MXPA00004326A - Intravesical infuser - Google Patents

Abstract

A drug-infusing device is implanted into a body cavity such as a bladder. The device is implanted in an uninflated, low profile state. After insertion into the body cavity, the device is filled with a substance, such as a drug, and assumes an increased profile. After the device is filled, it is allowed to float freely within the body cavity. Alternatively, the device can be tethered to a wall of the body cavity. The device delivers the drug at a controlled rate over an extended period of time. In order to deliver the drug at a controlled rate, the device preferably has a pressure-responsive valving member. The flow resistance of the valving member is responsive to the pressure at which the drug is stored within the infusing device. The resistance of the valving member decreases as the pressure within the infusing device decreases, thereby providing a resultant controlled flow rate.

Description

INTRAVESICAL INFUSOR BACKGROUND OF THE INVENTION I. Field of the Invention The present invention relates to an infusor suitable for use within the bladder and methods for using the mfusor. II. Description of the Related Art Delivery of drugs to the bladder is typically done systemically. The systemic delivery of drugs through methods of oral, intravenous, intramuscular or transdermal administration carries with it the obvious rejections of any systemic treatment, such as side effects. The drug can also be metabolized or altered by physiological processes and the last amount of active drug that reaches the bladder can be reduced. In addition, because many drugs are not well tolerated systematically, the dose should be limited, thus reducing the total effective dose that reaches the bladder. The delivery of drugs to the bladder can also be carried out by retrograde injection of the drug into the bladder by means of a catheter. However, the retrograde introduction of the drug by means of a urethral catheter is adequate only in limited situations and has inherent rejections. See for example, Pharmacokinetics of the Intravesical Taxol Bladder, Song, D, ientjes, MG, Au, JL, Cancer Chemotherapy and Pharmacology, 1997, 40 (4): 285-92; The Pharmacokinetics of Intravesical and Oral Oxibutinin Chloride, Massad, CA, Kogan, BA, Trigo-Rocha, FE, Journal of Urology, 1992, Aug. , 148 (2 Pt 2): 595-7; Advances in Delivery and Objective of Drugs, Goldstein, D, Lewis, C, Current Opinion in Oncology, 1991 Dec. 3 (6): 1096-104; and Intravesical Hyaluronic Acid in the Treatment of Refractory Interstitial Cystitis, Morales, A, Emerson, L, Nickel, JC, Urology 49 (Suppl 5A): 111-113, 1997. The retrograde introduction of drug through a urethral catheter is mainly used in a hospital or controlled care situation. It is not suitable for treatment of chronic urinary tract conditions. Stephen et al. , U.S. Patent No. 5,301,688, discloses a method for treating vein cancer through electromotive administration of drugs in the bladder through a catheter. This type of treatment is suitable mainly for care administered in internal or external patients, not for chronic treatment. Tsukada, U.S. Patent No. 5,219,334 discloses an infuser for connection to a catheter that is suitable for long term delivery in a patient through the catheter. This device requires cauterization - continuous in order to function properly.

Pryor et al. , U.S. Patent No. 5,062,829, discloses a helical device for insertion into a body cavity, for example, the rumen of a bovine. The helical device includes a drug that can be removed over time and that also includes a biodegradable portion so that, upon termination of the drug, the device can be broken and removed naturally. Garay et al. , U.S. Patent No. No. 4,925,446, discloses an infusion device having an annular shape that is suitable for delivering materials into the stomach for a prolonged period of time. None of these prior art devices cover the problem of intravesicular delivery of the drug when the intention is for this delivery to continue for a prolonged period of time while the patient maintains an active lifestyle. Two of the main causes of urge incontinence are detrusor instability and hyperreflexia. Oxybutynin is a pharmacological agent that has been used to treat urge incontinence with some success. This drug is an anticholinergic agent that blocks contraction to the bladder and has direct muscle relaxing properties. Unfortunately, this drug is associated with important side effects in oral administration, including dry skin, dry mouth, blurred vision, constipation and urinary retention. In patients with cardiovascular disease, oxybutynin can lead to tachycardia. Due to side effects, the accepted oral dose of oxybutynin is restricted to 10-15 mg per day. 5 Interstitial cystitis is a debilitating condition where the inside of the bladder becomes irritated, creating a sense of urgency and pain. The condition results in extreme frequency of urination, sometimes up to 50, 50 or more times a day and can lead to cystectomy. People suffering from interstitial cystitis can receive treatment through the administration of certain drugs, including pentosanpolysulfate, developed by Bene of Munich, Germany and distributed by ALZA Corporation of Palo Alto, CA under the trademark ELMIRON.

