The present invention relates to a multiple part electrotransport drug delivery system for driving ionic drug across a body surface or membrane. In particular, the invention relates to a system having an electronic part and a drug reservoir part that can be coupled together before drug delivery.
The delivery of active pharmaceutical agents through the skin provides many advantages, including comfort, convenience, and non-invasiveness. Gastrointestinal irritation and the variable rates of absorption and metabolism including first pass effect encountered in oral delivery are avoided. Transdermal delivery also provides a high degree of control over blood concentrations of any particular active agent.
The natural barrier function of the body surface, such as skin, presents a challenge to delivery therapeutics into circulation. Devices have been invented to provide transdermal delivery of drugs. Transdermal drug delivery can generally be considered to belong to one of two groups: transport by a “passive” mechanism or by an “active” transport mechanism. In the former, such as fentanyl transdermal systems available from Jassen Pharmaceuticals and other drug delivery skin patches, the drug is incorporated in a solid matrix, a reservoir with rate-controlling membrane, and/or an adhesive system.
Passive transdermal drug delivery offers many advantages, such as ease of use, little or no pain at use, disposability, good control of drug delivery and avoidance of hepatic first-pass metabolism. However, many active agents are not suitable for passive transdermal delivery because of their size, ionic charge characteristics, and hydrophilicity. Most passive transdermal delivery systems are not capable of delivering drugs under a specific profile, such as by ‘on-off’ mode, pulsatile mode, etc. Consequently, a number of alternatives have been proposed where the flux of the drug(s) is driven by various forms of energy. Some examples include the use of iontophoresis, ultrasound, electroporation, heat and microneedles. These are considered to be “active” delivery systems.
One method for transdermal delivery of such active agents involves the use of electrical current to actively transport the active agent into the body through intact skin by electrotransport. Electrotransport techniques may include iontophoresis, electroosmosis, and electroporation. Electrotransport devices, such as iontophoretic devices are known in the art, see, e.g., U.S. Pat. Nos. 5,057,072, 5,084,008, 5,147,297, 6,039,977, 6,049,733, 6,171,294, 6,181,963, 6,216,033, and US Patent Publication 20030191946. One electrode, called the active or donor electrode, is the electrode from which the active agent is delivered into the body. The other electrode, called the counter or return electrode, serves to close the electrical circuit through the body. In conjunction with the patient's body tissue, e.g., skin, the circuit is completed by connection of the electrodes to a source of electrical energy, and usually to circuitry capable of controlling the current passing through the device. If the substance to be driven into the body is ionic and is positively charged, then the positive electrode (the anode) will be the active electrode and the negative electrode (the cathode) will serve as the counter electrode. If the ionic substance to be delivered is negatively charged, then the cathodic electrode will be the active electrode and the anodic electrode will be the counter electrode.
A prior iontophoretic system similar to that of U.S. Pat. No. 6,181,963 is shown in
Printed circuit board assembly 18 includes an integrated circuit 19 coupled to discrete electrical components 40 and battery 32. Printed circuit board assembly 18 is attached to housing 16 by posts (not shown) passing through openings 13a and 13b, the ends of the posts being heated/melted in order to heat weld the circuit board assembly 18 to the housing 16. Lower housing 20 is attached to the upper housing 16 by means of adhesive 30, the upper surface 34 of adhesive 30 being adhered to both lower housing 20 and upper housing 16 including the bottom surfaces of wings 15.
Shown (partially) on the underside of printed circuit board assembly 18 is a battery 32, preferably a button cell battery and most preferably a lithium cell. Other types of batteries may also be employed to power device 10.
The circuit outputs (not shown in
Recently, there have been suggestions to provide different parts of an electrotransport system separately and connect them together for use. For example, such connected-together systems might provide advantages for reusable controller circuit. In reusable systems, the drug-containing units are disconnected from the controller when the drug becomes depleted and a fresh drug-containing unit is then connected to the controller again. Examples of electrotransport devices having parts being connected together before use include those described in U.S. Pat. No. 5,320,597 (Sage, Jr. et al); U.S. Pat. No. 4,731,926 (Sibalis), U.S. Pat. No. 5,358,483 (Sibalis), U.S. Pat. No. 5,135,479 (Sibalis et al.), UK Patent Publication GB2239803 (Devane et al), U.S. Pat. No. 5,919,155 (Lattin et al.), U.S. Pat. No. 5,445,609 (Lattin et al.), U.S. Pat. No. 5,603,693 (Frenkel et al.), and WO1996036394 (Lattin et al.).
