Patent Publication Number: US-7211076-B2

Title: Medical device for fluid delivery having low fluid flow rate

Description:
FIELD AND BACKGROUND OF THE INVENTION 
   The present invention relates, in general, to drug delivery, and in particular, to a new and useful device for delivering drugs to the body of a patient at a very low fluid flow rate. The present invention also includes the method of manufacture of the novel drug delivery device. 
   Fluid delivery devices, and particularly, drug delivery devices are known. Additionally, it is also known within the fluid delivery or drug delivery field, that fluids, such as drugs, can be moved through helical flow paths. For example, U.S. Pat. No. 3,998,244 (Bentley) describes a drip irrigation valve with a helical flow path for the delivery of various agricultural liquids, such as fertilizers to be fed through an irrigation system. This particular system is useful for providing drip irrigation that conserves water, minimizes weed growth and facilitates the transport of the agricultural liquids through the irrigation system. 
   U.S. Pat. No. 4,176,683 (Leibinsohn) describes a flow regulator useful in apparatus designed for administering liquids to the body. The device is a presettable fluid flow regulator having an elongated sleeve of flexible material and a core within the sleeve having a helical recess of varying cross section carved or scored into the core. A ring on the outside of the sleeve has an internal diameter slightly less than the outer diameter of the sleeve and is used to squeeze the sleeve against the core to define a flow passage between the core and the sleeve. The volume of flow is determined by the longitudinal position of the ring along the sleeve. 
   U.S. Pat. No. 6,270,483 (Yamada et al.) describes a liquid discharge regulator and a liquid feeder that utilizes a liquid discharge regulator. The regulator has a channel spirally carved or formed on the surface of a passage forming member. The surface of the passage forming member is brought into close contact with the inner surface of a housing part wherein the channel functions as a liquid passage. The passage forming member is made of a plastic material by using injection molding manufacturing and mass production. The main purpose behind using the plastic material made exclusively through the injection molding process for the formation of the passage forming member is aimed at reducing manufacturing costs of the regulator. 
   U.S. Pat. No. 5,985,305 (Peery et al.) describes a back-diffusion regulating outlet consisting of a male threaded member in threaded relationship with a smooth interior surface of a reservoir thereby forming a helical flow path. As clearly shown, similar to the other prior art flow regulator devices, the regulating outlet consists of a solid core of material which serves as a male threaded member, i.e. a screw, that is in mating relationship with the smooth interior surface of the reservoir. 
   To date, there have been no fluid flow regulator devices, mechanisms or drug delivery devices using these type of mechanisms that can be provided or manufactured in an extremely efficient manner, easily and readily adaptable to any desired designed configuration, and having extremely low cost of manufacturing. 
   SUMMARY OF THE INVENTION 
   The present invention is directed toward the field of drug delivery and relates to a novel orifice feature, mechanism or drug regulator device such as an orifice device. The present invention also relates to a drug delivery device utilizing the novel orifice mechanism and includes a novel implantable pump, a novel drug delivery device such as a drug delivery catheter or a novel implantable drug delivery device such as an implantable drug pump. 
   For purposes of this disclosure, the term “drug” means any type of molecules or compounds deliverable to a patient to include being deliverable as a fluid, slurry or fluid-like manner. The term “drug” is also defined as meaning any type of therapeutic agent or diagnostic agent which can include any type of medicament, pharmaceutical, chemical compounds, dyes, biological molecules to include tissue, cells, proteins, peptides, hormones, signaling molecules or nucleic acids such as DNA and RNA. 
   One embodiment of the present invention is an orifice device such as an orifice mechanism or drug dispenser regulator or regulator feature (all commonly referred to herein as “orifice device” or “orifice mechanism” or “orifice”). In accordance with the present invention, the orifice device is used to deliver a drug and comprises an inner member having a proximal end and a distal end and a winding helically wound around the inner member. The winding and the inner member define a first channel for carrying a drug therethrough (an active channel). An inlet is at the proximal end of the winding and an outlet is at the distal end of the winding. 
   Another embodiment of the present invention is a device for delivering a drug wherein the device comprises a body having a proximal end and a distal end and an opening in the distal end of the body. An orifice mechanism is included at the distal end of the body and is in fluid communication with the opening. The orifice mechanism comprises an inner member having a proximal end and a distal end and a winding helically wound around the inner member. The winding and the inner member define a first channel for carrying a drug therethrough (an active channel) and an inlet at the proximal end of the winding and an outlet at the proximal end of the winding. 