However, there is no satisfactory method of delivering the pentosanpolysulfate to a patient for a prolonged period of time while allowing the patient to enjoy a relatively normal lifestyle. An on-site delivery system is needed specific to treat the bladder and urinary tract disease to avoid the effects associated with these pharmacological agents and allow the patient to enjoy an active lifestyle. SUMMARY OF THE INVENTION In one aspect of the present invention, provides an implantable infusion apparatus comprising a container with a drug and an outlet opening with restricted flow in fluid communication with the drug in the container. The device also comprises a coating adapted to inhibit deposition of material in the device when it is implanted in a body cavity of a mammal. For example, the coating can inhibit the deposition of materials present in the urinary tract. The coating may be a sulfated polysaccharide such as pentosanpolysulfate. The coating may be a surface coating on the surfaces of the device exposed to the body at implantation. The coating can be impregnated in the device. In addition or alternatively, a coating may be applied to the device to increase its lubricity. The exit orifice with restricted flow can provide delivery of the drug for a period of at least 24 hours, 5 days, 15 days or more. The drug can have a liquid form and the device can deliver the drug at a rate of at least about 400 μl / hour. The device can assume a first form during implantation and a second after implantation when it is full. The first form can be usually elongated and the second can be curved. The container of the device can be elastomeric.

The drug within the device may be effective in treating incontinence such as the urge. For example, the drug may be oxybutynin. This can also be an anesthetic, analgesic, antibiotic or anticancer agent. In addition, the drug can be used to treat cystitis. The device may have a first and a second end. One of the ends may be floating or both ends may be floating. The device may have a size that fits across the urethra in the bladder of the mammal. Another aspect of the present invention relates to an implantable infusion device comprising an elongated elastomeric portion having a first and second end and adapted to contain a pressurized liquid. The device may also comprise a flow controller that provides an outlet orifice in fluid communication with the liquid in the elastomeric portion. The flow controller can provide controlled release of the liquid from the device. The device also comprises a relatively inextensible element that connects the first and second ends of the elastomer portion so as to allow a relatively straight configuration of the device when it is not filled with the liquid and to stimulate a curved configuration of the device when it is filled with liquid . The relatively inextensible element may be within the elastomeric portion. The elastomeric portion may include a wall and the relatively inextensible element may be associated with the wall. Alternatively, the relatively inextensible element can form a part of the wall. The relatively inextensible element can also be found outside the elastomeric portion. The implantable infusion device may further comprise an incrustation-resistant coating on the device. For example, the coating can be pentosanpolisulfate. The device may comprise a floating portion at the first end. In addition, the device may comprise a floating portion at the second end. Another aspect of the present invention relates to a system for implanting an infusion device. The system comprises an elongated infusion device adapted to change the shape when full. The system also comprises my introducer suitable for insertion in vivo in a patient and enclosed so that the infusion device can be released. A conduit is associated with the introducer and is releasably attached to the infusion device. The conduit is used to fill the infusion device with liquid in vivo. The duct is inside the introducer. The conduit is attached to a removable valve of the infusion device. For example, the detachable valve is a separator seal and the conduit includes a hole to puncture the separator seal. The device further comprises an insert located within the introducer adapted to push the infusion device distally from the introducer. Another aspect of the present invention relates to a method for delivering a drug to a patient. The method comprises the steps for delivering an infusion device into a patient's bladder, releasing the infusion device in the bladder to float freely therein and pouring a drug into