U.S. patent application number 13/419968 was filed with the patent office on 2012-09-20 for instrument and methods for filling an implanted drug pump.
Invention is credited to Sean Caffey, Mark Humayun, Fukang Jiang, Changlin Pang, Raymond Peck, Jason Shih, Yu-Chong Tai.
Application Number | 20120234433 13/419968 |
Document ID | / |
Family ID | 46028124 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120234433 |
Kind Code |
A1 |
Shih; Jason ; et
al. |
September 20, 2012 |
INSTRUMENT AND METHODS FOR FILLING AN IMPLANTED DRUG PUMP
Abstract
A tool for refilling an implantable pump having at least one
reservoir. The tool includes a plurality of independent fluid
channels; a fluid reservoir in fluid communication with a first one
of the fluid channels; at least one pump fluidly coupled to the
fluid channels, the at least one pump and the independent fluid
channels differing from each other in number, wherein (i) a pump is
configured to apply positive pressure to the first fluid channel so
as to drive fluid from the fluid reservoir therethrough, and (ii) a
pump is configured to apply negative pressure to the second fluid
channel; and a connector for removably connecting the fluid
channels to the at least one reservoir.
Inventors: |
Shih; Jason; (Yorba Linda,
CA) ; Caffey; Sean; (Manhattan Beach, CA) ;
Humayun; Mark; (Glendale, CA) ; Jiang; Fukang;
(Pasadena, CA) ; Pang; Changlin; (Pasadena,
CA) ; Peck; Raymond; (Los Angeles, CA) ; Tai;
Yu-Chong; (Pasadena, CA) |
Family ID: |
46028124 |
Appl. No.: |
13/419968 |
Filed: |
March 14, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61452399 |
Mar 14, 2011 |
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Current U.S.
Class: |
141/4 ;
141/37 |
Current CPC
Class: |
A61M 5/14276
20130101 |
Class at
Publication: |
141/4 ;
141/37 |
International
Class: |
B65B 31/00 20060101
B65B031/00 |
Claims
1. A tool for refilling an implantable pump having at least one
reservoir, the tool comprising: a plurality of independent fluid
channels; a fluid reservoir in fluid communication with a first one
of the fluid channels; at least one pump fluidly coupled to the
fluid channels, the at least one pump and the independent fluid
channels differing from each other in number, wherein (i) a pump is
configured to apply positive pressure to the first fluid channel so
as to drive fluid from the fluid reservoir therethrough, and (ii) a
pump is configured to apply negative pressure to a second fluid
channel; and a connector for removably connecting the fluid
channels to the at least one reservoir.
2. The tool of claim 1, wherein there is one pump and at least two
independent fluid channels, the pump being configured to generate
suction through a first one of the channels and to drive a fluid
through a second one of the channels.
3. The tool of claim 2, where there is a third independent fluid
channel connected to the pump, wherein the pump is configured to
drive a second fluid through the third fluid channel.
4. The tool of claim 1, further comprising a sensor associated with
each of the channels for monitoring at least one parameter relating
to liquid flowing therethrough.
5. The tool of claim 4, wherein the sensor is a flow sensor and the
parameter is a flow rate of the liquid.
6. The tool of claim 4, wherein the sensor is a pressure sensor and
the parameter is pressure in the channels.
7. The tool of claim 4, further comprising governing circuitry
preventing the monitored parameter from exceeding or falling below
a predefined level.
8. The tool of claim 7, further comprising first and second valves,
responsive to the governing circuitry, for controlling fluid flow
through the first and second fluid channels, respectively.
9. A tool for refilling an implantable pump having a reservoir, the
tool comprising: a refilling kit comprising first and second
independent fluid channels connectable at first ends thereof to the
reservoir; and a base unit comprising at least one pump, a sensor
for monitoring at least one parameter relating to flow through the
fluid channels, and feedback circuitry for controlling flow through
the fluid channels based on the at least one monitored parameter,
wherein the base unit is removably connectable to second ends of
the fluid channels.