   In this embodiment according to the present invention, the novel device is a drug delivery device such as a drug delivery catheter or an infusion port device such as an intravenous (IV) port or IV fluid or drug delivery device. 
   Another embodiment of the present invention is a novel implantable device for delivering a drug wherein the device comprises a housing and a source of drug contained within the housing. An orifice mechanism is located at, on or within the housing and fluidly communicates with the source of drug. The orifice mechanism comprises an inner member having a proximal end and a distal end and a winding helically wound around the inner member. The winding and the inner member define a first channel for carrying the drug therethrough (an active channel) and an inlet at the proximal end of the winding and an outlet at the distal end of the winding. The drug is carried by the orifice mechanism and dispensed outside of the housing. The novel implantable device according to the present invention is designed as either a temporary or a permanent device to be implanted in a patient&#39;s body, particularly, at any location on or within the patient&#39;s body such as a particular site within tissue or organs. 
   Another embodiment of the present invention is a novel method for manufacturing an orifice mechanism. The novel method in accordance with the present invention comprises the steps of providing a mandrel, i.e. any member which serves as an inner member or core, wherein the mandrel has a certain length. A winding is then helically wound around at least a portion of the length of the mandrel. The mandrel and the winding define a first channel for carrying a drug therethrough (an active channel). An inlet is at one end of the winding and an outlet is at another end of the winding for ingress and egress of the drug respectively. 
   All embodiments of the present invention are directed toward a simple orifice design that allows for exceptionally low fluid flow rates by creating an extremely long orifice with a very small cross-sectional area that is ideal for very compact spaces. The use of a helical winding for all embodiments of the present invention results in a simple helical wire wrap that creates a very long orifice and results in primary benefits such as simplicity, compactness, readily adaptable design and customizable designs, ease of manufacturing and low costs of parts for manufacturing. The flexibility and adaptability of the present invention is exhibited by the properties of the orifice in accordance with the present invention that can be easily modified, for instance, by selecting a winding (comprised of any desired wire type) using wires of different diameters and also by varying the length of the helix (helical winding). Assembly and manufacturing of the orifice in accordance with the present invention is extremely flexible and simple especially since no precision machining is required such as the precise machining or complex and expensive injection molding equipment associated with the prior art devices and their manufacturing methods. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is an elevated side view of an orifice device in cross-section having a two-channel design in accordance with the present invention; 
       FIG. 1B  is an enlarged view of a portion of the orifice device of  FIG. 1A  showing a coil as part of a winding and having a circular-shaped cross-section; 
       FIG. 2A  is an elevated side view of an alternative embodiment of an orifice device in cross section having a one-channel design in accordance with the present invention; 
       FIG. 2B  is an enlarged view of a portion of the orifice device of  FIG. 2A  showing a coil as part of a winding and having a circular-shaped cross-section; 
       FIG. 3  is an enlarged view of a portion of the orifice device of  FIG. 1A  wherein the coil has a hexagonal shape in cross-section; 
       FIG. 4  is an enlarged view of a portion of the orifice device of  FIG. 2A  wherein the coil has a hexagonal shape in cross-section; 
       FIG. 5  is an enlarged view of a portion of the orifice device of  FIG. 1A  wherein the coil has an octagonal shape in cross-section; 
       FIG. 6  is an enlarged view of a potion of the orifice device of  FIG. 2A  wherein the coil has an octagonal shape in cross-section; 
       FIG. 7  is an enlarged view of a portion of the orifice device of  FIG. 2A  wherein the coil has a triangular shape in cross-section; 
       FIG. 8  is a view in cross-section of an implantable drug delivery device having an orifice mechanism in accordance with the present invention; and 
       FIG. 9  is a side view of an elongated drug delivery device having an orifice mechanism in accordance with the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention is directed toward a novel orifice mechanism, generally designated  200 , (interchangeably and commonly referred to herein as “orifice mechanism”, “orifice feature”, “orifice”, “regulator”, “regulator mechanism”, “regulator device”, or “orifice device”) such as reflected in embodiments of the present invention shown in  FIGS. 1A ,  1 B,  2 A,  2 B,  FIG. 3 ,  FIG. 4 ,  FIG. 5 ,  FIG. 6 ,  FIG. 7 . 
   The present invention is also directed toward a novel drug delivery device such as an implantable device, generally designated  100 , shown in  FIG. 8  and includes any type of implantable device such as an implantable drug delivery device, implantable drug elusion device, implantable drug delivery pumps or the like. The novel drug delivery device  100  of this embodiment also includes the novel orifice mechanism  200 . 