However, many of the prior connected-together systems are cumbersome to use and do not provide for easy assembly and use.
What is needed is an electrotransport device in which the electronic part and the reservoir part can be easily assembled about the time of use.
The present invention relates to an electrotransport device for delivering a therapeutic agent through a body surface of a patient. The device has an electronic module that can be coupled with an agent module (e.g., reservoir module) before use to provide circuitry for driving the drug, thereby forming the assembled electrotransport device. The present invention provides such electrotransport devices and methods of making and using such electrotransport devices.
In one aspect, the agent module has a compartment (e.g., reservoir) containing the therapeutic agent for delivery through the body surface by electrotransport. The agent module also has a cutout forming a channel having a narrow channel portion and a less narrow channel portion. The channel has channel walls. The electronic module has circuitry for electrically driving the therapeutic agent for electrotransport and has a body with a narrow portion and a less narrow portion corresponding to the narrow portion and the less narrow portion of the channel. The narrow portion of the electronic module can be guided into the narrow channel portion through the less narrow channel portion of the agent module.
Because of the shapes of the electronic module and the agent module of the present invention, the two modules can easily be aligned to fit together in correct orientation and therefore correct electrical polarity. Further, due to the presence of wide (or less narrow) and narrow portions of the channel in the agent module, the electronic module can be guided into position to fit with the agent module. Also, because of the corresponding shapes of the electronic module and the agent module, the two modules can be match fitted together to result in tight seams (junctions) to provide protection against liquid and other unintended intrusion of unwanted material.
In an aspect, the present invention provides a method of making an electrotransport device for delivering a therapeutic agent through a body surface of a patient. The method includes coupling an agent module to an electronic module, wherein the agent module has a cutout forming a channel having a narrow channel portion and a less narrow channel portion with channel walls. The electronic module has circuitry for electrically driving the therapeutic agent for electrotransport. The electronic module further has a body with a narrow portion and a less narrow portion corresponding to the narrow portion and the less narrow portion of the channel. The method includes guiding the narrow portion of the electronic module into the narrow channel portion through the less narrow channel portion of the agent module to couple the modules together.
In another aspect, an electrotransport device is provided in which the device has an agent module that can be coupled with an electronic module, which is multilayered. In one aspect, the electronic module has an upper cover and a lower cover sandwiching or surrounding about and protecting a printed circuit board, which contains circuitry for electrically driving the therapeutic agent for electrotransport. The agent module has a compartment (e.g., reservoir) containing the therapeutic agent for delivery through the body surface by electrotransport. In one aspect, the agent module has a cutout forming a channel having a narrow channel portion and a less narrow channel portion with channel walls; and the electronic module has a body with a narrow portion and a less narrow portion corresponding to the narrow portion and the less narrow portion of the channel. The narrow portion of the electronic module can be guided into the narrow channel portion through the less narrow channel portion of the agent module. Having multiple layers, the electronic module can provide a resilient top layer for tight seal with the agent module and yet provide stiff structures to protect the printed circuit board and to firmly couple with corresponding stiff structures in the agent module. Thus, the present invention provides advantageous devices that are sturdy and yet well protected against liquid penetration at externally visible seams (where the electronic module and the agent module surfaces meet). The multilayered construction of the electronic module, and preferably of the agent module in certain embodiments allows for appropriate placement of the fitting portions. Because the layers can be made separately and then affixed together, either by mechanical anchoring, chemical bonding or by molding together by heat, the parts that need to be fitted together can be positioned at strategic locations for optimal cooperative operation. The layered construction of the electronic module and the agent module provides advantages in making and positioning of the couplers. The layered construction further provides protection of the electronics from mechanical disturbance and moisture as well as protection of the reservoir(s) from mechanical disturbance.
The present invention also provides methods of making and methods of using the above electrotransport devices. After the electronic module has been coupled to the agent module, the device is applied onto the body surface of a patient.
It is to be understood that the present invention of engaging two modules can be applied to electrotransport devices such as iontophoretic devices, electroosmosis devices, and electroporation devices, as long as there are two modules that need to be coupled together for mechanical and electrical engagement.
The present invention is illustrated by way of examples in embodiments and not limitation in the figures of the accompanying drawings in which like references indicate similar elements. The figures are not shown to scale unless indicated otherwise in the content.
