CA2313458C

CA2313458C - Device for enhancing transdermal agent flux

Info

Publication number: CA2313458C
Application number: CA002313458A
Authority: CA
Inventors: Michael G. Zuck
Original assignee: Alza Corp
Current assignee: Alza Corp
Priority date: 1997-12-11
Filing date: 1998-12-09
Publication date: 2007-04-17
Anticipated expiration: 2018-12-09
Also published as: WO1999029364A1; CN1281377A; JP4061022B2; KR100572539B1; KR20010032930A; DE69806963T2; EP1035889A1; DE69806963D1; AU739616B2; EP1035889B1; AU1997599A; CN1161164C; CA2313458A1; JP2001525231A; ATE221400T1; US6050988A

Abstract

A device (2) comprising a sheet member (6) having a plurality of microprotrusions (4) extending from a bottom edge (5) for penetrating the skin of a patient. The sheet member (6) when in use being oriented in an approximately perpendicular relation to the patient's skin.

Description

t DEVICE FOR ENHANCING

..

TECHNICAL FIELD

The present invention relates to transdermal agent delivery and s sampling. More particularly, this invention relates to the transdermal delivery of agents, such as peptides and proteins, through the skin, as well as the to transdermal sampling of agents from the body, such as glucose, other body 11 analytes and substances of abuse, such as alcohol and illicit drugs.

is Interest in the percutaneous or transdermal delivery of peptides and 16 proteins to the human body continues to grow with the increasing number of t~ medically useful peptides and proteins becoming available in large quantities is and pure form. The transdermal delivery of peptides and proteins still faces t9 significant problems. In many instances, the rate of delivery or flux of 2o polypeptides through the skin is insufficient to produce a desired therapeutic 2i effect due to their large sizelhigh molecular weight and the resulting inability 22 to pass through natural pathways (pores, hair follicles, etc.) through skin. In 2~ addition, polypeptides and proteins are easily degradable during penetration 24 of the skin, prior to reaching target cells. Likewise, the passive flux of water 2s soluble small molecules such as salts is limited.
26 One method of increasing the transdermal delivery of agents relies on 2~ the application of an electric current across the body surface or on 2s "electrotransport". "Electrotransport" refers generally to the passage of a 29 beneficial agent, e.g., a drug or drug precursor, through a body surface such 3o as skin, mucous membranes, nails, and the like. The transport of the agent is 3t induced or enhanced by the application of an electrical potential, which results 32 in the application of electric current, which delivers or enhances delivery of the 3~ agent. The electrotransport of agents through a body surface may be attained ARC 2758 : ' . ' w ~ _ . , . . - - . _ y _ y in various manners. One widely used electrotransport process, 2 iontophoresis, involves the electrically induced transport of charged ions.
s Electroosmosis, another type of electrotransport process, involves the a movement of a solvent with the agent through a membrane under the s influence of an electric field. Electroporation, still another type of s electrotransport, involves the passage of an agent through pores formed by applying a high voltage electrical pulse to a membrane. In many instances, a more than one of these processes may be occurring simultaneously to s different extents. Accordingly, the term "electrotransport" is given herein its ~o broadest possible interpretation, to include the electrically induced or enhanced transport of at least one charged or uncharged agent, or mixtures ,2 thereof, regardless of the specific mechanisms) by which the agent is ~s actually being transported. Electrotransport delivery generally increases ~4 transdermal flux of agents, particularly large molecular weight species (e.g., 15 polypeptides), relative to passive or non-electrically assisted transdermal delivery. However, further increases in transdermal delivery rates and reductions in polypeptide degradation during transdermal delivery are highly ~s desirable.
One method of increasing the agent transdermal delivery rate involves zo pre-treating the skin with, or co-delivering with the beneficial agent, a skin permeation enhancer. The term "permeation enhancer" is broadly used z2 herein to describe a substance which, when applied to a body surface is through which the agent is delivered, enhances its flux therethrough. The za mechanism may involve a reduction of the electrical resistance of the body 2s surface to the passage of the agent therethrough, an increase in the zs permselectivity and/or permeability of the body surface, the creation of 27 hydrophilic pathways through the body surface, and/or a reduction in the 2a degradation of the agent (e.g., degradation by skin enzymes) during is electrotransport.
There have been many attempts to mechanically disrupt the skin ire s~ order to enhance transdermal flux, such as, U.S. Patent Nos. 3,814,097 At~ENt~D BEET

a. ;
' ~ , ~ ARC 2758 2a issued to Ganderton et al., 5,279,544 issued to Gross et al., 5,250,023 issued 2 to Lee et al., 5,611,806 issued to Jang, and 3,964,482 issued to Gerstel et al., 3 U.S. Patent No. Re.
A'~