   The present invention is also directed toward a novel drug delivery device  150  having an elongated body  155  utilizing the orifice mechanism  200  in accordance with the present invention which is used at a desired location on the body  155  of the drug delivery device  150  such as shown in  FIG. 9 . The drug delivery device  150  in accordance with the present invention in this embodiment shown in  FIG. 9  is directed toward drug delivery devices such as drug delivery catheters having elongated and/or flexible bodies and also include intravenous (IV) drug catheters such as IV drug catheters or IV drug delivery ports or local drug delivery catheters. 
   The present invention is also directed toward a novel method of manufacturing the orifice mechanism  200  in accordance with the present invention and as best illustrated in  FIG. 1A  and  FIG. 2A . 
   As best shown in  FIGS. 1A ,  1 B,  2 A and  2 B, the novel orifice device or mechanism  200  in accordance with the present invention has a first end or proximal end  205  and a second end or distal end  207  respectively. The first component of the orifice mechanism  200  in accordance with the present invention is an inner member  210  which serves as an inner core for the device  200  and is used as a mandrel in the manufacturing method in accordance with the present invention. The inner member  210  has a length of any desired dimension and a winding  220  comprising a wire strand (wire)  222  helically wound or helically wrapped around the inner member (mandrel)  210  along any desired portion of the inner member  210 . For example, the wire  222  of the winding  220  extends from the proximal end  205  to the distal end  207  of the orifice mechanism  200  as illustrated in  FIGS. 1A and 2A , however, the winding  220  can be located along any portion of the length of the inner member  210  and comprises any desired width or dimension along the length of the inner member  210 . 
   The wire  222  of the winding  220  is wound or wrapped around the inner member  210  in any desired or customized fashion in order to create any desired pitch (channel depth) and amplitude (distance between adjacent individual strands of wire  222 ) in order to customize a first drug delivery channel or inner drug delivery channel  230 . This first drug delivery channel is also known as an active channel. The first drug delivery channel  230  is an interior channel formed by the individual strands of the wire  222  of the winding  220  and an outer member  226  which is an exterior surface placed over and around the winding  220  and inner member  210 . The outer member  226  serves as an exterior surface which constrains the winding  220  (and individual strands of wire  222 ) and the inner member  210  such that the outer member  226 , the wire  222  of the winding  220 , and the inner member  210  (mandrel) define a second drug delivery channel or exterior channel formed by the remaining or unfilled interstices or interstitial spaces. The second drug delivery channel is also an active channel. The outer member  226  can be any type of member such as a sleeve or a tube as relevant examples, and can be made of any material such as a polymer material, for instance, PTFE, or even be made entirely of an adhesive material such as a glue. 
   The wire  222  is made of a degradation resistant material in order to resist erosion or degradation by the constituents or properties of the drug or by exerted forces applied by the drug  108  ( FIG. 8 ) when delivered or channeled through the interior channel  230  ( FIGS. 1A ,  1 B,  2 A and  2 B) and the exterior channel  240  ( FIGS. 1A and 1B ). Examples of degradation resistant materials for use with the wire  222  in accordance with the present invention include materials such as a nickel titanium alloy, i.e. Nitinol (NiTi), stainless steel alloys, plastic or other types of relevant polymers. As best illustrated in  FIGS. 1B ,  2 B,  3 ,  4 ,  5 ,  6  and  7 , the wire  222  comprises any desired cross-sectional shape or configuration. Although not limited to these particular depicted cross-sectional shapes or configurations, relevant examples of the wire  222  in accordance with the present invention include wire  222  having a circular-shaped cross-sectional configuration as shown in  FIG. 1B  and  FIG. 2B ; wire  222   a  having a hexagonal shape in cross-section as shown in  FIG. 3  and  FIG. 4 ; octagonal-shape wire  222   b  as shown in  FIG. 5  and  FIG. 6 ; and triangular-shape wire  222   c  in cross-section as shown in  FIG. 7 . 
   When manufacturing the orifice mechanism  200  in accordance with the present invention, the interior channel (the inside or interior set of interstices)  230  or exterior channel (the exterior or outside set of interstices)  240  can be blocked in order to created a one-channel or one-side design or approach in order to further reduce the flow of the drug  108  ( FIG. 8 ) or to ease the burden of manufacturing. For example, this can be accomplished without precise sizing of the outer member  226 , and instead can be accomplished through the use of a polymer material or glue as the outer member  226  in lieu of an outer member  226  as a sleeve or tube. Thus, in a one-channel design, channel filling material  242  ( FIG. 2B ,  FIG. 4 , and  FIG. 6 ) is used to occlude or block one of either the interior channel (interior interstices)  230  or exterior channel (exterior interstices)  240  as shown. For example, in the embodiments shown, it is the exterior channel (exterior interstices)  240  that is replaced by the channel filling material  242 , i.e. the polymer material or glue. Although not shown, alternatively, the channel filling material  242  is used to occlude, block or fill the interior channel (interior interstices)  230  as part of a one-channel design. Additionally, the channel filling material  242  can be either the same material as used with the outer member  226  or be made of a second different material. 