the bladder from the freely floating infusion device. The infusion step comprises the step of pressurizing the drug with an elastomeric element and releasing the drug at a controlled rate from the infuser. The method also comprises the step of filling the infusion device with the drug while the device is in the bladder. The filling step induces the change of shape in the infusion device. The change of form includes a change of profile. The shape change is of a straight configuration when it is empty to a curved configuration when it is full. The delivery step comprises the step for inserting the infusion device through the urethra in the bladder in an unfilled state into an introducer, then releasing the infusion device from the introducer to the bladder. Alternatively, the delivery step comprises elongation of at least a portion of the infusion device from the introducer, and then filling the device into the bladder. In addition, the device is attached to the wall of the bladder. The method may also comprise the step for removing the infusion device from the bladder after the infusion step. The infusion device used with the method assumes a first shape when it is empty and a second shape when it is full. The removal step comprises the step of changing the shape of the infusion device from the second form to the first form, and then directing the infusion device out of the urethra. The change from the second form to the first form is carried out by allowing the drug in the device to be emptied by the infusion step. The change from the second form to the first form is made by opening a passage in the device that allows any remaining drug in the device to leave it. In this case, the method further comprises the step of directing the drug from the passage through a conduit and out of the bladder. Removing the device includes the passage of it out of the urethra with a flow of urine. Alternatively, removing the device comprises capturing and then removing the device. Pouring a drug into the bladder involves controlling the flow rate of the drug from the device in the bladder. Control of drug flow is carried out by means of a pressure-sensitive valve. For example, the drug is under pressure and the pressure-sensitive valve controls the flow by varying the area of a flow channel in inverse proportion to the pressure of the drug. further, flow control is further carried out by means of a flow resistance element placed in an upstream of the liquid flow path of the pressure sensitive valve, thereby reducing the pressure of the drug inlet to the valve sensitive to pressure. The infusion step of the method comprises pouring the drug into the bladder for at least 5 days. The drug used with the method is used to treat urge incontinence. For example, the drug may be oxybutynin. The drug is also used to treat pain, neuralgia or cystitis. The drug is an antibiotic or an anti-cancer drug. Another aspect of the present invention relates to an infusion device comprising a box, a drug inside the box, a flow controller to control the rate at which the drug can be poured from the box, and a coating of pentosanpolis sulfate. on the device. The drug is pressurized and the flow controller is sensitive to pressure. The flow controller comprises a first pressure reducing element, a second pressure reducing element and a flow channel through the first and second pressure reducing elements. The second pressure reducing element can alter a cross-sectional area of the flow path in a manner inversely related to the drug pressure. In another aspect of the present invention, an implantable infusion device comprises an elongate container having a first shape wherein a transverse diameter of the elongate container allows it to pass through the urethra of a mammal. The elongated container has a configuration for stretching to a second shape that retains a pressurized liquid substance. A unidirectional valve assembly is placed on a first end of the elongated container and configured to admit the pressurized liquid substance into the elongated container while it is within the bladder of a mammal. An outlet orifice with restricted flow is configured to distribute the pressurized liquid substance from the elongate container while it is within the mammalian vein. In addition, the device comprises a fastening element for attaching the device to a wall of the bladder. The first form of the device can have a linear configuration with at least one axis of symmetry and the second form can have a curved configuration that does not have axial symmetry. The exit orifice with restricted flow provides