_ " , , ., 25,637 issued to Kravitz et al. and published PCT applications WO 96/37155;
2 WO 97/48440; and WO 97/48441. These devices typically utilize tubular or 3 cylindrical structures generally, although the Gerstel U.S. Patent and the latter a two PCT publications do disclose the use of other shapes, to pierce the outer layer of the skin. The piercing elements disclosed in these references s generally extend perpendicular from a thin flat member, such as a pad or o metal sheet, which is placed on the skin surface. The flexible nature of the 8 flat member and the tubular shape of the piercing elements result in a variety s of short-comings, such as manufacturing difficulties, flexing of the flat member ,o when pressure is applied to the top of the device, uneven or poor penetration of the skin by the microblades or microtubes resulting in low transdermal ~z agent flux and, for electrotransport, increased irritation due to concentrating ~3 the drug flux through fewer pathways. The piercing elements in Jang U.S.
,a Patent 5,611,806 are points extending from the circumferencial surface of spaced disks mounted on an axle. The disks are rolled over the skin surface ,s as a pretreatment before transdermally delivering a drug.
A further shortcoming of the devices disclosed in WO 97/48440 and ,s WO 97/48441 concerns the degree of difficult in their manufacture. First, the ,s thin flexible metallic sheets/plates must be subjected to a photoetching 2o process to form openings in the sheet/plate through which the agent being transdermally delivered or sampled can pass. The photoetching is also used z2 to form the microblades. However, a second punching step is required to 23 bend the microblades to an angle roughly perpendicular to the plane of the 24 sheet. Because of the tiny size of the openings (about 0.4 x 0.5 mm) and 2s because of the large number of openings (about 50 to 300 openings/cm2), 2s accurate alignment of the micropunches with the microopenings is 2~ problematic and time consuming.

2s DESCRIPTION OF THE INVENTION
3~ The present invention provides a device suitable for increasing ~~ >~

, ~ ARC 2758 .
3a transdermal agent flux. The device has microprotrusions which consistently z and reliably penetrate a body surface (e.g., skin) to enhance agent delivery or pi~N~O 9~E~

sampling. The device of the present invention can be manufactured in high volumes and at low-cost. The device of the present invention can penetrate the stratum corneum of skin with a plurality of microprotrusions to form pathways through which a substance such as a drug can be introduced (i.e., delivery) or a substance such as a body analyte can be withdrawn (i.e., sampling). A principal advantage of the present invention is that the device ensures uniform penetration (i.e., generating the same size and depth pathways) by the microprotrusions across the width of the device. Furthermore, the present invention reproducibly provides uniformity in penetration from patient to patient.
Tn one aspect, the invention provides a device for use in introducing or withdrawing an agent through a body surface, the device having a side which in use is adapted to contact the body surface, the device comprising a sheet member having a plurality of microprotrusions for piercing the body surface, the plurality of microprotrusions being in a plane defined by the sheet member and extending from an edge of the sheet member, the sheet member being oriented in an approximately perpendicular relation to the body surface-contacting side of the device with the edge having the microprotrusions being proximal the body surface-contacting side of the device, the sheet member having a configuration which defines a void, and an agent-containing or agent receiving reservoir in the void, the reservoir being in agent transmitting communication with the body surface-contacting side of the device and means for holding the sheet member on the body surface, the means for holding being selected from anchoring barbs on the microprotrusions, angled microprotrusions, curved microprotrusions, an adhesive, a tape, a strap and/or a bandage.

4a In one aspect, the invention comprises a rigid structure which comprises a thin sheet which in use is oriented with its width perpendicular to the patient's body surface. The sheet has a plurality of microprotrusions in the same plane as the sheet and extending outward from a body proximal edge of the sheet for piercing the body surface. The thin sheet transmits force applied to a body distal edge of the sheet to the microprotrusions with substantially less dissipation of the application force in the thin sheet than prior art devices. The rigid structure formed by the thin sheet provides assured transmittance of an externally applied load to the microprotrusions without wasting energy in deflection of any portion of the device for easier, complete and reproducible skin penetration. The improved penetration of the skin by the microprotrusions because of the rigid structure formed by the thin sheet is particularly beneficial in producing increased agent flux.
The transmitted load provides nearly complete penetration by all of the microprotrusions so as to produce a substantial number of microslits in the stratum corneum for continued and reproducible transdermal agent flux. Optionally, though preferably, the rigid structure forms a void for containing an agent reservoir. The void can be filled with a reservoir material for containing the agent to be delivered or sampled.
The sheet with the plurality of microprotrusions can be manufactured more easily and less expensively than the prior art designs comprised of a 1 thin sheet having blades punched perpendicularly therefrom since the present 2 invention does not require a separate punching operation.
3 In one aspect of the invention, the device utilizes a plurality of spaced 4 sheet members which are fastened together in a roughly parallel s configuration, each of the sheet members having a plurality of 6 microprotrusions extending downward from their body proximal edges.
In another aspect of the invention, the device utilizes a sheet member s folded in a serpentine coni'iguration and having a plurality of microprotrusions 9 extending downward from the body proximal edge of the sheet member.
to In another aspect of the invention, the device utilizes a plurality of 1 i cylindrical sheet members forming concentric circles having a plurality of 12 microprotrusions extending downward from their body proximal edges, 13 respectively.
14 In yet another aspect of the invention, the device utilizes a sheet ~s member coiled in a loose spiral and having a plurality of microprotrusions 16 extending downward from the body proximal edge of the sheet member.
Optionally, though preferably, the device has a rigid support member ~s contacting the body distal edges) of the sheet members) opposite the body 19 proximal edge. The device of the present invention can be used in connection 2o with agent delivery, agent sampling or both. In particular the device of the 2l present invention is used in connection with transdermal drug delivery, 22 transdermal analyte sampling, or both. Delivery devices for use with the 23 present invention include, but are not limited to, electrotransport devices, 2a passive devices, osmotic devices and pressure driven devices. Sampling 2s devices for use with the present invention include, but are not limited to, 26 reverse electrotransport devices, passive devices, negative pressure driven, 2~ and osmotic devices.

