted
device controller. In such a case, controller 305 performs specific
control functions targeted to a specific device or component, such
as a temperature control device or a power supply. For example, a
temperature control device controller has the basic functionality
to control a temperature control device. In other embodiments,
controller 305 is a microprocessor. In such a case, controller 305
is programmable so that it can function to control more than one
component of the device. In other cases, controller 305 is not a
programmable microprocessor, but instead is a special purpose
controller configured to control different components that perform
different functions. While depicted as one component in FIG. 5,
controller 305 may be made of many different components or
integrated circuits.
[0044] Tip segment 205 is adapted to mate with or attach to limited
reuse assembly 250 as previously described. In the embodiment of
FIG. 5, plunger interface 420 located on a bottom surface of
plunger 415 is adapted to mate with mechanical linkage interface
545 located near a top surface of limited reuse assembly housing
255. In addition, tip interface connector 520 is adapted to connect
with limited reuse assembly interface connector 525. When tip
segment 205 is connected to limited reuse assembly 250 in this
manner, actuator 515 and actuator shaft 510 are adapted to drive
plunger 415 upward toward needle 210. In addition, an interface is
formed between controller 305 and temperature control device 450. A
signal can pass from controller 305 to temperature control device
450 through interface 535, limited reuse assembly interface
connector 525, tip interface connector 520, and interface 530.
[0045] In operation, when tip segment 205 is connected to limited
reuse assembly 250, controller 305 controls the operation of
actuator 515. Actuator 515 is actuated and actuator shaft 510 is
moved upward toward needle 210. In turn, mechanical linkage
interface 545, which is mated with plunger interface 420, moves
plunger 415 upward toward needle 210. A substance located in
dispensing chamber 405 is then expelled through needle 210.
[0046] In addition, controller 305 controls the operation of
temperature control device 450. Temperature control device 450 is
adapted to heat and/or cool an outside surface of dispensing
chamber housing 425. Since dispensing chamber housing 425 is at
least partially thermally conductive, heating or cooling dispensing
chamber housing 425 heats or cools a substance located in
dispensing chamber 405. Temperature information can be transferred
from thermal sensor 460 through interface 530, tip interface
connector 520, limited reuse assembly interface connector 525, and
interface 535 back to controller 305. This temperature information
can be used to control the operation of temperature control device
450. When temperature control device 450 is a heater, controller
305 controls the amount of current that is sent to temperature
control device 450. The more current sent to temperature control
device 450, the hotter it gets. In such a manner, controller 305
can use a feed back loop utilizing information from thermal sensor
460 to control the operation of temperature control device 450. Any
suitable type of control algorithm, such as a proportional integral
derivative (PID) algorithm, can be used to control the operation of
temperature control device 450.
[0047] FIGS. 6-16 are cross section views of various plunger and
mechanical linkage interface designs according to the principles of
the present invention. In FIGS. 6-16, a plunger 415 is disposed in
dispensing chamber housing 425. Dispensing chamber 405 is adjacent
to one face of plunger 415. Mechanical linkage interface 545 has a
mating surface 605 on its distal end that mates with plunger
interface 420. In the various designs depicted in FIGS. 6-16,
plunger interface 420 and mating surface 605 of mechanical linkage
interface 545 fit together without locking. As mechanical linkage
interface 545 contacts plunger interface 420 and moves in a
direction towards dispensing chamber 405, plunger 415 is moved in a
direction towards dispensing chamber 415. In this manner,
translation of mechanical linkage interface 545 results in
translation of plunger 415 only in a direction towards dispensing
chamber 405. As plunger 415 moves, a substance, for example, a
drug, in dispensing chamber 405 is expelled through the needle (not
shown). When mechanical linkage interface 545 is retracted or moved
away from dispensing chamber 405, plunger 415 does not
substantially move. In other words, plunger 415 can only be moved
in one direction--towards dispensing chamber 405. This results in a
smooth delivery of the substance without reflux. When the needle
(not shown) is removed from the eye, the plunger remains
substantially stationary thus preventing reflux.
[0048] In FIG. 6, plunger 415 includes an o-ring 615. O-ring 615
seals against an interior surface of dispensing chamber housing
425. In this manner, a sterile seal is maintained thus preventing
contamination of the substance in dispensing chamber 405. Plunger
415 may be made of any suitable material, such as, for example,
glass, stainless steel, or a polymer. O-ring 615 is typically made
of rubber or a polymer. Mating surface 605 is substantially in the
shape of half a sphere. Plunger interface 420 is configured to
receive mating surface 605, and substantially align mechanical
linkage interface 545 with plunger 415. The embodiment of FIG. 7 is
similar to that of FIG. 6 except FIG. 7 has two orings 705 and
710.
[0049] In the embodiment of FIG. 8, a ball joint is included on one
end of mechanical linkage interface 545. The ball joint includes
ball 805 which is rotatably coupled to a shaft 810. Shaft 810 is
rigidly connected to an actuator shaft (not shown). Ball 805 is
rigidly coupled to mechanical linkage interface 545. In this
embodiment, mechanical linkage interface 545 can pivot with respect
to actuator shaft 810. Ball 805 is free to rotate with respect to
actuator shaft 810 resulting in the movement of mechanical linkage
interface in an area defined by a cone. The ball joint allows
greater freedom of movement and a better translation of force from
mechanical linkage interface 545 to plunger 415 over a wider range
of positions. The ball joint allows for three dimensional movement
of mechanical linkage interface 545, whereas the embodiment of FIG.