The present invention is directed to an electrotransport drug delivery system that has two parts which are assembled together before drug administration to a patient. In particular, the system includes an agent-containing module (“agent module” for short) having a compartment (e.g., reservoir) containing the drug (or therapeutic agent) and an electronic module for coupling to the agent module to drive the drug in electrotransport through a body surface.
The practice of the present invention will employ, unless otherwise indicated, conventional methods used by those skilled in the art of mechanical and electrical connections in drug device development.
In describing the present invention, the following terminology will be used in accordance with the definitions set out below.
The singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a polymer” includes a single polymer as well as a mixture of two or more different polymers.
The present invention provides an electrotransport device that is assembled before use for electrotransport delivery of ionic compounds (e.g., ionic drugs such as fentanyl and analogs, polypeptides, and the like) through a surface, such as skin.
Electrotransport devices, such as iontophoretic devices are known in the art, e.g., U.S. Pat. No. 6,216,033. The structures, drugs, and electrical features of U.S. Pat. No. 6,216,033 and in
The PCB assembly 206 is sandwiched between an upper cover (or top cover) 218 and a lower cover (or bottom cover) 220 so that the PCB assembly 206 is enclosed and protected by them except for electrical connectors (not shown in
The upper cover 218 of the electronic module 204 includes a lower layer 226 made of rigid or semirigid material (e.g., polypropylene) and an upper layer 228 made of a less rigid elastomer, such as ethylene vinyl acetate or ethylene-octene copolymer, e.g., ethylene-octene copolymers available under the tradename ENGAGEL® from Dow Chemical Company. The polymeric material from which the upper layer 228 is made is softer and more resilient than the polymeric material of the lower layer 226 so that when the electronic module is coupled to match with the reservoir module 202 the upper layer 228 can match contours snuggly with the reservoir module to provide a splash-water resistant or liquid resistant (drip-proof) seam, as well as provide visual confirmation of correct assembly. In other words, liquid will not penetrate to cause failure of the device through the liquid resistant seam during occasional momentary water exposure such as splashing as under a short spray. Further, by using materials that are hydrophobic and/or that can butt tightly, the seam can be made to keep out aqueous liquid such as water in normal daily routine use. For example, the material at the seam can have a coating of a hydrophobic material such as polytetrafluoroethylene. A button cover portion 230 of the upper layer 228 is adequately flexible and soft such that finger pressure by a finger pressing on the button cover portion 230 can activate or deactivate the switch 214. It is noted that other elastomers or semi-rigid polymers can also be used so long as it provides an adequate amount of resiliency.
A cutout 232 on the upper layer 228 at the anterior end 233 of the device 200 allows light transmitted from the display 216 to be visible from the top view. Of course, in alternative designs, the display itself can also include LED, digital display, etc. for displaying information. For example, the embodiment in
In this embodiment, the lower layer 226 of the upper cover 218 of the electronic module 204 is made of a transparent or translucent polymeric material that is stiffer than the upper layer 228 to protect the PCB assembly 206. A window portion 234 fits into the cutout 232 in the upper layer 228 and allows light emitted from the display 216 to be seen through the transparent or translucent window portion 234 from a top view. A cutout (opening) 236 on the lower layer 226 above the display 216 allows the display 216 to be viewed through the transparent or translucent window portion 234. The cutout 236 can alternatively be covered by a transparent or translucent material for the display 216 to be seen. Useful transparent or translucent polymeric material for the window 234 includes acrylic, polycarbonate, polyethylene, polypropylene, polyethylene terephthalate, and the like. Further, glass fibers, glass particles, silica, and the like can also be included in the transparent or translucent polymeric material to provide more stiffness, to provide support and protection of the PCB assembly 206 and to secure to the lower cover 220 of the electronic module 204. Additives to enhance the bonding in the polymeric materials and dispersion aids to improve dispersion of additives or light in the transparent or translucent material can also be used in the molding material. For a digital display, a window with sufficient transparency for the digits to be read is provided.
The upper layer 228 has a wide portion 238A gradually narrowing from the wide portion 238A through a narrowing portion 240A to a narrow portion 242A. The lower layer 226 also has a wide portion 238B gradually narrowing from the wide portion 238B through a narrowing portion 240B to a narrow portion 242B. The wide portion 238A, narrowing portion 240A, and narrow portion 242A of the upper layer 228 are generally the same size or slightly wider in the lateral direction than the wide portion 238B, narrowing portion 240B, and narrow portion 242B of the lower layer 226 such that the wide portion 238A, narrowing portion 240A, and narrow portion 242A of the upper layer 228 can extend to match contours with the wide portion 238C, narrowing portion 240C, and narrow portion 242C of the outer upper portion 252 of the reservoir module 202, resulting in a puzzle-piece fit. A puzzle-piece fit means a matching fit between two pieces as appears in a jig-saw puzzle.