BRIEF DESCRIPTION OF THE DRAWINGS

3 In the figures, like reference numerals refer to like elements in the 4 several drawings.
s 6 Figure 1 is a perspective view of a first embodiment of a skin ~ penetrating sheet member and a rigid support therefor;
s Figure 2 is a front elevational view of a portion of the sheet member of to Figure 1 prior to being coiled;
12 Figure 3 is a perspective view of a second embodiment of a skin 13 penetrating sheet member;

is Figure 4 is a perspective view of a third embodiment of the skin 16 penetrating sheet member;

is Figure 5 is a cross-sectional view of the rigid support and skin 19 penetrating sheet member of Figure 1 taken along line 5-5 with an agent-2o containing material within the voids between successive spirals of the sheet 21 member;

23 Figure 6 is a front elevational view of a portion of a fourth embodiment 24 of a sheet member prior to forming the sheet member into a pattern;
2s 26 Figure 7 is a bottom perspective view of the sheet member of Figure 6 2~ after being formed into a pattern;

29 Figure 8 is an alternate embodiment for microprotrusions on the sheet 3o member;

1 Figure 9 is an exploded perspective view of one embodiment of an 2 electrotransport agent delivery/sampling system according to one 3 embodiment of the present invention;

s Figure 10 is a bottom plan view of the electrotransport agent delivery/sampling system of Figure 9;
a Figure 11 is a right side elevational view of the electrotransport agent 9 delivery/sampling system of Figure 9;
to Figure 12 is a rear elevational view of the electrotransport agent 11 delivery/sampling system of Figure 9; .

13 Figure 13 is a cross-sectional view taken along line 13-13 of the 14 assembled electrotransport agent delivery/sampling system of Figure 11;
is 16 Figure 14 is a diagrammatic cross-sectional view of a passive agent 1~ delivery/sampling system in accordance with one embodiment of the present 1 a invention; and 2o Figure 15 is an exploded view of another embodiment of the skin 21 penetrating sheet member. , 2s Turning now to the drawings in detail, the skin penetrating and 26 reservoir device 2 of the present invention is generally shown in Figure 1 for 2~ use in the percutaneous administration or sampling of an agent. The terms 2s "substance", "agent" and "drug" are used interchangeably herein and broadly 29 include physiologically or pharmacologically active substances for producing a 30 localized or systemic effect or effects in mammals including humans and 31 primates, avians, valuable domestic household, sport or farm animals, or for WO 99/29364 PCfNS98/26158 ~ administering to laboratory animals such as mice, rats, guinea pigs, and the 2 like. These terms also include substances such as glucose, other body 3 analytes found in the tissue, interstitial fluid and/or blood, substances such as 4 alcohol, licit substances, illicit drugs, etc. that can be sampled through the s skin. The major barrier properties of the skin, such as resistance to agent 6 electrotransport of water soluble drugs, reside with the outer layer (i.e., ~ stratum corneum). The inner portions of the epidermis generally comprise s three layers commonly identified as stratum granulosum, stratum malpighii, 9 and stratum germinativum. There is much lower resistance to transport or to ~o absorption of an agent through the stratum granulosum, stratum malpighii, i i and stratum germinativum compared to the resistance to agent transport 12 through the stratum corneum. Thus, the microprotrusions 4 penetrate at feast i3 through the stratum corneum so that the agent is conducted with little or no i4 resistance through the skin.
~s Device 2 comprises a plurality of microprotrusions 4 extending outward i6 from edge 5 (also referred to as the body proximal edge) of a thin, sheet member or strip 6 (Figure 2). Sheet member 6 is generally compliant and ~a flexible because of its relatively thin thickness, for example, about 5 p,m to about 100 pm, preferably about 25 um to about 50 Vim. Coiling (Figure 1), 2o folding (Figures 4 and 7), curving (Figure 3), stacking {Figure 15), as well as 2 ~ other forms of forming the sheet member 6 from its generally planer state 22 along its entire length, form a rigid structure having a plurality of voids 27, 127 23 for holding a reservoir that contains the agent that is to be delivered or that is 24 adapted to receive the agent that is to be sampled. Those skilled in the art 2s will appreciate that spacers can be placed within voids 27, optionally secured 26 together with fasteners such as fastening bolts or pins, to keep the spacing 2~ between adjacent turns (Figure 1 ) or folds (Figure 4) of sheet member 6 2s constant. To prevent deformation or flexing side to side of sheet member 6 as 29 the microprotrusion array is applied to the body surface, support member 15 3o is preferably placed across the skin distal edge 7 (also referred to as the top 3 i edge) of sheet member 6 (Figures 1 and 5).