a means for rapidly draining the pressurized liquid substance from the elongated container. The device comprises a capture element that is incorporated into a release mechanism that is configured to allow the exit orifice with restricted flow to rapidly drain the pressurized liquid substance from the elongate container. The exit orifice with restricted flow is configured to correspond to an envelope that is introduced into the bladder of the mammal so that the pressurized liquid substance is rapidly distributed through a channel of the envelope in place of the bladder of the mammal. The pressurized liquid substance is a diagnostic tool. The unidirectional valve assembly comprises a floating disc which in advance determines the obstruction of an inlet channel. The device comprises an element for securing the same to a wall of the bladder. In addition, the device comprises one or more features noted above. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a deflated intravesical infuser. Figure 2 is a perspective view of a mfuser according to the present invention, wherein the infuser is pressurized or inflated with a liquid, causing it to change shape. Figure 3 is a longitudinal cross-sectional view of the intravesical infuser of Figure 1, taken along line 3-3. Figure 3A is a longitudinal cross-sectional view of an alternative embodiment of the infuser of Figure 1, taken along line 3-3. Figure 4 is a detailed view of the proximal end of the infuser shown in Figure 3. Figure 5 is a longitudinal cross-sectional view of the proximal end of the infuser of Figure 3, in combination with an introducer device. Figure 6 is a schematic representation of a pressure sensitive valve for use in the present invention. Figure 7 is a perspective view of a pressure sensitive valve for use in the present invention. Figure 8 is a longitudinal cross-sectional view of the pressure sensitive valve of Figure 7, taken along line 8-8.

Figure 9 corresponds to the pressure sensitive valve as illustrated in Figure 8, which further illustrates the reduction of the cross flow area in the application of an external pressure P. Figure 10 is a cross section of an embodiment of the pressure sensitive valve illustrated in Figure 7, taken along line 10-10 of the Figure. Figure 11 is a cross section as in Figure 10, illustrating an embodiment having minimal flow channels. Figure 12 is a cross section as in Figure 10, illustrating an alternate embodiment of flow channel. Figure 13A illustrates an alternative embodiment of the pressure member of the mfuser device, in a cross section taken along line 13-13 of Figure 1. Figure 13B is a cross section of a second embodiment of the pressure element. Figure 13C is a cross-sectional view of the third embodiment of the pressure element. Figure 13D is a cross-sectional view of a fourth embodiment of the pressure element. Figure 13E is a cross-sectional view of a fifth embodiment of the pressure element. Figure 14 is a longitudinal schematic cross-sectional view of an intravesical infuser of the present invention illustrating an alternative use of an extensible element. Figure 15 corresponds to Figure 14, illustrates the application of tension to the extensible element to change the shape of the mfusor. Figure 16A is a schematic cross-sectional view of the mammalian bladder, illustrating placement of the infuser in the bladder. Figure 16B is a schematic cross-sectional view of the mammalian bladder, illustrating extracorporeal inflation or filling of the infuser with a drug while the infuser is inside the bladder. Figure 16C is a cross-sectional schematic view of the mammalian bladder illustrating the infuser of the present invention floating freely within the bladder. Figure 16D is a cross-sectional schematic view of the mammalian bladder, illustrating deflation of the mfusor within the bladder. Figure 16E is a schematic cross-sectional view of the mammalian bladder, illustrating the removal of the infuser of the present invention from the bladder. Figure 17A is a cross-sectional view of a valve assembly of the type illustrated in Figure 7, taken along line 10-10, wherein the valve assembly comprises compressible discs. Figure 17B corresponds to Figure 17A, illustrating the opening of the flow channels while the pressure falls on the infuser. Figure 18A illustrates a needle and valve valve assembly with reduced flow under high pressure. Figure 18B illustrates the needle valve of Figure 18A, with an enlarged flow channel under reduced infuser pressure. Figure 19 is a longitudinal cross-sectional view of an alternative embodiment of the intravesical