10. The tool of claim 9, wherein the refilling kit is connectable
to the reservoir by means of a needle configured for entering the
reservoir, the needle having separate lumens each fluidly coupled
to one of the fluid channels.
11. The tool of claim 9, further comprising a locking system
associated with the refilling kit for preventing injection of an
unapproved fluid into the reservoir.
12. A method of filling an implantable drug-delivery pump having at
least one reservoir, the method comprising the steps of: fluidly
coupling a plurality of independent fluid channels to the
reservoir; and operating a single pump to (i) purge the reservoir
via at least a first of the plurality of fluid channels and (ii)
pump fluid into the purged reservoir using a second of the
plurality of fluid channels.
13. The method of claim 12, wherein the pump generates suction
through the first one of the fluid channels and drives a fluid
through the second one of the fluid channels.
14. The method of claim 13, wherein the purging step comprises
causing the single pump to pump fluid into the reservoir through a
third independent fluid channel and thereafter suction the fluid
from the reservoir via the first fluid channel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of, and
incorporates herein by reference in its entirety, U.S. Provisional
Patent Application No. 61/452,399, which was filed on Mar. 14,
2011.
FIELD OF THE INVENTION
[0002] In various embodiments, the present invention relates,
generally, to implantable drug pump devices, and in particular to
systems and methods for refilling such devices.
BACKGROUND
[0003] Medical treatment often requires the administration of a
therapeutic agent (e.g., medicament, drugs, etc.) to a particular
part of a patient's body. As patients live longer and are more
frequently diagnosed with chronic and often debilitating ailments,
the result will be an increase in the need to place protein
therapeutics, small-molecule drugs and other medications into
targeted areas throughout the body. Some maladies, however, are
difficult to treat with currently available therapies and/or
require administration of drugs to anatomical regions to which
access is difficult to achieve.
[0004] A patient's eye is a prime example of a difficult-to-reach
anatomical region, and many vision-threatening diseases, including
retinitis pigmentosa, age-related macular degeneration (AMD),
diabetic retinopathy, and glaucoma, are incurable and yet difficult
to treat with currently available therapies. For example, oral
medications have systemic side effects; topical applications may
sting and engender poor compliance; injections require a medical
visit, can be painful and risk infection; and sustained-release
implants must typically be removed after their supply is exhausted
(and generally offer limited ability to change the dose in response
to the clinical situation). Another example is cancer, such as
breast cancer or meningiomas, where large doses of highly toxic
chemotherapies such as rapamycin or irinotecan (CPT-11) are
typically administered to the patient intravenously, resulting in
numerous undesired side effects outside the targeted area. Yet
another example is drug delivery to the knee, where drugs often
have difficulty penetrating the avascular cartilage tissue for
diseases such as osteoarthritis.
[0005] Implantable drug delivery systems, which may have a
refillable drug reservoir, cannula and check valve, etc., generally
allow for controlled delivery of pharmaceutical solutions to a
specified target. As drug within the drug reservoir depletes, the
physician can refill the reservoir with, for example, a syringe,
via a refill port while leaving the device implanted within the
patient's body. This approach can minimize the surgical incision
needed for implantation and avoids future or repeated invasive
surgery or procedures.
[0006] Conventionally, the drug pump is refilled manually using,
for example, a handheld syringe. This approach can be both
inconvenient and dangerous. It is typically difficult to monitor
the pressure in the syringe, and a large pressure may be generated
inadvertently particularly when small volumes are involved and the
syringe plunger is of small diameter. Excessive pressures can
damage the pump and/or cause improper drug expulsion. Additionally,
refilling the implantable pump may represent a difficult manual
task. For example, the pump's refill port, which is usually located
on the pump surface to facilitate post-implantation access, may be
inaccessible or inconvenient to access due to the recipient's
internal anatomy. This makes the refill procedure uncomfortable for
the recipient and, once again, risks damage to the pump. Refilling
difficulties are especially acute if the therapeutic procedure
involves a multiple-drug administration which requires several
cycles of needle insertion and withdrawal as different fluids are
removed and injected into the pump, causing stress for both the
patient and doctor and creating wear on the refill port.