Optional support member 15 can be a variety of configurations, for 2 example but not limited to the embodiments shown in Figures 1 and 5. The 3 support member 15 transmits force that is applied to the top of the support 4 member across the skin distal edge 7 of sheet member 6 so that each of the s microprotrusions 4 receive substantially the same amount of force for 6 penetrating the skin. Force applied to the edge 7, and directed toward the skin, causes the microprotrusions 4 to pierce at least through the stratum s corneum.
9 Various embodiments of the device 2 are illustrated in the figures io although other configurations beyond those specifically illustrated are within i ~ the scope of the invention. In each of these embodiments, the device 2 is i2 comprised of sheet member 6, or a plurality of sheet members 6, 106 (see t3 Figures 3 and 15) having their width oriented generally perpendicular to a t4 body surface (e.g., skin), thereby forming vertical walls, to efficiently (i.e., is without bending or flexing the sheet member 6) transmit a force applied t6 across the skin distal edge 7 of the sheet member 6 to the microprotrusions 4.
i~ The width (i.e., the distance from the skin distal edge to the skin proximal ~s edge) of the sheet member 6 is optionally, though preferably, sufficient to create a plurality of voids 2? for the agent reservoir. The number and the 2o volume of voids 27 depends on a variety of factors, for example, the relative 2~ structural integrity or flexibility of the sheet member 6, the distance across the z2 device 2, the size of the agent reservoir skin-contact area, and the reservoir 23 volume required for the therapy (in the case of drug delivery from the 24 reservoir).
2s A particularly preferred configuration for the device is illustrated in 26 Figure 15 and comprises a plurality of individual sheet members 106 stacked 2~ together to form device 2'. Each of the sheet members 106 has a pair of 2s holes 102, 103, through which bolts 105 are inserted. Spacers (e.g., tubes) z9 107 are positioned between each adjacent pair of sheet members 106 to form 30 voids 127 therebetween. The spaced sheet members 106 are held together 31 as a unit by securing nuts 104 on the ends of bolts 105, or using other known fasteners. As in the Figure 1 device, the voids 127 can be filled with a 2 reservoir matrix material {e.g., a gel) adapted to contain the beneficial agent s to be delivered or to receive the body analyte to be sampled. Those skilled in a the art will appreciate that spacers having other than tube-like configurations s (e.g., square or rectangular blocks) can also be used to provide voids 127 6 between adjacent sheet members 106 as long as the spacers do not form a complete barrier between the agent reservoir 8 (i.e., the agent reservoir s contained in the voids 127) and the skin: Furthermore, more than two sets of 9 bolts 105, or other fastening pins, may be used to secure the sheet members io 106 and spacers 105 together.
I 1 The microprotrusions 4 can be microblades or any of a variety of ~2 configurations for piercing the skin or body surface. The microprotrusions 13 penetrate the stratum corneum of the epidermis when pressure is applied to Z4 the top (body distal side) of the support member 15 to increase the ~s administration of, or sampling of, an agent through a body surface. The term i6 "body surface" as used herein refers generally to the skin, mucous membranes, and nails of an animal or human, and to the outer surface of a t8 plant. The microprotrusions 4 penetrate the body surface to create good ~9 agent conduction from the system into the body, or vice versa. In some 2o configurations, spaces 9 (see Figure 2) are formed between each of the 2 i microprotrusions 4 to create a lower blade density and/or to provide "stops"
22 which prevent the device from penetrating the body surface beyond the length 23 of the microprotrusions 4. The agent can be administered or sampled at a 24 controlled rate of release from or collection in the voids 27 housing the agent-2s containing or agent-receiving reservoir through an agent rate controlling 26 material such as a flux control membrane {not shown) positioned between the 2~ voids 27, 127 and the body surface.
2a The microprotrusions or microblades 4 are generally formed from a 29 single piece of material (as shown in Figure 2) and are sufficiently sharp and 30 long for penetrating at least the stratum corneum of the skin. In one 3 i embodiment, the microprotrusions 4 and the sheet member 6 are essentially i impermeable or are impermeable to the passage of an agent. The width of 2 each microprotrusion 4 can be any of a range of widths. The width of the 3 microprotrusion 4 at the intersection of the microprotrusion and the body 4 surface after the microprotrusion array has been inserted is typically at least s about 25 p.m. The required length of the blades is subject to variation of the body surface being penetrated and corresponds to at least the natural thickness of the stratum corneum, for one of the principal features of the invention is that the microprotrusions are to penetrate at least through the 9 stratum corneum and into the epidermis. Usually, the rnicroprotrusions 4 will to have a length and configuration which achieves a depth of penetration of > > about 25 ~m to about 400 Vim, with the depth of penetration for most i2 applications being between about 50 ~.m to about 200 Vim. The i3 microprotrusions 4 can have slanted (i.e., angled) leading edges to further ~4 reduce the insertion force required to press the microprotrusions into the skin is tissue. The leading edges of each microprotrusion 4 can all be the same i6 angle or can be at different angles suitable for penetrating the skin.
~ Alternatively, the leading edge of each microprotrusion 4 can be curved is having, for example, a convex or concave shape or be divided into any i9 number of angled segments such as the first segment being relatively steep 2o ith respect to vertical and the second segment being more gradually angled 2 ~ with respect to vertical.
22 The sheet member 6 of the present invention can optionally include 23 microprotrusion anchoring means for improving the attachment of the device 24 to the skin so that a continuous agent conducting pathway through the body 2s surface is preserved even during movement of the patient and/or the patient's 26 body surface. Some or all of the microprotrusions 4 can have a barb which 2~ assists in anchoring the sheet member 6 and any corresponding device or 2s structure used in combination therewith to the skin. Microblade anchoring 29 barbs are described in more detail in WO 97/48440, and Reed et al. U.S.
3o Patents 5,312,456 and 5,569,272 of which any of the disclosed configurations 3 t can be used with the present invention. The barbs are but one example of WO 99/29364 PCT/US9$/26158 i microprotrusion anchoring means. In addition to anchoring means on the 2 blades, other means for holding the device in contact with the skin can be 3 used, such as but not limited to adhesive agent-containing reservoirs in the 4 voids 27, 127, peripheral adhesive, tape, a strap, or an elastic bandage.
s The microprotrusion configurations of Figures 6, 7 and 8 facilitate 6 penetration of the body surface but also assist in anchoring the device to the ~ body surface. Sheet member 6 in Figure 6 has angled or slanted s microprotrusions 4. In sections 72 and 76 of sheet member 6, the 9 microprotrusions 4 are slanted to the right along the length of the sheet ~o member 6. In section 74, the microprotrusions are slanted to the left along ~ i the length of the sheet member 6. As a result, when sheet member 6 is i2 folded along lines 78 into the serpentine pattern shown in Figure 7, all of the 3 microprotrusions 4 are slanted in the same direction. With this configuration, i4 the sheet member 6 and elements attached thereto can be slid along the body is surface in the direction of the slanted microprotrusions while pressing down i6 on the device to facilitate better penetration against the viscoelastic nature of t~ the body surface. This configuration also aids in anchoring the device to the ~ a body surface because the top edges 80 of each of the microprotrusions act 19 similar to the barbs described previously.
2o Similarly, sheet member 6 in Figure 8 has curved, sweeping 2 i microprotrusions 4. The microprotrusions 4 sweep to the left along the length 22 of the sheet member 6. As a result, when sheet member 6 is formed into a 2s curved configuration, such as for example those of either Figures 1 or 3, sheet 2a member 6 and elements attached thereto can be turned clockwise in the 2s direction of the sweeping microprotrusions while pressing down on the device 26 to facilitate better penetration against the viscoelastic nature of the body 2~ surface. This configuration also aids in anchoring the device to the body 2a surface because the top edges 80 on each of the microprotrusions act similar 29 to the barbs described previously.
3o The pattern for the microprotrusion array members 6 can be produced 3 i with a photolithography process followed by a chemical etching process. A