The lower cover 220 of the electronic module 204 has a cavity 244 for accommodating the battery 212 and has openings 222 and 224 allowing electrical connectors from the PCB assembly 206 to electrically connect with the reservoir module 202. The lower cover 220 further has couplers 246, 257, which can contain one, two, or more bent lips (or angled ledges because they are ledges or lips that are bent at an angle). Coupler 257 at the anterior end is not visible from
The reservoir module 202 is typically a disposable unit that can be discarded after use with appropriate procedure. The reservoir module 202 has a rigid inner upper portion 248 and has a less rigid outer upper portion 252 surrounding the inner upper portion 248 laterally and at the anterior end 233 and the posterior end 235. The inner upper portion has a generally layer shape. At one end of the device, the inner upper portion 248 has coupler receptor 247 having one or more openings 254 for lockingly receiving the coupler 246 of the electronic module 204. At another end of the device, another receptor 256 with opening(s) is present to lockingly receive another coupler insert(s) (not shown because it is hidden in the perspective view) extending from the lower cover 220 of the electronic module 204. The couplers at the two ends 233, 235 can have different structures for securing the two modules together. The couplers at the two ends can both have a single insert and receptor hole, or two or more inserts and receptor holes, or one end can have inserts and receptor holes different from the other end. Inserts and receptor holes can be located at either the electronic module side or the reservoir module side.
A cavity 258 in the inner upper portion 248 provides for space to accommodate the portion of the lower cover protecting the battery 212. Openings 260, 262 securely accommodate electrical connectors 263, 265 that provide electrical connection between the electrical connectors of the electronic module 204 and the electrode current distributor 285, 287. The electrical connectors 263, 265 have grooves or other securing features for securing them to the inner upper portion 248 at the openings 260, 262 and ensuring good electrical connection and, optionally, mechanical securing connection. The openings 260,262 can have rims around them to fit into the grooves of the electrical connectors 263, 265 for interference fit for securing together, or for ensuring good electrical connection by digging into the material of electrical connectors 263, 265. The electrical connectors 263, 265 can be made of metal or carbonized polymer to make them conductive. Alternatively, the electrical connectors 263, 265 can be comolded with the inner upper portion 248.
The inner upper portion 248 in the reservoir module 202 and the lower cover 220 in the electronic module 204 can be made with relatively stiff material, preferably electrically insulating polymeric material so that they can be coupled together to provide a sturdy support structure for the PCB assembly 206 and the flat flange (or wing) 272 of the outer upper portion 252 in the reservoir module 202. A layer of adhesive can be provided under the flat flange (or wing) 272 for attachment to the body surface. Useful material for making the inner upper portion 248 and the lower cover 220 include polyethylene, polypropylene, polyethylene terephthalate, polystyrene, and the like. Glass fibers, glass particles, silica, and the like can also be included in the polymeric material to provide more stiffness. When two materials are molded together, they are selected so that they are compatible for comolding, e.g., having similar thermal and chemical property. Further, pigments and other material can also be included in the construction material for the pieces that provide mechanical support. The stiff material also provides a means to create secure mechanical attachment that may be independent of the electrical connection.
The outer upper portion 252 in the reservoir module 202 includes a cutout 268 for receiving and securing the more rigid inner upper portion 248. Means for securing the various portions and pieces together can include couplers such as mating insert and receptors, adhesive, frictionally interfering edges, etc. Towards the posterior end 235, the outer upper portion 252 includes an upwardly extending ridges 264, 266. The ridges 264, 266 edge a channel 267 through which the posterior portion of the electronic module 204 can be received. The ridges 264, 266 each have a narrowing portion 240C and narrow portion 242C corresponding to and for receiving the narrowing portion 240B and narrow portion 242B of the lower layer 226 of the upper cover 218 in the electronic module 204. Further, the narrowing portion 240C and narrow portion 242C of the outer upper portion 252 of the reservoir module 202 correspond to and intimately match fit the narrowing portion 240A and the narrow portion 242A of the of the upper layer 228 (of the upper cover 218) in the electronic module 204 to provide a seam that is liquid resistant. The seam also provides visual indication that the electronic module 204 and the reservoir module 202 are properly and completely assembled. The ridges 264, 266 run generally from about the posterior end 235 of the outer upper portion 252 to half way or more, preferably to about 50-75% the longitudinal length of the reservoir module 202. Because of the narrowing portion 240C and narrow portion 242C of the outer upper portion 252 the ridges 264, 266 have a width (i.e., in a direction inwardly toward each other) in the lateral direction.