   Accordingly, in accordance with the manufacturing method of the present invention, the orifice device or orifice mechanism  200  is adaptable to a tailored or customizable manufacturing method determined by control factors in accordance with the present invention. Thus, the present invention allows for customizing these central factors upon demand and include overall length of the winding  220 , cross-sectional area of the wire  222  (to include the alternative wire embodiments  222   a ,  222   b  and  222   c ), shapes or configurations of all wire configurations, and dimensions of the interstices or channels, i.e. interior channel  230  and/or exterior channel  240 ; and the amount of constrain or fit of outer member  226  to include the dimensions, shape and specific material of the outer member  226 . Thus, all of these factors controlled by the manufacturing method in accordance with the present invention allows for a customized orifice or orifice mechanism  200  that allows for varying rates of fluid flow control or regulation for the drug  108  ( FIG. 8 ). 
   As a drug delivery feature, the orifice device or orifice mechanism  200  includes an inlet  234  located at the first strand of wire  222  at the inner member  210 , for example, located at the proximal end  205  of the orifice mechanism  200 . The inlet  234  is the starting point or entry point for ingress of the drug  108  ( FIG. 8 ) into the first channel or interior channel  230  for carrying and channeling therethrough and terminates in an outlet  236  at the last strand of wire  222  of the winding  220  at the opposite end of the winding  220 , for example, at the distal end  207  of the orifice mechanism  200 . The outlet  236  allows for the channeled drug  108  ( FIG. 8 ) to exit or egress from the last strand of wire  222  of the winding  220 , for example, at distal end  207 . As shown in  FIG. 1A , the inlet  234  and the outlet  236  will exist at the interior channel or first channel  230  and the second channel or exterior channel  240  respectively as shown such that both channels  230  and  240  are active channels. As shown in  FIG. 2A , the inlet  234  and the outlet  236  will exist for the first channel or interior channel  230  only. Thus, the channel filling material  242  of the outer member  226  prevents ingress, channeling and egress of any drug  108  through any other portion of the orifice device  200  except for the first channel or inner channel  230 , for example, channeling is only possible through the interior interstices defined by the interior channel  230 . Accordingly, in this example, inner channel  230  is the only active channel capable of channeling the drug  108  through its interstices. 
   Relevant examples of degradation resistant material for the winding  220 , i.e. wire  222  ( FIG. 1A ,  FIG. 1B ,  FIG. 2A  and  FIG. 2B ), wire  222   a  ( FIG. 3  and  FIG. 4 ),  222   b  ( FIG. 5  and  FIG. 6 ), and  222   c  ( FIG. 7 ), also include various types of metal such as stainless steel alloys, nickel titanium alloys (Nitinol, NiTi), MP35N, and Titanium as well as various types of polymers or plastics. 
   Moreover, any size or dimensions for the winding  220  and wire  222 ,  222   a ,  222   b  and  222   c  respectively can be utilized. For instance, one example of appropriate dimensions for the wire is to use wire having a strand with a width ranging from 0.001–0.050 inches. Additionally, another preferable example for the wire dimensions in accordance with the present invention, is to utilize a wire having strands with a width ranging from 0.004–0.005 inches. 
   The present invention also is directed toward an implantable drug delivery device, generally designated  100 , which includes implantable devices such as a drug delivery pump. In one example according to the present invention, the drug delivery device  100  is an implantable drug pump which utilizes the orifice mechanism  200  and a source of drug  108 . 
     FIG. 8 , shows orifice mechanism  200  in an implantable pump device  100  such as an osmotically driven ruminal bolus. The orifice  200  resides in space  103  which passes through a densifier  104 . The bolus is surrounded by a semipermeable membrane  105 . The semipermeable membrane  105  allows water to pass therethrough which is imbibed by swellable osmotic element  106  which abuts or contacts movable interface  107  and upon imbiding, the water exerts force upon moveable interface  107  which in turn forces the drug  108  out of the orifice  200  through the outlet  236 . 
   The semipermeable membrane  105  serves as a housing. Additionally, the membrane or housing  105  has an opening  110  therein and in fluid communication with the outlet  236  of the orifice mechanism  200 . This permits the drug  108  to be carried by and channeled out of the orifice mechanism  200  and the membrane or housing  105  respectively in order to provide systemic or localized drug delivery. 