7, for example, does not. This can lead to improved coupling
between mechanical linkage interface 545 and plunger 415.
[0050] In FIG. 9, surface 615 of mechanical linkage interface 545
has a lip that mates with a flat surface on plunger interface 420.
The hemispherical mating surface 605 of mechanical linkage
interface 545 mates with the bowl-like depression that comprises
part of plunger interface 420. The configuration of FIG. 9 is yet
another example of an embodiment of the present invention in which
mating surface 605 of mechanical linkage interface 545 is designed
to mate with plunger interface 420 so that force can be transferred
effectively from mechanical linkage interface 545 to plunger 415.
This configuration, like the other configurations depicted in FIGS.
6-16, properly aligns mechanical linkage interface 545 and plunger
415. This helps to prevent mechanical linkage interface 545 from
binding or compressing plunger 415 against an interior surface of
dispensing chamber housing 425.
[0051] The plunger 415 of FIG. 9 also includes an annular ridge 915
that forms a seal between plunger 415 and the interior surface of
dispensing chamber housing 425. In FIG. 9, plunger 415 is made of a
rubber or polymer material, and annular ridge 915 is integral with
plunger 415. Annular ridge 915 functions like o-ring 615 and
reduces the seal contact surface.
[0052] In FIG. 10, plunger interface 420 is a flat surface.
Likewise, mating surface 605 of mechanical linkage interface 545 is
also a flat surface. Because of the location of dispensing chamber
housing 425 with respect to plunger 415 (plunger 415 is disposed
within dispensing chamber housing 425), it has been found that a
pair of flat surfaces (embodied in plunger interface 420 and mating
surface 605) provide proper alignment of mechanical linkage
interface 545 and plunger 415. This pair of flat surfaces allows
for effective transfer of motion from mechanical linkage interface
545 to plunger 415. In addition, mechanical linkage interface 545
has a disc-like end terminating at mating surface 605. The diameter
of this disc is greater than the diameter of the remainder of
mechanical linkage interface 545. Such a configuration decreases
the amount of material needed to make mechanical linkage interface
545 and thus decreases weight.
[0053] In FIG. 11, plunger 415 utilizes o-ring 615 to seal itself
against the interior surface of dispensing chamber housing 425.
Plunger interface 420 mates with mating surface 605 on mechanical
linkage interface 545. Mating surface 605 is substantially conical
in shape with a rounded distal surface. The embodiment of FIG. 11
is an example of one of many different configurations that are
within the scope of the present invention.
[0054] In the embodiment of FIG. 12, plunger interface and mating
surface 605 of mechanical linkage interface 545 are each flat
surfaces. Plunger 415 has two annular ridges 915, 920 that seal
plunger 415 against the interior surface of dispensing chamber
housing 425. Instead of o-rings or other sealing mechanisms,
annular ridges 915, 920 perform the sealing function. Annular
ridges 915, 920 are integral with plunger 415.
[0055] In FIG. 13, mechanical linkage interface 545 is tapered as
shown. The end of mechanical linkage interface 545 that is closest
to mating surface 605 has a smaller diameter than the end of
mechanical linkage interface 545 that is furthest from mating
surface 605. This taper can help in aligning mechanical linkage
interface with the plunger 425.
[0056] In FIG. 14, plunger 415 is over molded onto a shaft 1405.
Shaft 1405 is generally cylindrical in shape with a middle diameter
that is less than a diameter on the distal and proximal ends of
shaft 1405. Plunger interface 420 is a flat surface on the proximal
end of shaft 1405. Mating surface 605 of mechanical linkage
interface 545 is also a flat surface. Shaft 1415 is typically made
of a rigid material such as stainless steel. Plunger 415 is made of
a rubber or polymer material. In FIG. 15, plunger 415 has two
annular ridges.
[0057] In FIG. 16, the distal end of shaft 1605 has a lip over
which plunger 415 can be applied. Plunger 415 can be press fitted
onto shaft 1605 and is retained in place by the lip on the distal
end of shaft 1605. This allows for easier assembly. Instead of over
molding plunger 415 onto a shaft, plunger 415 can be manufactured
as a separate part and pushed onto the distal end of shaft
1605.
[0058] The various configurations of FIGS. 6-16 show examples of
embodiments of the present invention. Other combinations of
mechanical linkage interface 545 and plunger 415 are within the
scope of the present invention. In addition, other surface shapes
may be employed as mating surface 605 on mechanical linkage
interface 545. Complementary surface shapes can comprise plunger
interface 420.
[0059] FIGS. 17-18 are cross section views of two subassemblies
according to the principles of the present invention. Each of these
subassemblies depicts the path from the actuator 515 to the needle
210. FIG. 18 depicts a mechanical linkage interface 545 that is
rigidly connected to actuator shaft 510, while FIG. 19 depicts a
mechanical linkage assembly 545 with a ball joint 805.