The outer upper portion 252 also has a frame 270 framing the cutout 268. The ridges 264, 266 rise above the frame 270 to receive the corresponding portions of the electronic module. The frame 270 has an inner perimeter to receive the inner upper portion 248 such that when the inner upper portion 248 of the reservoir module 202 is fitted into the outer upper portion 252, the inner upper portion can accommodate the lower cover 220 of the electronic module 204. Towards the anterior end 233, where the ridges 264, 266 are absent, the wide portion 238A of the upper layer 228 in the electronic module 204 can match with the frame 270 to provide a seam that is tight to indicate properly assembly and prevent ingress of foreign material. The outer upper portion 252 in the reservoir module 202 has a thin, generally flat annular flange 272 extending from the frame 270 all around to provide a lower surface 274 under the flat annular flange 272 for adhesive attachment to a body surface (e.g., human skin) when the device 200 is applied to the patient. Adhesive is not shown in
In this embodiment, the reservoir module 202 has reservoirs (preferably hydrogel) 276, 278 on the under side of the reservoir module 202 for contacting body surface of a patient for electrotransport of ions. A lower layer 280 in the reservoir module 202 is located at and secured to the underside of the upper inner portion 248. The lower layer 280 has downwardly facing cavities 283 for accommodating current distributors 285, 287 and reservoirs 276, 278. If desired, a tab 281 can extend off one end (e.g., posterior end 235) of the lower layer 280 in the reservoir module 202. An authorized person (such as a medical worker, e.g., doctor or nurse) can grasp the tab 281 to pull off the lower layer 280 with the reservoirs 276, 278 from the reservoir module 202 for disposal according to controlled pharmaceutical disposal regulations after the prescribed electrotransport delivery by the device 200 is completed. In this way, the risk for drug abuse through illicit use of the device is reduced.
Although it is possible to include electronic components in the reservoir module, to reduce the complexity of the reservoir module, reduce the risk of electronics failing because of corrosion due to the presence of liquid and moisture, and result in easier manufacturing processes, it is preferred that the reservoir module contains no active electronic components such as transistor, integrated circuit, operational amplifier, etc. Active electronic components are those that can provide gain in an electrical circuit, such as transistors, field effect transistors, triodes, etc. Preferably the only electrical components present in the reservoir module are nonactive components. In some embodiments, the only electrical material present in the reservoir module is conductor leading to the electrode that connect to a reservoir.
The upper layer 228 in the electronic module 204 match and fit tightly with the outer upper portion 252 in the reservoir module 202 to result in an inverted-saucer-shaped device 200.
Preferably, the upper layer 228 in the electronic module 204 and the outer upper portion 252 in the reservoir module 202 are both made with the same resilient material so that when the electronic module 204 and the reservoir module 202 are fitted together they form a unit that looks as if it is made of the same material and the dome surface is smooth or continuous (except for the groove like seam) where the ridges 264 meet with the upper layer 228 of the upper cover 218. Thus, the whole device looks like a generally uniform inverted saucer. The inverted-saucer shape is uniform and symmetrical except for the small transparent/translucent window portion 234 for the light or digital display and the small button cover portion 230. Here, the embodiment has an oblong inverted-saucer shape. The button is recessed to help to prevent inadvertent activation of the switch. It is contemplated that other inverted-saucer shapes are possible, e.g., having a planer outline in shapes of circle, polygon, etc.