[0007] Consequently, there is a need for a refilling system that
can monitor the pressure during drug administration and reduce the
insertion frequency into the implanted pump.
SUMMARY
[0008] In accordance with various embodiments of the invention
described herein, a dedicated instrument is used to automatically
facilitate a filling or refilling therapeutic procedure via, for
example, a self-sealing needle-accessible refill port in an
implanted drug pump. The procedure may include, for example,
emptying, rinsing, and filling the drug reservoir. An instrument in
accordance with the current invention may be configured such that
only a single needle insertion in the fluid access refill port is
required to direct multiple fluids to the implanted pump.
Additionally, the instrument may include a valve, a pressure sensor
and/or a flow sensor to detect and control the pressure therein.
The automation and/or pressure-control of the refilling process
protects pump components (e.g., the refill port or the reservoir)
from potential damage and ensures reliable and repeatable drug
filling.
[0009] Accordingly, in one aspect, the invention pertains to a tool
for refilling an implantable pump having at least one reservoir. In
various embodiments, the tool includes: (i) multiple independent
fluid channels, (ii) a fluid reservoir in fluid communication with
a first fluid channel, and (iii) a connector for removably
connecting the fluid channels to the at least one reservoir. The
tool may include one or more pumps that are fluidly coupled to the
fluid channels. The pump(s) may be configured to apply positive
pressure to the first fluid channel so as to drive fluid from the
fluid reservoir therethrough, and to apply negative pressure to a
second fluid channel.
[0010] The pump(s) and the independent fluid channels may differ
from each other in number. For example, when there are one pump and
at least two independent fluid channels, the pump may be configured
to generate suction through a first one of the channels and to
drive a fluid through a second one of the channels. If there is a
third independent fluid channel connected to the pump, the pump may
be configured to drive a second fluid through the third fluid
channel.
[0011] The tool may include a sensor associated with each of the
channels for monitoring at least one parameter relating to liquid
flowing therethrough. The sensor may be a flow sensor and/or a
pressure sensor and the parameter may be a flow rate of the liquid
and/or pressure in the channels, respectively.
[0012] Additionally, the tool may include governing circuitry for
preventing the monitored parameter from exceeding or falling below
a predefined level. Two valves that are responsive to the governing
circuitry may be used for controlling fluid flow through the first
and second fluid channels.
[0013] In a second aspect, the invention relates to a tool for
refilling an implantable pump having a reservoir. The tool may
include a refilling kit and a base unit. The refilling kit may have
two independent fluid channels connectable at one end thereof to
the reservoir. The base, which is removably connectable to the
other ends of the fluid channels, may include at least one pump, a
sensor for monitoring at least one parameter relating to flow
through the fluid channels, and feedback circuitry for controlling
flow through the fluid channels based on the monitored
parameter(s).
[0014] The refilling kit may be connectable to the reservoir by
means, for example, of a needle configured for entering the
reservoir. The needle may have separate lumens each fluidly coupled
to one of the fluid channels. The tool may further include a
locking system that is associated with the refilling kit for
preventing injection of an unapproved fluid into the reservoir.
[0015] In a third aspect, the invention relates to a method of
filling an implantable drug-delivery pump having at least one
reservoir. In some embodiments, the method includes the steps of:
(i) fluidly coupling multiple independent fluid channels to the
reservoir and (ii) operating a single pump to purge the reservoir
via a first one of the multiple channels and pump fluid into the
purged reservoir via a second one of the multiple fluid channels.