   The present invention is also intended to be not only an implantable drug device, but also intended to be used as a temporary implant device, for example a device wherein all of the components of the device  100 , including the orifice mechanism  200 , are made of a biocompatible and biodegradable material. Additionally, the drug delivery device  100  is also intended to be used as a device for placement within a body cavity, for example, the nasal cavity, ear canal, mouth, sinus passageway, the eye to include any vitreous passageway, the rectum or the like. Furthermore, the drug delivery device  100  is also intended to be used at an exterior surface of the patient, for example, placed at a location somewhere on the patient&#39;s skin for local delivery of the drug  108  to an exterior treatment site on the skins surface or for absorption into the patient&#39;s bloodstream through the skin or directly into a wound. 
   In the drug delivery device embodiment illustrated in  FIG. 8 , the densifier  104 , housing/membrane  105 , swellable osmotic element  106  and moveable interface  107  (which can be a piston) operate as a driving system or pumping system for the drug  108  by working in combination to move the drug  108  into inlet  234 , through the appropriate interstices or channels (for instance, first channel and/or second channel), and out of the outlet  236  and housing  105  through the opening  110  in housing  105 . 
     FIG. 9  illustrates another embodiment of a drug delivery device, generally designated  150 , such as an intravascular device. Relevant examples of the device  150  include a catheter, intravenous (IV) port device or the like. In some instances in accordance with the present invention, the drug delivery device  150  includes a body  155 , such as an elongated body, having a proximal end  157  and a distal end  159  respectively and a lumen therein in fluid communication with the proximal end  157  and the distal end  159 . A distal end opening  164  is located at the distal end  159  of the body  155 . And, the orifice mechanism  200  is located on the body  155 , for example within the lumen of body  155  and at the distal end  159  and adjacent to and in fluid communication with the opening  164 . The body  155  serves as the outer member  226  ( FIGS. 1A–8 ) and provides similar function and is comprised of similar materials as used with the outer member  226  (detailed above). The outlet  236  of the orifice mechanism  200  is located near the opening  164  and is in fluid communication therewith such that the drug  108  is passed through the orifice mechanism  200  (as described above) and out of the outlet  236  and opening  164  respectively. 
   Additionally, the delivery device  150  includes a handle  170  located at the proximal end  157  of the body  155 . The handle also includes a control  174  for controlling movement of the distal end  159  of the device  150 . Relevant movement of the distal end  159  includes deflection of the distal end  159  and opening  164  in various directions, for example, in any desired direction or angle offset from the longitudinal access of the body  155 . Although not shown, the device  150  can either include the source of drug  108  at a location within the lumen body of  155  or can receive the source of drug  108  at any desired portion of the device  150 , for example, through an entry port in the handle  170  (not shown). Accordingly, an entry or access port in the handle  170  can be shaped to accommodate a standard needle syringe containing the source of drug  108  such that the drug  108  can be injected or infused into the body  155  of the device  150  through the entry or access port for feeding or supplying drug  108  to the orifice mechanism  200  for ultimate delivery through the opening  164  of the device  150 . In addition to the design and control factors mentioned above that are responsible for the fluid flow rate of the drug  108 , the drug  108  is also channeled or migrates through the orifice mechanism  200  through capillary action which is controlled by many of the parameters and features outlined above to include tightness of the winding  220  (helical coil), diameter or width of the strands of wire ( 222 ,  222   a ,  222   b  and  222   c  respectively) and viscosity of the drug  108  being delivered. All of these parameters can be adjusted in order to optimize the fluid flow rate for the drug  108 . Additionally, additives can be included with the drug  108  (in solution) in order to control the viscosity of the drug  108  thereby controlling the overall delivery fluid flow rate. 
   Moreover, as mentioned above, one benefit of the orifice mechanism or orifice device  200  in accordance with the present invention is the ability to achieve very low fluid flow rates through the use of a tight, economic and cost efficient manufactured winding  220 . Thus, the present invention allows for more efficient manufacturing, less parts and less manufacturing tooling normally associated with the traditional and more costly parts, tools and manufacturing methods associated with the prior art drug delivery devices. Accordingly, the present invention avoids these drawbacks associated with the prior art devices such as costly machining normally found with lathe machines, micro-drilling or even injection molding machines that are required for manufacturing these prior art devices. 
   It will be appreciated that the preferred embodiments described above are cited by way of example and the full scope of the invention is limited only by the claims which follow.