The narrowing portion 240C of the outer upper portion 252 of the reservoir module 202 provides space to receive the posterior end of the electronic module 204. Thus, a user can first easily place the posterior end of the electronic module 204 into the narrowing portion 240C of the outer upper portion 252 since the narrowing portion 240C is wider than the posterior end of the electronic module 204. Guided by the ridges 264, 266, the user can then easily guide and push the posterior end of the electronic module 204 to slide down the channel 267 from the narrowing portion 240C through the narrow portion 242C toward the posterior end of the reservoir module 202 until the coupler 246 of the electronic module 204 loosely engages the coupler 247 of the reservoir module about the posterior end 235. Then the electronic module 204 and the reservoir module 202 can be pressed together in a pivotal motion to firmly engage the couplers at both the anterior end 233 and the posterior end 235. The couplers can be made with hooks, buttons, barbs, angled ledges, and the like to provide a click-fit or snap-fit to make the engagement permanent when the electronic module 204 and the reservoir modules are firmly pressed together. One kind of insert that can also be used is bar-shaped or has a cross section of a slot U that can be press-fitted to insert into a channel-shaped receptor. In the snap-fit or click-fit, one piece can be inserted into another with a snap or click as a resilient portion of a piece is squeezed initially by a restriction and suddenly released from the squeeze once the portion has passed the restriction. In certain designs, the coupler can be designed so that it is not reengageable. For example, the insert can have a barb or hook that if it is pulled back after insertion into a receptor the barb or hook will rip or distort the receptor so that if reinserted into the receptor the receptor will no longer hold or retain the insert. Alternatively, the barb or hook can be designed to break if pulled so that it cannot reengage with the receptor. Such designs may be used to prevent illicit reuse the device or the reservoir module. If desired, the couplers 246, 247 can be directly and firmly pressed together without first engaging loosely.
In
Further embodiments in which other changes are made to the above-described embodiments are possible. For example,
Although the many of the couplers 246, 247, 256, 257 described above are permanent couplers that once they are firmly pressed together the couplers from the electronic module lock permanently with the corresponding couplers from the reservoir module, it is contemplated that disengageable couplers (e.g., snap button type couplers with a bulb insertable into a receptor hole) can also be used. Devices in which the modules are permanently coupled provide an advantage that the unit is sturdy and the internal electronics and other features are well protected from mechanical disturbance or chemical intrusion and to provide secure electrical and mechanical engagement. Devices in which the modules are separable after use provides the advantage of reusing the electronic module.
The reservoir of the electrotransport delivery devices generally can contain a gel matrix, with the drug solution uniformly dispersed in at least one of the reservoirs. Obviously, other types of reservoirs such as membrane confined reservoirs are possible and contemplated. The application of the present invention is not limited by the type of reservoir used. Gel reservoirs are described, e.g., in U.S. Pat. Nos. 6,039,977 and 6,181,963, which are incorporated by reference herein in their entireties. Suitable polymers for the gel matrix can comprise essentially any synthetic and/or naturally occurring polymeric materials suitable for making gels. A polar nature is preferred when the active agent is polar and/or capable of ionization, so as to enhance agent solubility. Optionally, the gel matrix can be water swellable nonionic material.
Examples of suitable synthetic polymers include, but are not limited to, poly(acrylamide), poly(2-hydroxyethyl acrylate), poly(2-hydroxypropyl acrylate), poly(N-vinyl-2-pyrrolidone), poly(n-methylol acrylamide), poly(diacetone acrylamide), poly(2-hydroxylethyl methacrylate), poly(vinyl alcohol) and poly(allyl alcohol). Hydroxyl functional condensation polymers (i.e., polyesters, polycarbonates, polyurethanes) are also examples of suitable polar synthetic polymers. Polar naturally occurring polymers (or derivatives thereof) suitable for use as the gel matrix are exemplified by cellulose ethers, methyl cellulose ethers, cellulose and hydroxylated cellulose, methyl cellulose and hydroxylated methyl cellulose, gums such as guar, locust, karaya, xanthan, gelatin, and derivatives thereof. Ionic polymers can also be used for the matrix provided that the available counterions are either drug ions or other ions that are oppositely charged relative to the active agent.
Incorporation of the drug solution into the gel matrix in a reservoir can be done in any number of ways, i.e., by imbibing the solution into the reservoir matrix, by admixing the drug solution with the matrix material prior to hydrogel formation, or the like. In additional embodiments, the drug reservoir may optionally contain additional components, such as additives, permeation enhancers, stabilizers, dyes, diluents, plasticizer, tackifying agent, pigments, carriers, inert fillers, antioxidants, excipients, gelling agents, anti-irritants, vasoconstrictors and other materials as are generally known to the transdermal art. Such materials can be included by on skilled in the art.