t thin sheet member 6 of metal such as stainless steel or titanium is patterned 2 photo-lithographically with patterns containing blade-like structures. In general, a thin laminate dry resist or wet resist is applied on the sheet a member 6 which typically has a thickness of about 7 p.m to about 100 p,m, s preferably about 25 pm to about 50 pm. The resist is contact exposed using a mask having the desired pattern and is subsequently developed. These operations are conducted in much the same way that they are for the s manufacture of a printed circuit board. The sheet member 6 is then etched 9 using acidic solutions. After the pattern has been etched, the sheet member to is rolled or folded into the desired configuration (i.e., spiral, serpentine, t t concentric circles, etc.) having voids 27 for holding the agent-containing t2 reservoir. The finished structure provides microprotrusions 4 at the skin t3 proximal edge 5 of sheet member 6. The adjacent turns of member 6 (see t4 Figures 1 and 5) form adjacent vertical walls between which are voids 27 is containing a reservoir 8 (e.g., a gel reservoir; see Figure 5) for containing an t6 agent (e.g., a drug) therein or for the passage of an agent therethrough when t~ the sheet member 6 is applied to the body surface.
t8 In one embodiment of the etching process, a dry resist (e.g., t9 "DYNACHEM FL" (available from Dynachem located in Tustin, CA) is applied 20 12.5 ~.m thick to one or both sides of the sheet member 6 and exposed in a 2t standard manner. Then using a suitable spray etcher (e.g., "DYNAMIL VRP
22 10/NM" available from Western Tech. Assoc. located in Anaheim, CA) a 23 mixture of ferric chloride, water and hydrochloric acid is sprayed onto the 24 resist and sheet member 6 at about 52° C for two minutes. A standard 2s caustic stripper is used for the resist removal.
26 In another embodiment of the etching process, a wet resist (e.g., 2~ "SHIPLEY 111S" available from Shipley Corporation, located in Marlborough, 2s MA) is applied 7.5 ~m thick at about 21 ° C to one or both sides of the sheet 29 member 6 and exposed in a standard manner. Then a suitable etchant (e.g., 3o ferric chloride) is sprayed onto the resist and sheet member at about 49° C. A
3 t standard caustic stripper is used for the resist removal.