The pump may generate suction through the first fluid channel and
drives a fluid through the second fluid channel. The purging step
may include causing the single pump to pump fluid into the
reservoir through a third independent fluid channel and thereafter
provide suction to draw the fluid from the reservoir via the first
fluid channel.
[0016] Reference throughout this specification to "one example,"
"an example," "one embodiment," or "an embodiment" means that a
particular feature, structure, or characteristic described in
connection with the example is included in at least one example of
the present technology. Thus, the occurrences of the phrases "in
one example," "in an example," "one embodiment," or "an embodiment"
in various places throughout this specification are not necessarily
all referring to the same example. Furthermore, the particular
features, structures, routines, steps, or characteristics may be
combined in any suitable manner in one or more examples of the
technology. The headings provided herein are for convenience only
and are not intended to limit or interpret the scope or meaning of
the claimed technology.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the drawings, like reference characters generally refer
to the same parts throughout the different views. Also, the
drawings are not necessarily to scale, with an emphasis instead
generally being placed upon illustrating the principles of the
invention. In the following description, various embodiments of the
present invention are described with reference to the following
drawings, in which:
[0018] FIG. 1 schematically illustrates an implantable
drug-delivery pump;
[0019] FIG. 2A schematically illustrates a filling/refilling
instrument in accordance with an embodiment of the current
invention;
[0020] FIG. 2B schematically depicts the filling/refilling
instrument incorporating valves, sensors and a feedback system;
[0021] FIG. 2C schematically illustrates a single pump associated
with two fluid channels;
[0022] FIG. 2D schematically depicts a base unit having pumps,
sensors, valves and a feedback system and a filling/refilling kit
having fluid channels;
[0023] FIG. 3 schematically depicts the wash channel and the
filling channel merged into a single channel; and
[0024] FIG. 4 schematically depicts two lumens in the needle that
is used to puncture the drug reservoir.
DETAILED DESCRIPTION
[0025] Refer first to FIG. 1, which illustrates an
electrolysis-actuated, implantable drug-delivery pump 100, as
described, for example, in U.S. Ser. No. 12/463,251, the entire
disclosure of which is hereby incorporated by reference. As
illustrated, the implantable drug pump 100 has a cannula 102 and a
pair of chambers 104, 106 bounded by an envelope 108. The top
chamber 104 defines a drug reservoir that contains the drug to be
administered in liquid form, and the bottom chamber 106 contains a
liquid which, when subjected to electrolysis using electrolysis
electrodes 110, evolves a gaseous product. The two chambers are
separated by a corrugated diaphragm 112. The cannula 102 connects
the top drug chamber 104 with a check valve 114 inserted at the
site of administration. The envelope 108 resides within a shaped
protective shell 116 made of a flexible material (e.g., a bladder
or collapsible chamber) or a relatively rigid biocompatible
material (e.g medical-grade polypropylene). Control circuitry 118,
a battery 120 and an induction coil 122 for power and data
transmission are embedded under the parylene chambers (i.e.,
between the bottom wall of the electrolyte chamber 106 and the
floor of the shell 116). One or more refill ports 124 are in fluid
communication with the drug reservoir 104 and permit the drug
reservoir 104 to be refillable by inserting, for example, a refill
needle (not shown) therethrough. The refill port 124 may include a
self-sealing material such that the needle can puncture the top
surface thereof and the surface reseals itself upon removal of the
needle. The self-sealing material may be able to withstand multiple
punctures by the needle, and is biocompatible. Through the refill
port 124, the existing fluid in the reservoir can be removed, the
reservoir washed, and a filling/refilling solution injected.
Certain embodiments of the invention involve an external device
that can be interfaced to the liquid containing reservoir for the
automatic filling/refilling of the reservoir.
