Surgery – Means for introducing or removing material from body for... – With means for cutting – scarifying – or vibrating tissue
Reexamination Certificate
1999-06-14
2001-02-06
Bockleman, Mark (Department: 3763)
Surgery
Means for introducing or removing material from body for...
With means for cutting, scarifying, or vibrating tissue
C424S449000, C606S186000, C600S362000, C600S583000
Reexamination Certificate
active
06183434
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a device and method for puncturing a selected layer or layers of the skin or mucosa. More particularly, the invention relates a device and method for puncturing the stratum corneum or mucosa to diminish the barrier function thereof and permit a drug to be delivered to the body or an analyte in the body to be withdrawn for monitoring. This puncturing of the stratum corneum or mucosa is minimally invasive, and can be combined with various other methods, such as use of chemical enhancers, pressure gradients, sonic gradients, temperature gradients, and the like for selectively enhancing the inward flux of a drug to the body or the outward flux of an analyte from the body.
The stratum corneum is chiefly responsible for the well-known barrier properties of skin. Thus, it is this layer of the skin that presents the greatest barrier to transdermal flux of drugs or other molecules into the body and of analytes out of the body. Mucosal tissue also presents a barrier to flux of molecules into and out of the body. The stratum corneum, the outer horny layer of the skin, is a complex structure of compact keratinized cell remnants separated by lipid domains. Compared to the oral or gastric mucosa, the stratum corneum is much less permeable to molecules either external or internal to the body. The stratum corneum is formed from keratinocytes, which comprise the majority of the epidermal cells, that lose their nuclei and become corneocytes. These dead cells comprise the stratum corneum, which has a thickness of about 10-30 &mgr;m and, as noted above, is a very resistant waterproof membrane that protects the body from invasion by exterior substances and the outward migration of fluids and dissolved molecules. The stratum corneum is continuously renewed by shedding of corneum cells during desquamination and the formation of new corneum cells by the keratinization process.
Various methods of enhancing the permeability of the stratum corneum and mucosa have been described. For example, U.S. Pat. No. 5,458,140 and U.S. Pat. No. 5,445,611 disclose using ultrasonic energy that is modulated in intensity, phase, or frequency or a combination thereof. U.S. Pat. No. 4,775,361 discloses a method of administering a drug by ablating the stratum corneum using pulsed laser light without significantly damaging the underlying epidermis. Numerous patents teach the use of chemical enhancers for improving transdermal flux of a drug through the skin. E.g, U.S. Pat. No. 4,863,970. It would be advantageous to develop additional methods of permeating the stratum corneum or mucosa to enhance the transport of drugs into the body or analytes out of the body, particularly without the need for expensive or complicated equipment.
In view of the foregoing, it will be appreciated that providing a device and method of use thereof for introducing multiple micropores or perforations in the stratum corneum or mucosa for enhancing transport of molecules therethrough would be a significant advancement in the art.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a simple, inexpensive device for puncturing the stratum corneum or mucosa without significantly damaging the underlying tissues to facilitate transport of molecules therethrough.
It is also an object of the invention to provide a method of enhancing the passage of molecules through the stratum corneum or mucosa.
It is another object of the invention to provide a method for transdermally or transmucosally delivering a drug.
It is still another object of the invention to provide a method for transdermally or transmucosally monitoring an analyte.
These and other objects can be achieved by providing a device for reducing the barrier properties of skin or mucosa to the delivery of a substance into the body or the withdrawal of an analyte from the body comprising:
(a) a base having a lower side and an upper side;
(b) a plurality of puncturing members extending from the lower side of the base, the puncturing members configured for puncturing the skin or mucosa to a depth sufficient to reduce the barrier properties thereof without significantly damaging underlying tissues;
(c) a plurality of holes extending from the lower side of the base to the upper side of the base, the holes configured for permitting a liquid to move therethrough by capillary action; and
(d) a network of channels configured in the upper side of the base to interconnect the holes.
Preferably, the device is fabricated by microlithography and is composed of a material selected from the group consisting of silicon, metal, and plastic. It is also preferred that the puncturing member be in the shape of a pyramid or wedge. The pyramid or wedge preferably have sharp edges having corner radii of less than 1 &mgr;m. The puncturing member is preferably configured for puncturing the skin or mucosa to a depth of about 30-50 &mgr;m, and a dimension at a base thereof is preferably about 10-50 &mgr;m. The puncturing members preferably occupy up to about 50% of the surface area of the lower surface of the base.
The device preferably further comprises a mechanism for producing vibrations, the vibrations for facilitating efficient and non-traumatic penetration of the puncturing members into the skin or mucosa. A preferred vibration-producing mechanism comprises a piezo-electric transducer. It is preferred that the mechanism for producing vibrations produces vibrations in the range of about 2000 Hz to about 100 MHz.
In another illustrative embodiment of the device, an external reservoir for holding a liquid drug composition to be delivered to the body is provided. Still further, a mechanism for limiting the rate of drug delivery is preferably included in the device, the mechanism positioned between the external reservoir and the puncturing members. Such rate-limiting mechanisms can include selective permeability membranes and valve mechanisms. In another preferred embodiment, the device is disposable.
A method for reducing the barrier function of skin or mucosa to the delivery of substances into a body or withdrawal of analytes out of the body, comprises:
(a) providing a device comprising:
a base having a lower side and an upper side;
a plurality of puncturing members extending from the lower side of the base, the puncturing members configured for puncturing the skin or mucosa to a depth sufficient to reduce the barrier properties thereof without significantly damaging underlying tissues;
a plurality of holes extending from the lower side of the base to the upper side of the base, the holes configured for permitting a liquid to move therethrough by capillary action; and
a network of channels configured in the upper side of the base to interconnect the holes;
(b) contacting the device with the skin or mucosa such that the plurality of puncturing members puncture the skin or mucosa to a depth sufficient to reduce the barrier properties thereof.
A method of transdermal or transmucosal monitoring of a selected analyte in a body comprises:
(a) providing a device comprising:
a base having a lower side and an upper side;
a plurality of puncturing members extending from the lower side of the base, the puncturing members configured for puncturing said skin or mucosa to a depth sufficient to reduce the barrier properties thereof without significantly damaging underlying tissues;
a plurality of holes extending from the lower side of the base to the upper side of the base, the holes configured for permitting a liquid to move therethrough by capillary action; and
a network of channels configured in the upper side of the base to interconnect the holes, the network of channels including a reservoir;
(b) contacting the device with the skin or mucosa such that the plurality of puncturing members puncture the skin or mucosa to a depth sufficient to reduce the barrier properties thereof resulting in seepage of interstitial fluid to the surface of the skin or mucosa such that interstitial fluid moves by capillary action through the holes, through the channels, to
Bockleman Mark
Needle & Rosenberg
SpectRx, Inc.
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