[0060] In FIG. 17, actuator 515 has an actuator shaft 510 that is
rigidly connected to mechanical linkage interface 545. Mechanical
linkage interface mates with plunger interface 420. Plunger 415 is
disposed within dispensing chamber housing 425 and is sealed
against an inside surface of dispensing chamber housing 425.
Dispensing chamber 405 is bounded by an interior surface of
dispensing chamber housing 425 and the distal face of plunger 415.
Temperature control device 450 at least partially surrounds
dispensing chamber housing 425. Needle 210 is fluidly coupled to
dispensing chamber 405.
[0061] In FIG. 18, actuator 515 has an actuator shaft 510 that is
rigidly connected to shaft 810. Mechanical linkage interface 545 is
rotatably connected to shaft 810 via ball joint 805. Mechanical
linkage interface mates with plunger interface 420. Plunger 415 is
disposed within dispensing chamber housing 425 and is sealed
against an inside surface of dispensing chamber housing 425.
Dispensing chamber 405 is bounded by an interior surface of
dispensing chamber housing 425 and the distal face of plunger 415.
Temperature control device 450 at least partially surrounds
dispensing chamber housing 425. Needle 210 is fluidly coupled to
dispensing chamber 405.
[0062] In FIGS. 17 and 18, actuator 515 drives actuator shaft 510
upward (in a direction towards needle 210). In turn, mechanical
linkage interface 545 is also driven upward. When mechanical
linkage interface 545 is mated with plunger interface 420, plunger
420 is also moved upward. A substance contained in dispensing
chamber 405 is expelled through needle 210. In this manner, motion
and force is transferred from actuator shaft 510 to mechanical
linkage interface 545 to plunger 545.
[0063] When dispensing chamber 405 contains a drug that is to be
delivered into an eye, the various configurations of FIGS. 6-18
each eliminate reflux when the needle is removed from the eye.
Motion of the plunger 415 is in a single direction (a direction
that expels the drug in dispensing chamber 405). When mechanical
linkage interface 545 is moved in a direction away from needle 210,
for example, after the drug has been injected into the eye, the
plunger 415 remains in place. Since plunger 415 is not rigidly
connected to mechanical linkage interface 545, plunger 415 is not
retracted as mechanical linkage interface 545 is retracted.
[0064] FIG. 19 is a method of operating an ophthalmic medical
device according to the principles of the present invention. The
method of FIG. 19 is one way in which the tip segment and limited
reuse assembly may be operated. In 1910 the mechanical linkage
interface is advanced until it contacts the plunger. In one
embodiment of the present invention, the controller directs the
actuator to move the shaft to which the mechanical linkage
interface is attached. In 1920, the mechanical linkage interface is
further advanced to advance the plunger to expel the substance that
is contained in the dispensing chamber. In 1930, the mechanical
linkage interface is retracted without retracting the plunger. This
prevents reflux of the substance. Depending on the composition of
the materials that are used, some friction force may be present
between the mating surface of the mechanical linkage interface and
the plunger interface. However, the mating surface of the
mechanical linkage interface and plunger interface are designed to
disengage very easily, substantially preventing the transfer of
force or motion from the mechanical linkage interface to the
plunger when the mechanical linkage interface is retracted.
[0065] FIG. 20 is a method of operating an ophthalmic medical
device according to the principles of the present invention. The
method of FIG. 20 is one way in which the tip segment and limited
reuse assembly may be operated. In 2010, a connection is recognized
between the disposable tip segment and the limited reuse assembly.
In 2020, a temperature control device is activated to alter the
temperature of a substance contained in the dispensing chamber. In
one embodiment of the present invention, an input is received from
the thermal sensor, and the input is used to control the
temperature control device. In 2030, dosage information is read. In
2040, in response to the dosage information, the mechanical linkage
interface is advanced to advance the plunger to expel the substance
from the dispensing chamber. In 2050, the mechanical linkage
interface is retracted without retracting the plunger to prevent
reflux of the substance. In 2060, the disposable tip segment is
prevented from being reused. In 2070, the removal of the disposable
tip segment from the limited reuse assembly is recognized.
[0066] From the above, it may be appreciated that the present
invention provides an improved system and methods for delivering
precise volumes of a substance into an eye. The present invention
provides a single use, disposable delivery device tip segment that
is capable of delivering a precise dosage. The tip segment
interfaces with a limited reuse assembly. The disposable tip
segment has a plunger interface that mates with a mechanical
linkage interface. The plunger interface and mechanical linkage
interface are designed to prevent reflux of the substance when the
needle is removed from the eye. The present invention is
illustrated herein by example, and various modifications may be
made by a person of ordinary skill in the art.
[0067] While the present invention is described in the context of a
single-use drug delivery device, the present invention encompasses
any single-use medical device that interfaces with a source of
electric power. Other embodiments of the invention will be apparent
to those skilled in the art from consideration of the specification
and practice of the invention disclosed herein. It is intended that
the specification and examples be considered as exemplary only,
with a true scope and spirit of the invention being indicated by
the following claims.
* * * * *