The sheet member 6 and microprotrusions 4 are made from materials 2 that have sufficient strength and manufacturability to produce 3 rnicroprotrusions, such as, glasses, ceramics, rigid polymers, reinforced (e.g., 4 carbon fiber reinforced) polymers, metals and metal alloys. Examples of s metals and metal alloys include but are not limited to stainless steel, iron, steel, tin, zinc, copper, gold, platinum, aluminum, germanium, zirconium, titanium and titanium alloys. Each of the sheet member and microprotrusions s can have a thin layer of gold, platinum, iridium, titanium, or rhodium plating.
Examples of glasses include silicas and devitrified glasses such as ~o "PHOTOCERAM" available from Corning in Corning, NY. Examples of 1 ~ polymers include but are not limited to polystyrene, polymethylmethacrylate, i2 polypropylene, polyethylene, "BAKELITE", cellulose acetate, ethylcellulose, >; styrene/acrylonitrile copolymers, stryrene/butadiene copolymers, i4 acrylonitrile/butadiene/styrene (ABS) copolymers, polyvinyl chloride and is acrylic acid polymers including polyacrylates and polymethacrylates.
16 The number of microprotrusions 4 and reservoirs 8 of any of the embodiments of the sheet member 6 is variable with respect to the desired is flux rate, agent being sampled or delivered, delivery or sampling device used i9 (i.e., electrotransport, passive, osmotic, pressure driven, etc.), and other 2o factors as will be evident to one of ordinary skill in the art. In general, the 2i larger the number of microprotrusions per unit area (i.e., microblade density), 22 the less concentrated the flux of the agent in the skin because there are a 23 greater number. of pathways through the skin. Consequently with 24 elecrotransport delivery or sampling, a smaller number of microprotrusions 2s per unit area, leads to the transport of the agent through the skin becoming 26 more concentrated in fewer pathways. Higher concentrations of agents in a 2~ skin pathway can lead to higher incidences and/or severity of skin reactions 2s (e.g., irritation). Therefore, larger microblade densities are generally preferred 29 to reduce the incidence and/or severity of skin reactions.
3o The present invention can also be used for sampling a body anaiyte ~ (e.g., glucose) transdermally. The analyte to be sampled is extracted through I the openings cut in the stratum corneum by the microprotrusions 4 and 2 collected in the sampling reservoir 8 (Figure 5). Known analyte (e.g., glucose) 3 sensing elements can be placed directly in reservoir 8. Alternatively, the 4 reservoir 8 can be removed from the device and suitably processed in order to s determine the amount of analyte collected. Such devices are useful in 6 monitoring the patient's blood glucose concentration (i.e., through appropriate software which correlates~the amount of glucose extracted with the s concentration of glucose in the blood) and can further be used to adjust a treatment regime which typically includes administration of insulin to the to patient and/or appropriate modification of diet and/or exercise.
1 t One embodiment of the present invention relies on the application of t2 an electric current across the body surface or "electrotransport". It will be t3 appreciated by those working in the field that the present invention can be t4 used in conjunction with a wide variety of electrotransport systems, as the is invention is not limited in any way in this regard. For examples of t6 electrotransport systems, reference may be had to U.S. Patent Nos.
5,147,296 to Theeuwes et al., 5,080,646 to Theeuwes et al., 5,169,382 to to Theeuwes et al., 5,423,739 to Phipps et al., 5,385,543 to Haak et al., t9 5,310,404 to Gyory et al., and 5,169,383 to Gyory et al., of which any of the 2o disclosed electrotransport systems can be used with the present invention.
2 t Device 2 and support member 15 when used in an electrotransport 22 system are preferably electrically insulated from an electrode or other electric 23 current conducting members in order to avoid short circuiting the agent-24 containing, or agent-receiving, reservoir contained in the voids 27, 127.
This 2s can be accomplished by using electrically insulative materials or coatings for 26 sheet member 6, 106 and/or support member 15.
Figures 9-13 illustrate a representative electrotransport 2s delivery/sampling device 10 that may be used in conjunction with the present 29 invention. Device 10 comprises an upper housing 16, a circuit board 3o assembly 18, a lower housing 20, donor electrode 22, counter electrode 24, 3 t donor reservoir in voids 27, counter reservoir 28 and skin-compatible i adhesive 30. Upper housing 16 has lateral wings 31 which assist in holding 2 device 10 on a patient's skin. Printed circuit board assembly 18 comprises an 3 integrated circuit 19 coupled to discrete components 40 and battery 32.
4 Circuit board assembly 18 is attached to housing 16 by posts (not shown in s the Figures) extending from the lower (skin proximal) surface of housing 16 6 and passing through openings 13a and 13b, the ends of the posts being heated/melted in order to heat stake the circuit board assembly 18 to the s housing 16. Lower housing 20 is attached to the upper housing 16 by means 9 of adhesive layer 30, the upper surtace 34 of adhesive layer 30 being adhered io to both lower housing 20 and upper housing 16 including the bottom surfaces > > of wings 31. Shown (partially) on the underside of circuit board assembly t2 is a button cell battery 32. Other types of batteries may also be employed to ~3 power device 10 depending on the need.
