each array of microneedles 6 , as shown in fig1 , is mounted on a hollow , rigid chamber 8 which acts as a distribution reservoir . this is connected to a flexible polymer reservoir 2 containing a drug . when drug is forced out of the flexible reservoir 2 , it will enter this chamber 8 and then be distributed to each of the needles 6 , and enter the skin 24 ( fig1 ) through the bore 10 of each needle ( fig6 ). this hollow chamber 8 may be produced as an integral part at the time of fabrication of the needles 6 , using a single polymer or metal substrate for both the needles 6 and chamber 8 . design of the needle 6 will ensure the edge 12 which slices into the skin 24 is sharp and of the optimum geometry to ensure smooth penetration into the skin . a connection port 14 ( fig8 ) provided on this chamber 8 allows the flexible reservoir 2 to be interfaced directly to this chamber 8 though a docking and locking mechanism . the docking port 14 on the flexible reservoir component may be used for the purpose of filling the reservoirs 2 with the appropriate drug formulation . there may be a porous membrane or septum ( not shown ) between the reservoir 2 and the microneedle 6 and chamber 8 section , which will prevent drug from escaping the flexible reservoir 2 during storage but allow drug to pass through when the reservoir 2 is compressed . as can be seen in fig2 , there may be more than one channel 4 leading from the reservoir 2 to the microneedle chamber 8 . the microneedle 6 and reservoir 2 arrays can be arranged on a thin polymer film with small , discrete reservoirs 2 or alternatively long , linear reservoirs 2 , as schematically shown in fig5 . the rollers 16 are mounted in a frame ( not illustrated ) that holds them at a fixed spacing from one another with their axes parallel , while leaving the rollers 16 free to rotate . as shown in fig9 - 12 , the rollers 16 will be stabilised by a rigid track 22 along which they will glide , maintaining firm and even pressure across the surface of the reservoir / needle combination . the track 22 is housed in a frame 26 also composed of a rigid material . the rollers 16 are immediately interfaced to a belt 18 which may be rubber , plastic or metallic in composition . the underside of the belt 18 has teeth ( not shown ) which slot onto teeth ( not shown ) on the rollers 16 to facilitate their movement . as shown in fig1 , the rollers 16 may not be completely cylindrical and have one or more parts of the surface 32 proud of the main body 16 of the roller to enhance the force exerted at the point at which the proud portion 32 of the roller is directly above the reservoir 2 and / or needle 6 . alternatively , they may be mounted eccentrically about their axis of rotation . the rollers 16 may be driven either by some form of linear actuator such as shape memory wire , or a micro - mechanical system ( not shown ), or by hand with a suitable casing 28 to allow firm grip to be established on the device with even distribution of pressure as shown in fig1 . the belt 18 has an area designated for the needle / reservoir patch 40 to be adhered . adhesive is standard , pressure - sensitive adhesive , and one which may be easily removed when the patch 40 is removed from the applicator . the overall dimensions of the motorised patch will be variable depending on the application . however the patch / applicator and combined electronics and actuation mechanism may be as small as a few mm in thickness . in use , the device is attached to a suitable area of skin , for example by tightly strapping the device to a limb . attachment for a belt or strap shall exist which may be used to secure the applicator / patch on a limb of a patient , and may be fastened using hook - and - loop fastener or an adjustable strap mechanism . the conveyor mechanism is activated so that the conveyor moves forward along the track in the direction indicated by arrow 20 and the belt 18 rotates , so that the needles 6 are successively eased under the belt 18 and brought into contact with the skin surface 24 at which point the needles 6 gently pierce and penetrate the skin 24 as they rotate about the arc of the leading roller 16 . as the conveyor continues to move forwards , the belt 18 unwraps from the first roller 16 to lie against the skin 24 . the longitudinal position of the needles 6 relative to the skin 24 remains fixed , thereby avoiding tearing . as the last roller 17 in the set passes the needles 6 , the belt 18 is taken up onto the last roller 16 , thereby withdrawing the needles 6 from the skin 24 . the rollers 16 , 17 supporting the belt act to compress the reservoir 2 containing the drug against the skin 24 at a point after the microneedles 6 have penetrated the skin 24 , forcing the contents of the reservoir 2 into the skin 24 via the bore 10 of the needles 6 . the rollers 16 , 17 may also exert pressure on a reservoir 2 and microneedle 6 simultaneously depending on the relative location of the reservoir 2 and needles 6 . alternatively the rollers 16 , 17 can be smaller in diameter such that a single roller is responsible for maintaining pressure on the reservoir 2 whilst another is responsible for exerting pressure on the needles 6 . subsequent pressing of each reservoir 2 by each roller 16 , 17 ensures all drug is delivered . fig1 illustrates a patch for withdrawing fluid samples from a patient for analysis , instead of delivering an agent into the patient . the patch comprises a reservoir 2 formed from flexible channels 4 , which have sufficient resilience to remain normally inflated and are directly interfaced to the microneedle array 6 . after the hollow needles 6 of the array have been inserted into the skin 24 , the passage of the rollers 16 squeezes the channels 4 against the skin 24 , thereby expelling air from the reservoir 2 through non - return valves 34 at the end of the reservoir 2 that is remote from the needles 6 . as the rollers 16 move off the reservoir 2 the resilient channels 4 attempt to spring open again but air cannot enter them via the non - return valves 34 . this causes a drop in pressure in the reservoir channels 4 and hence within the bores 10 of the needles 6 with which the channels 4 are interfaced , with the result that interstitial fluid or blood is withdrawn from the patient via the needles 6 . a suitable sensor system 36 can be incorporated in the patch or interfaced with it to allow for in situ and real time diagnostics / measurements to be undertaken using appropriate microprocessor controls and off - the - shelf sensor components . all references , including publications , patent applications , and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein . the use of the terms “ a ” and “ an ” and “ the ” and similar referents in the context of describing the invention ( especially in the context of the following claims ) is to be construed to cover both the singular and the plural , unless otherwise indicated herein or clearly contradicted by context . the terms “ comprising ,” “ having ,” “ including ,” and “ containing ” are to be construed as open - ended terms ( i . e ., meaning “ including , but not limited to ,”) unless otherwise noted . recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range , unless otherwise indicated herein , and each separate value is incorporated into the specification as if it were individually recited herein . all methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context . the use of any and all examples , or exemplary language ( e . g ., “ such as ”) provided herein , is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed . no language in the specification should be construed as indicating any non - claimed element as essential to the practice of the invention . preferred embodiments of this invention are described herein , including the best mode known to the inventors for carrying out the invention . variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description . the inventors expect skilled artisans to employ such variations as appropriate , and the inventors intend for the invention to be practiced otherwise than as specifically described herein . accordingly , this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law . moreover , any combination of the above - described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context .
a drug delivery device that delivers pharmacologically active substances transdermally using microneedles arranged on a belt mounted rotatably about a plurality of rollers , the microneedles having an associated drug reservoir mounted on the belt which is compressed when the needles and belt are brought into contact with the skin .