[0026] FIG. 2A depicts an instrument 200 that interfaces with and
refills, for example, the implantable drug-delivery pump 100 as
show in FIG. 1 in accordance with an embodiment of the current
invention. The instrument 200 may include a needle 210 piercing
through the surface of the refill port 124 to facilitate the fluid
communication between the drug reservoir 104 in the implantable
pump 100 and the instrument 200 that has one or more independent
fluid channels 212, 214, 216. In various embodiments, the refilling
process begins with removing or aspirating an expired and/or
remnant fluid from the drug reservoir 104 via the lumen 218 of the
needle 210 and the first channel 212 of the instrument 200 using,
for example, vacuum suction generated by the first pump 220. A wash
solution in the second channel 214, handled by the associated
second pump 222, is then drawn to the drug reservoir 104 via the
lumen 218 of the needle 210 to wash away and rinse the drug
reservoir 104; the waste from the wash-removal process is collected
using the first waste channel 212 and its connected pump 220, as
described above. The wash-removal process may be repeated as many
times as necessary for effectiveness. After the final waste-removal
step is complete, the drug refilling solution in the third channel
216 may be injected into the drug reservoir 104 using the
associated third pump 224. As described above, during the
filling/refilling process, only a single needle insertion in the
fluid access refill port is required; this thus reduces the needle
insertion frequency into the drug reservoir 104 of the implanted
pump 100. Additionally, if a refill procedure involves directing
multiple fluids to the implanted pump 100, a single needle
insertion using the instrument 200 may suffice. In one embodiment,
a drug container 226 (e.g., a vial) directly connects to the third
channel 216 such that the drug flows out of the container 226 into
the drug reservoir 104 via the third channel 216, without the risks
of contamination or other human error introduced when performing
the intermediate step of delivering drug from a vial to the drug
reservoir 104 using a needle or other delivery means.
[0027] In some embodiments, as illustrated in FIG. 2B, the fluid
channels 212, 214, 216 connect to the needle 210 via valves 238,
240, 242. Alternatively, or additionally, the valves 238, 240, 242
may be integral with the fluid channels 212, 214, 216, and may be
located anywhere along the channels. Prior to a filling/refilling
process, all three valves 238, 240, 242 are initially closed when
the needle 210 is inserted into the drug reservoir 104 through the
refill port so that the outlet of the needle 210 is in fluid
communication with the drug chamber 104 but is isolated from the
rest of the system by the valves. In a first step, valve 238
connected to the first waste channel 212 is opened and any fluid
that is left in the reservoir 104 is removed using, for example,
suction by activating the associated pump 220. In a second step,
valve 238 is then closed and valve 240 is opened to pump a wash
solution into the drug chamber 104 via the solution channel 214;
the waste from the wash step is collected using the method
described in step one. In one embodiment, the suction and wash
steps are alternately and repeatedly performed (by alternately
closing and opening valves 238 and 240). Alternatively, valve 238
may be left open during step two such that the suction is left on
to perform a continuous rinse of the drug reservoir 104. In either
case, after the final waste-removal step is complete, valves 238
and 240 are closed and valve 242 is opened to fill the reservoir
104 with the drug solution via the solution channel 216 (step
three).
[0028] In various embodiments, the refill instrument 200 includes
flow sensors 246 and/or pressure sensors 248 to monitor and control
the flow rate and/or pressure, respectively, of the fluid injection
and suction in each channel 212, 214, 216. For example, flow
sensors 246, based upon thermal effects, time-of-flight, and/or
pressure, as explained further below, may be employed within the
channels to sense the fluidic flow. In one embodiment, flow sensors
246 based on thermal effects use a resistive heater to locally heat
the fluid flowing in proximity to the sensors 246. The temperature
of the flowing fluid in the channel then provides an indication of
the flow rate. For example, time-of-flight flow sensors 246
generate a tracer pulse in the fluid flowing within the channel,
and then measure the time that it takes for this pulse to traverse
a certain distance. This measured time is defined as the "time of
flight" and corresponds to the linear fluid velocity, which may be
translated into a volumetric flow rate. In another embodiment, flow
sensors 246 utilize pressure sensing and are employed within the
fluid channel to measure the pressure therein and, based thereon,
to increase or reduce the fluid flow rate through the channels when
necessary. The pressure-based flow sensors 246 may function in any
of a variety of ways; for example, capacitive, piezoresistive, and
piezoelectric implementations, among others known to those of
ordinary skill in the art, may all be employed advantageously. In
various embodiments, if one or more pressure sensors 248 are placed
inside the channels 212, 214, 216, operations of the channels
associated pumps 220, 222, 224 may be adjusted to maintain an
optimal pressure or pressure range during the filling/refilling
process and thus avoid excess pressure, prevent damage to the
pumps, and unwanted ejection of drug into the patient.