~4 The device 10 is generally comprised of battery 32, electronic circuitry is 19,40, electrodes 22,24, counter reservoir 28, and device 2 with sheet 6 member 6 and donor reservoir 8 therein, all of which are integrated into a self-~ contained unit. Electrodes 22, 24, donor reservoir 8 and counter reservoir to are retained by lower housing 20. The outputs (not shown in Figure 18) of the 9 circuit board assembly 18 make electrical contact with the electrodes 24 and 20 22 through openings 23,23' in the depressions 25,25' formed in lower housing 21 20, by means of electrically conductive adhesive strips 42,42'. Electrodes 22 and 24, in turn, are in direct mechanical and electrical contact with the top 23 sides 44',44 of the donor reservoir 8 and counter reservoir 28. The bottom 24 side 46 of reservoir 28 contacts the patient's skin through the opening 29 in 2s adhesive layer 30. The bottom side 46' of the donor reservoir 8 contacts the 26 patient's skin through opening 29'. The agent (e.g., drug) in the donor 2~ reservoir 8 is typically in the form of a solution, most preferably an aqueous 2s solution, which solution is contained in a solid matrix material such as a 29 sponge, a hydrophilic polymer matrix (e.g., a hydrogel) which allows free 3o mobility of the agent therethrough. The reservoir matrix material fills the voids 127 between adjacent sheet members 106 (as is more clearly shown in 2 Figure 15) such that the agent reservoir 8 is in contact with the body surface.
3 The device 10 adheres to the patient's body surface (e.g., skin) by 4 means of a peripheral adhesive layer 30 (which has upper adhesive side 34 s and body-contacting adhesive side 36) and, optionally, anchoring elements on the device 2 of any of the embodiments discussed herein. The adhesive side ~ 36 covers the entire underneath side of the device 10 except where the s device 2 and the counter electrode reservoirs are located. The adhesive side 9 36 has adhesive properties which assures that the device 10 remains in place io on the body during normal user activity, and yet permits reasonable removal i i after the predetermined (e.g., 24-hour) wear period. Upper adhesive side 12 adheres to lower housing 20 and retains the electrodes and agent reservoirs 13 within housing depression 25, 25' as well as retains device 2 to lower housing is 20 and lower housing 20 to upper housing 16.
is In one embodiment of the agent delivery/sampling device there is a 16 release liner (not shown) on the device 10 for maintaining the integrity of ~ adhesive layer 30 when the device is not in use. In use, the release liner is i8 stripped from the device before the device is applied to the skin. Device t9 also has a push button switch 12, which when pressed turns the device 10 on 2o which is made apparent to the user by means of LED 14 becoming lit. Agent 2~ is delivered through the patient's skin (e.g., on the arm) by electrotransport 22 over the predetermined delivery interval.
23 In other embodiments of the present invention, passive transdermal 24 delivery or sampling devices are used with the device 2. It will be appreciated 2s by those working in the field that the present invention can be used in 26 conjunction with a wide variety of passive transdermal systems, as the 2~ invention is not limited in this regard. For examples of passive systems, 2s reference may be had to, but not limited to, U.S. Patent Nos. 4,379,454 to 29 Campbell et al., 4,588,580 to Gale et al., 4,832,953 to Campbell et al., so 4,698,062 to Gale et al., 4,867,982 to Campbell et al., and 5,268,209 to Hunt 3 i et al., of which any of the disclosed systems can be used with the present i invention. One example of a passive transdermal delivery/sampling device is 2 illustrated in Figure 14. Optional support member 15 having the body distal 3 edge of sheet member 6 embedded therein is housed in an outer housing 53 4 and a foam pad or band 57 which can be applied to the body surface. The s edges of sheet member 6 need not be embedded in the support member 15.
6 Support member 15 is sufficiently rigid so as not to deform when force is applied thereto and so as to more evenly transmit the applied force to the top 8 edge of the sheet member 6 across the width and length of device 2.
9 Preferably, although not required, the passive delivery/sampling device has a to peripheral adhesive on the body-contacting surface of foam pad 57.
i ~ It will be appreciated by those working in the field that the present t2 invention can also be used in conjunction with a wide variety of osmotic and ~3 pressure driven agent delivery or agent sampling systems, as the invention is t4 not limited to a particular device in this regard. For examples of osmotic and ~s pressure driven devices, reference may be had to U.S. Patent Nos. 4,340,480 to Eckenhoff, 4,655,766 to Theeuwes et al., 4,753,651 to Eckenhoff, i~ 5,279,544 to Gross et al., 4,655,766 to Theeuwes, 5,242,406 to Gross et al., is and 4,753,651 to Eckenhoff any of which can be used with the present 19 invention.
2o This invention has utility in connection with the delivery of agents within 2~ any of the broad class of drugs normally delivered through body surfaces and 22 membranes, including skin. In general, this includes drugs in ail of the major 2~ therapeutic areas. The invention is also useful in the transdermal delivery of 24 proteins, peptides and fragments thereof, whether naturally occurring, 2s chemically synthesized or recombinantly produced. The invention may 26 additionally be used in conjunction with the delivery of vaccines, nucleotidic 2~ drugs, including oligonucleotide drugs, polynucleotide drugs, and genes.
2s These substances typically have a molecular weight of at least about 300 29 daltons, and more typically have a molecular weight of at least about 300 to 30 40,000 daltons. As mentioned, the device 2 of the present invention can also 3~ be used with sampling devices including, but not limited to, reverse 1 electrotransport (i.e., reverse iontophoresis and/or reverse electroosmosis in 2 the case of sampling uncharged materials such as glucose), osmosis, and 3 passive diffusion. For example, reference may be had to U.S. Patent Nos.
4 4,756,314 to Eckenhoff et al., 5,438,984 to Schoendorter, 5,279,543 to s Glikfeld et al., and 5,362,307 to Guy et al.
It will be appreciated by those of ordinary skill in the art that the ~ invention can be embodied in other specific forms without departing from the s spirit or essential character thereof. The presently disclosed embodiments 9 are therefore considered in all respects to be illustrative and not restrictive.
~o The scope of the invention is indicated by the appended claims rather than i t the foregoing description, and all changes which come within the meaning i2 and range of equivalents thereof are intended to be embraced therein.