The drug reservoir can be formed of any material as known in the prior art suitable for making drug reservoirs. The reservoir formulation for transdermally delivering cationic drugs by electrotransport is preferably composed of an aqueous solution of a water-soluble salt, such as HCl or citrate salts of a cationic drug, such as fentanyl or sufentanil. More preferably, the aqueous solution is contained within a hydrophilic polymer matrix such as a hydrogel matrix. The drug salt is preferably present in an amount sufficient to deliver an effective dose by electrotransport over a delivery period of up to about 20 minutes, to achieve a systemic effect. The drug salt typically includes about 0.05 to 20 wt % of the donor reservoir formulation (including the weight of the polymeric matrix) on a fully hydrated basis, and more preferably about 0.1 to 10 wt % of the donor reservoir formulation on a fully hydrated basis. In one embodiment the drug reservoir formulation includes at least 30 wt % water during transdermal delivery of the drug. Delivery of fentanyl and sufentanil has been described in U.S. Pat. No. 6,171,294, which is incorporated by reference herein. The parameter such as concentration, rate, current, etc. as described in U.S. Pat. No. 6,171,294 can be similarly employed here, since the electronics and reservoirs of the present invention can be made to be substantially similar to those in U.S. Pat. No. 6,171,294.
The drug reservoir containing hydrogel can suitably be made of any number of materials but preferably is composed of a hydrophilic polymeric material, preferably one that is polar in nature so as to enhance the drug stability. Suitable polar polymers for the hydrogel matrix include a variety of synthetic and naturally occurring polymeric materials. A preferred hydrogel formulation contains a suitable hydrophilic polymer, a buffer, a humectant, a thickener, water and a water soluble drug salt (e.g. HCl salt of an cationic drug). A preferred hydrophilic polymer matrix is polyvinyl alcohol such as a washed and fully hydrolyzed polyvinyl alcohol (PVOH), e.g. MOWIOL 66-100 commercially available from Hoechst Aktiengesellschaft. A suitable buffer is an ion exchange resin which is a copolymer of methacrylic acid and divinylbenzene in both an acid and salt form. One example of such a buffer is a mixture of POLACRILIN (the copolymer of methacrylic acid and divinyl benzene available from Rohm & Haas, Philadelphia, Pa.) and the potassium salt thereof. A mixture of the acid and potassium salt forms of POLACRLIN functions as a polymeric buffer to adjust the pH of the hydrogel to about pH 6. Use of a humectant in the hydrogel formulation is beneficial to inhibit the loss of moisture from the hydrogel. An example of a suitable humectant is guar gum. Thickeners are also beneficial in a hydrogel formulation. For example, a polyvinyl alcohol thickener such as hydroxypropyl methylcellulose (e.g. METHOCEL K100 MP available from Dow Chemical, Midland, Mich.) aids in modifying the rheology of a hot polymer solution as it is dispensed into a mold or cavity. The hydroxypropyl methylcellulose increases in viscosity on cooling and significantly reduces the propensity of a cooled polymer solution to overfill the mold or cavity.
Polyvinyl alcohol hydrogels can be prepared, for example, as described in U.S. Pat. No. 6,039,977. The weight percentage of the polyvinyl alcohol used to prepare gel matrices for the reservoirs of the electrotransport delivery devices, in certain embodiments can be about 10% to about 30%, preferably about 15% to about 25%, and more preferably about 19%. Preferably, for ease of processing and application, the gel matrix has a viscosity of from about 1,000 to about 200,000 poise, preferably from about 5,000 to about 50,000 poise. In certain preferred embodiments, the drug-containing hydrogel formulation includes about 10 to 15 wt % polyvinyl alcohol, 0.1 to 0.4 wt % resin buffer, and about 1 to 30 wt %, preferably 1 to 2 wt % drug. The remainder is water and ingredients such as humectants, thickeners, etc. The polyvinyl alcohol (PVOH)-based hydrogel formulation is prepared by mixing all materials, including the drug, in a single vessel at elevated temperatures of about 90 degree C. to 95 degree C. for at least about 0.5 hour. The hot mix is then poured into foam molds and stored at freezing temperature of about −35 degree C. overnight to cross-link the PVOH. Upon warming to ambient temperature, a tough elastomeric gel is obtained suitable for ionic drug electrotransport.