[0029] A critical set of values that define the upper and lower
bounds of the safe range of pressure and/or flow rate may be
determined before the filling/refilling process. If the pressure
and/or flow rates exceed or fall below the set critical values
during the filling/refilling procedure, an alarm system may be
turned on and/or a feedback system may be initiated to control the
pressure and flow rate such that the pressure and flow rates inside
the fluid channels 212, 214, 216 and/or the drug reservoir 104
remain within safe operational values; this prevents drug expulsion
or damage to the instrument 200 and/or the drug chamber 104.
[0030] The pumps 220, 222, 224 that are in fluid communication with
the fluid channels 212, 214, 216 and handle the waste solution,
wash solution and filling/refilling solutions may be standard
mechanical pumps (e.g., gear, diaphragm, peristaltic, syringe,
etc.) or pneumatic systems that create vacuum or adjust pressure in
the individual channels. Pneumatic systems may include, but are not
limited to, vacuum generators, air compressors, pneumatic motors,
and pneumatic actuators, etc. The pumps 220, 222, 224 work
cooperatively with the flow sensors 246, pressure sensors 248
and/or valves 238, 240, 242 to control the flow rate and/or
pressure in the fluid channel 212, 214, 216 during the refilling
process. In addition, the volume of fluid may be metered to prevent
overfilling. If the drug reservoir 104 reaches full capacity such
that the internal pressure begins to rise, pumps 220, 222, 224 may
adjust the pressure such that fluid is injected less into the
reservoir 104 and/or aspirated more from the reservoir 104. In one
embodiment, the fluid injection pressure is monitored and
maintained below a critical value when a liquid is infused into the
drug reservoir 104 pneumatically. If the pressure exceeds the
critical value, a pressure-release valve (not shown) may be used to
reduce the pressure inside the channel. In another embodiment, if
the liquid is infused using a mechanical pump, the pressure may be
monitored and controlled by a pressure sensor 248 disposed at the
point of highest hydraulic pressure; a feedback system 254 (e.g.,
control circuitry) may then be used to prevent the pressure at this
point from exceeding the critical value. In general, the feedback
system 254 is typically implemented on a printed circuit board
("PCB") and may interface with the pumps 220, 222, 224 associated
with the fluid channel 212, 214, 216, the flow sensors 246, the
pressure sensors 248 and/or the valves 238, 240, 242. In response
to the measured flow rates and/or pressures in the fluid channel,
the feedback system 254 takes corrective action in order to ensure
that the flow rate and/or pressure of the drug delivered through
the channels remains within the critical range. For example, when
receiving pressure data indicating that the pressure inside the
fluid channel is too high, the feedback system 254 can
automatically adjust operation of the pumps 220, 222, 224 and/or
valves 238, 240, 242 to avoid excess pressure and/or maintain an
optimal pressure or pressure range, thus preventing harm to the
patient. The number of pumps used to drive the fluids in the
channels may be different from (e.g., less than) the number of
channels. For example, as depicted in FIG. 2C, one pump 256 may be
used to connect to the first waste and second wash channels 212,
214: while one outlet 258 of the pump 256 generates suction such
that the fluid in the drug reservoir 104 is removed, another outlet
260 of the pump 256 exerts a pressure to drive the fluid flow into
the drug reservoir 104.