Claims

CLAIMS:

1. A device for use in introducing or withdrawing an agent through a body surface, the device having a side which in use is adapted to contact the body surface, the device comprising a sheet member having a plurality of microprotrusions for piercing the body surface, the plurality of microprotrusions being in a plane defined by the sheet member and extending from an edge of the sheet member, the sheet member being oriented in an approximately perpendicular relation to the body surface-contacting side of the device with the edge having the microprotrusions being proximal the body surface-contacting side of the device, the sheet member having a configuration which defines a void, and an agent-containing or agent-receiving reservoir in the void, the reservoir being in agent transmitting communication with the body surface-contacting side of the device and means for holding the sheet member on the body surface, the means for holding being selected from anchoring barbs on the microprotrusions, angled microprotrusions, curved microprotrusions, an adhesive, a tape, a strap and/or a bandage.

2. The device of Claim 1, wherein a plurality of said sheet members are fastened together.

3. The device of Claim 2, wherein said sheet members are fastened together in spaced and roughly parallel orientation.

4. The device of Claim 1, wherein the sheet member has a spiral configuration and the void is defined by adjacent spirals.

5. The device of Claim 1, wherein the sheet member has a serpentine configuration and the void is defined by adjacent folds.

6. The device of Claim 1, wherein the sheet member comprises a plurality of concentric circular sheets and the void is defined by adjacent concentric circular sheets.

7. The device of Claim 1, wherein the reservoir is an agent-containing reservoir.

8. The device of Claim 7, wherein the agent is a therapeutic agent.

9. The device of Claim 8, wherein the agent is a therapeutic drug.

10. The device of Claim 7, further comprising a therapeutic agent delivery device.

11. The device of Claim 10, wherein the delivery device comprises a transdermal drug delivery device.

12. The device of Claim 1, wherein the reservoir is an agent-receiving reservoir.

13. The device of Claim 12, wherein the agent is a body analyte.

14. The device of Claim 13, wherein the body analyte is glucose.

15. The device of Claim 12, further comprising an agent sampling device.

16. The device of Claim 15, wherein the sampling device samples glucose and measures or estimates concentration of glucose in the body.

17. The device of Claim 1, further comprising a rigid structural support extending across at least a portion of the sheet member configuration.

18. The device of Claim 17, wherein the rigid structural support contacts a second edge of the sheet member which second edge is opposite the edge having the microprotrusions.