Surgery – Diagnostic testing – Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
2001-05-11
2003-07-08
Lazarus, Ira S. (Department: 3749)
Surgery
Diagnostic testing
Measuring or detecting nonradioactive constituent of body...
C604S019000, C604S027000, C604S046000, C604S048000, C600S365000, C600S362000, C600S578000, C600S576000, C606S189000, C606S186000, C606S167000
Reexamination Certificate
active
06591124
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to interstitial fluid monitoring equipment and is particularly directed to a portable glucose monitoring system of the type which could be used at home by consumers. The invention is specifically disclosed as a home glucose monitoring system that uses an array of microneedles to painlessly sample interstitial fluid and provide an indication of the glucose concentration.
BACKGROUND OF THE INVENTION
Topical delivery of drugs and topical sampling of biological fluids are very useful methods for achieving either systemic or localized pharmacological effects, or for diagnostics, although there is a main challenge involved in providing sufficient fluid penetration across the skin. Skin consists of multiple layers, in which the stratum corneum layer is the outermost layer, then a viable epidermal layer, and finally a dermal tissue layer. The thin layer of stratum corneum represents a major barrier for chemical penetration through the skin. The stratum corneum is responsible for 50%-90% of the skin barrier property, depending upon the analyte's water solubility and molecular weight.
An alternative to the use of hypodermic needles for drug delivery by injection is disclosed in U.S. Pat. No. 3,964,482 (by Gerstel), in which an array of either solid or hollow microneedles is used to penetrate through the stratum corneum and into the epidermal layer. Fluid is dispensed either through the hollow microneedles or through permeable solid projections, or perhaps around non-permeable solid projections that are surrounded by a permeable material or an aperture. A membrane material is used to control the rate of drug release, and the drug transfer mechanism is absorption.
Other types of microneedle structures are disclosed in WO 98/00193 (by Altea Technologies, Inc.), and in WO 97/48440, WO 97/48441, and WO 97/48442 (by Alza Corp.). In addition, WO 96/37256 discloses another type of microblade structure. Moreover, WO 99/64580 and WO 00/74763 A2, by Georgia Tech Research Corporation, disclose various microneedle structures and methods for manufacturing the same.
The use of microneedles has one great advantage in that intracutaneous drug delivery or drug sampling can be accomplished without pain and without bleeding. As used herein, the term “microneedles” refers to a plurality of elongated structures that are sufficiently long to penetrate through the stratum corneum skin layer and into the epidermal layer. In general, the microneedles are not to be so long as to penetrate into the dermal layer, although there are circumstances where that would be desirable.
A portable microneedle device that can extract or inspect interstitial fluid from skin and provide an instantaneous readout on a display would be very useful, particularly for diabetics who desire to know in real time their glucose level (concentration). It would be very advantageous to provide one or more self-contained sampling devices based upon microneedles that make available a “microneedle patch” or “microneedle strip” that a human user can touch (with a finger, for example), then press an actuator button or switch to inspect or extract a fluid sample, and finally that automatically display the results, in real time or near-real time. It would be further desirable if the microneedle portions were disposable, designed for a single use.
SUMMARY OF THE INVENTION
Accordingly, it is an advantage of the present invention to provide a fluid sampling apparatus that includes a plurality of microneedles accessible on a first surface, a manually-operated pumping apparatus accessible on a second surface, and a reservoir that is in hydraulic communication with both the microneedles and the pumping apparatus. The reservoir receives fluid that flows through the plurality of microneedles upon manual actuation of the pumping apparatus.
It is another advantage of the present invention to provide a fluid sampling apparatus that includes a plurality of solid, coated microneedles accessible on a first surface, a member having a first end near the coated microneedles and which extends to a second end distal from the coated microneedles, and at least one electrode positioned on the extending member, in which the electrodes are in communication with the coated microneedles. The solid microneedles are coated on an exterior surface, and the coating on the microneedles acts as an electrochemical sensor of a property of a fluid of a biological barrier such as skin. When the solid microneedles make contact with the biological barrier, the electrochemical sensor generates an electrical signal in response to the fluid property.
It is a further advantage of the present invention to provide yet another fluid sampling apparatus that includes an attachable/detachable portion that has a plurality of microneedles, a reservoir, an optical sensor pad, and an optical window; and a main body portion that includes a receptacle to receive the attachable/detachable portion such that, when in position, the optical window faces the main body portion and the plurality of microneedles are accessible, a light source and light detector, and a manually-operated control actuator mounted on a surface of the main body portion that causes fluid to flow proximal to the plurality of microneedles. The reservoir receives fluid that flows through the plurality of microneedles upon manual operation of the control actuator, and the optical sensor pad exhibits a change in a physical property that is detected by the light detector as the light source shines light upon the optical sensor pad.
It is a still further advantage of the present invention to provide still another fluid sampling apparatus is provided, which includes an attachable/detachable portion that has a plurality of microneedles, a reservoir, an electrochemical sensor pad, and at least one electrode in communication with the sensor pad; and a main body portion that includes a receptacle to receive the attachable/detachable portion such that, when in position, the electrodes face the main body portion and the plurality of microneedles are accessible, an electron sensor, and a manually-operated pumping apparatus accessible on a surface of the main body portion. The reservoir receives fluid that flows through the plurality of microneedles upon manual actuation of the pumping apparatus, and the electrochemical sensor pad exhibits a change in a physical property that is detected by the electrodes, which output an electrical signal. The electron sensor is in communication with the electrodes and generates an output signal in response to the electrical signal.
It is still another advantage of the present invention to provide a fluid sampling apparatus that includes a plurality of microneedles and an associated substrate that is in mechanical communication with a manually operable plunger, a housing that contains a variable volume chamber and which contains a flexible membrane that deflects upon movement of the plunger, in which the membrane's deflection causing a variation in the volume of the chamber, and an output port that is in hydraulic communication with the variable volume chamber. Upon actuation of the plunger in one direction, the microneedles are pushed into and pierce a biological barrier such as skin. Upon actuation of the plunger in a second, opposite direction, fluid from the biological barrier is withdrawn into the variable volume chamber and thereby directed to the output port.
It is yet a further advantage of the present invention to provide a replaceable cartridge that includes a plurality of microneedle strips attached to a movable substrate of material; in which each of the microneedle strips includes a plurality of microneedles accessible to a user, a sensor that is in communication with a fluid that flows through the microneedles, and a signal transducer that is in communication with the sensor. The signal transducer of a first of the plurality of microneedle strips generates an electrical signal that is communicated to an output port. The movable substrat
Arias Francisco
Gartstein Vladimir
Huang Chow Chi
Jevtitch Milan Marcel
Owens Grover David
Hersko Bart S.
Lazarus Ira S.
Nguyen Tu C.
The Procter & Gamble & Company
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