[0031] The feedback system 254, pumps 220, 222, 224 that are
associated with the fluid channel, the flow sensors 246 and/or the
pressure sensors 248, the valves 238, 240, 242, and/or the channels
212, 214, 216 may be implemented as a single unit or as multiple
components. Referring to FIG. 2D, in one embodiment, the pumps 220,
222, 224, sensors 246, 248 and valves 238, 240, 242 are integrated
with the feedback system 254 to form a base unit 262 while the
fluid channels 212, 214, 216 are combined (e.g., into a single
cartridge structure) to form a filling/refilling kit 264. The
filling/refilling kit 264 may be mated with the base unit 262 and
the needle 210 at the time of use. In such implementations, the
filling/refilling kit 264 may be a single-use disposable component
that is replaced each time a new reservoir is filled. The
filling/refilling kit 264 may be provided to the end-user as a
pre-filled kit or empty. In the case of an empty filling kit, fluid
may be manually transferred to the kit 264 or the procedure may be
performed automatically by the base unit 262.
[0032] In some embodiments, an electronic or mechanical locking
system 266 is employed to prevent a user from injecting an
unapproved fluid into the reservoir. The locking system may be
based on, for example, electronic tags (e.g., RFID, barcodes, etc.)
that are associated with the filling/refilling kit 264 described
above. If improper tags are sensed, the instrument 200 may be
programmed to prevent filling.
[0033] Although described above is a three-channel system, one of
ordinary skill in the art will understand that systems may have
different numbers of channels that ultimately terminate in the
needle 210 and are within the scope of the current invention. For
example, fewer independently controlled fluid channels may be
utilized in the current invention. Referring to FIG. 3, an
exemplary system 300 uses two independently controlled fluid
channels 310, 312, where the wash channel and filling channel are
merged in a single channel 312. Therefore, instead of using a
dedicated wash solution to rinse the drug reservoir 104, the drug
solution itself can be used. As a result, two independent fluid
channels 310, 312--channel 312 for infusing the drug and channel
310 for aspirating liquid out of the reservoir 104--may
suffice.
[0034] As described above, the fluid channels may be interfaced to
a flow control system ultimately terminating in a needle 210, which
is used to pierce the access port and access the fluid reservoir
104. In one embodiment, the needle includes one lumen and all
fluids from the channels travel in and out of the single lumen, as
depicted in FIGS. 2A-2D and 3. In another embodiment, with
reference to FIG. 4, the needle includes two lumens 410, 412, which
provide two parallel, isolated paths for fluid to flow between the
channels 414, 416, 418 and the drug reservoir 104. One of these
lumens, i.e., lumen 410 may be dedicated for aspiration and the
other lumen, i.e., lumen 412, may be used to infuse liquid (e.g.,
wash and drug solutions). During the filling/refilling procedure,
all valves except valve 420 may be closed and the fluid in the
reservoir 104 is removed via flowing through lumen 410. The
reservoir 104 is then washed by opening valve 422 and pumping the
wash solution through lumen 412. The waste from the washing step
may then be removed through lumen 410. Finally, after the reservoir
104 is completely washed, valves 420 and 422 may be closed and
valve 424 is opened to fill/refill the drug reservoir via lumen
412. Again, channels 416 and 418 may be merged to a single channel
and the drug may serve as a rinse solution; this merged channel
thus delivers the same drug solution during the filling/refilling
procedure.
[0035] The terms and expressions employed herein are used as terms
and expressions of description and not of limitation, and there is
no intention, in the use of such terms and expressions, of
excluding any equivalents of the features shown and described or
portions thereof. In addition, having described certain embodiments
of the invention, it will be apparent to those of ordinary skill in
the art that other embodiments incorporating the concepts disclosed
herein may be used without departing from the spirit and scope of
the invention. Accordingly, the described embodiments are to be
considered in all respects as only illustrative and not
restrictive.
* * * * *