A variety of drugs can be delivered by electrotransport devices. In certain embodiments, the drug is a narcotic analgesic agent and is preferably selected from the group consisting of fentanyl and related molecules such as remifentanil, sufentanil, alfentanil, lofentanil, carfentanil, trefentanil as well as simple fentanyl derivatives such as alpha-methyl fentanyl, 3-methyl fentanyl and 4-methyl fentanyl, and other compounds presenting narcotic analgesic activity such as alphaprodine, anileridine, benzylmorphine, beta-promedol, bezitramide, buprenorphine, butorphanol, clonitazene, codeine, desomorphine, dextromoramide, dezocine, diampromide, dihydrocodeine, dihydrocodeinone enol acetate, dihydromorphine, dimenoxadol, dimeheptanol, dimethylthiambutene, dioxaphetyl butyrate, dipipanone, eptazocine, ethylmethylthiambutene, ethylmorphine, etonitazene, etorphine, hydrocodone, hydromorphone, hydroxypethidine, isomethadone, ketobemidone, levorphanol, meperidine, meptazinol, metazocine, methadone, methadyl acetate, metopon, morphine, heroin, myrophine, nalbuphine, nicomorphine, norlevorphanol, normorphine, norpipanone, oxycodone, oxymorphone, pentazocine, phenadoxone, phenazocine, phenoperidine, piminodine, piritramide, proheptazine, promedol, properidine, propiram, propoxyphene, and tilidine.
Some ionic drugs are polypeptides, proteins, hormones, or derivatives, analogs, mimics thereof. For example, insulin or mimics are ionic drugs that can be driven by electrical force in electrotransport.
For more effective delivery by electrotransport salts of certain pharmaceutical analgesic agents are preferably included in the drug reservoir. Suitable salts of cationic drugs, such as narcotic analgesic agents, include, without limitation, acetate, propionate, butyrate, pentanoate, hexanoate, heptanoate, levulinate, chloride, bromide, citrate, succinate, maleate, glycolate, gluconate, glucuronate, 3-hydroxyisobutyrate, tricarballylicate, malonate, adipate, citraconate, glutarate, itaconate, mesaconate, citramalate, dimethylolpropinate, tiglicate, glycerate, methacrylate, isocrotonate, β-hydroxibutyrate, crotonate, angelate, hydracrylate, ascorbate, aspartate, glutamate, 2-hydroxyisobutyrate, lactate, malate, pyruvate, fumarate, tartarate, nitrate, phosphate, benzene, sulfonate, methane sulfonate, sulfate and sulfonate. The more preferred salt is chloride.
A counterion is present in the drug reservoir in amounts necessary to neutralize the positive charge present on the cationic drug, e.g. narcotic analgesic agent, at the pH of the formulation. Excess of counterion (as the free acid or as a salt) can be added to the reservoir in order to control pH and to provide adequate buffering capacity. In one embodiment of the invention, the drug reservoir includes at least one buffer for controlling the pH in the drug reservoir. Suitable buffering systems are known in the art.
Obviously, the present invention is also applicable where the drug is an anionic drug. In this case, the drug is held in the cathodic reservoir (the negative pole) and the anoidic reservoir would hold the counterion. A number of drugs are anionic, such as cromolyn (antiasthmatic), indomethacin (anti-inflammatory), ketoprofen (anti-inflammatory) and ketorolac tromethamine (NSAID and analgesic activity), and certain biologics such as certain protein or polypeptides.
A device according to the present invention can be made by forming the layers separately and assembling the layers into the electronic module and the reservoir module. The polymeric layers can be made by molding. Some of the layers can be applied together and secured. Some of the layers can be comolded, for example, by molding a second layer onto a first layer. For example, the upper layer and lower layer of the upper cover (or top cover) can be comolded together. Some of the layers can be affixed together by adhesive bonding or mechanical anchoring. Such chemical adhesive bonding methods and mechanical anchoring methods are known in the art. As described before, once the electronic module and the reservoir module are formed, they can be packaged separately. Before use, the two modules can be removed from their respective packages and assembled to form the device for electrotransport. The device can then be applied to the body surface by adhesion.
The above-described exemplary embodiments are intended to be illustrative in all respects, rather than restrictive, of the present invention. Thus the present invention is capable of many variations in detailed implementation that can be derived from the description contained herein by a person skilled in the art, e.g., by permutation or combination of various features. Although iontophoretic devices are described in detail as illustration for showing how an electronic module and an agent module are coupled and work together, a person skilled in the art will know that electronic module and agent module in other electrotransport devices can be similarly coupled and work together. All such variations and modifications are considered to be within the scope of the present invention. The entire disclosure of each patent, patent application, and publication cited or described in this document is hereby incorporated herein by reference.
The present application is derived from and claims priority to provisional applications U.S. Ser. No. 60/896,398, filed Mar. 22, 2007, which is herein incorporated by reference in its entirety.
Number | Date | Country | |
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60896398 | Mar 2007 | US |