infuser. Figure 20 is a detailed view of the proximal end of the infuser shown in Figure 19. Figure 20A is a cross-sectional view illustrating the slots in the unidirectional valve retention device of Figure 20. Figure 21 is a detailed view of the distal end of the infuser shown in Figure 19. Figure 22 is a longitudinal cross-sectional view of the proximal end of the infuser of Figure 19, in combination with an introducer device. Figures 23A-B are a perspective and sectional view of an alternative pressure sensitive valve for use in the present invention, respectively. Figure 24 is a perspective view of another alternative pressure sensitive valve for use in the present invention. Figure 25A is a schematic cross-sectional view of the mammalian bladder illustrating placement of the infuser illustrated in Figure 19 in the bladder. Figure 25B is a schematic cross-sectional view of the mammalian bladder illustrating the release of the infuser after extracorporeal inflation. Figure 25C is a schematic cross-sectional view of the mammalian bladder, which illustrates the recovery of the mfusor from inside the bladder. Figure 25D is a cross-sectional schematic view of the mammalian bladder, illustrating deflation of the mfusor within the bladder. Figure 26 illustrates a recovery device that can be used to retrieve the infuser illustrated in Figure 19 from the patient. DETAILED DESCRIPTION OF THE INVENTION The present invention includes a unique intravesical infuser device suitable for depositing in a body cavity such as a bladder. The device can be filled with a substance, which results in a change of form £ * r i-reversible to prevent emptying of the filled device or obstruction of the bladder neck. The device provides controlled site-specific delivery of the drug into the bladder for a prolonged period of time. With reference to Figure 1, infuser 10 has a proximal end 12 and a distal end 14. In general, for infusor 10 to be suitable for use in a human bladder, the length when deflated should be approximately 4 inches and have a margin of approximately 3 to 6 inches long. The diameter in the deflated condition of infuser 10 should be approximately 0.25 inches. Stretching between the proximal end 12 and the distal end 14, in a preferred embodiment, is an elastomeric pressure element 16 suitable for containing and pressurizing a liquid or liquid drug. The elastomeric pressure element 16 can be made of any polymer with suitable elastic medical quality and preferably made of medical grade dimethyl siloxane (silicone). For example, the elastomeric pressure element 16 can be a silicon tube class VI USP, 60 +/- 10 Tip A with a peroxide cure, having approximately an inner diameter of 3/16 of an inch and approximately an outer diameter of M in. The elastomeric pressure element 16 can also be made of other elastic materials such as coated or uncoated polyurethanes, polystyrenes, butyl rubber, latex rubber or other natural or synthetic elastomers. The elastomeric pressure element 16 may be about one-half inch shorter than the infusor 10. A proximal end cap 20 is provided to the proximal end 12. The proximal end cap 20 may be approximately 0.44 inches long and approximately 0.25 inches in diameter . A distal end cap 22 is similarly provided to the distal end 14 of the infuser 10. The distal end cap 22 is approximately 0.57 inches long and 0.25 inches in diameter. To secure the pressure element 16 to the proximal end cap 20 a proximal collar 24 is provided. Likewise, a distal collar 26 is provided to secure the pressure member 16 to the distal end cap 22 of the infuser 10. The cap proximal end 20, proximal collar 24, distal end cap 22 and distal collar 26 can be formed of any relatively rigid thermoplastic polymer, having long-term biocompatibility in vivo, such as GE Ultem 100 of General Electric of Pittsfield, MA. The infuser 10 can be assembled using a variety of adhesive compounds, such as an epoxy. A proximal opening 30 is provided at the proximal end 12 of the infuser 10, for introducing the liquid into the pressure element 16. The diameter of the proximal opening 30 may be approximately 0.1 inch. A distal opening 32 is provided at the distal end 14 of the infuser 10, through which the drug pressurized by the pressure element 16 leaves the infuser 10 at a controlled rate. The diameter of the distal opening 32 may be approximately 0.07 inches. Of course, modifications and adaptations of the device are contemplated where both openings 30, 32 are at one end or where an opening serves for the purpose of filling, delivering and draining. Figure 2 illustrates infuser 10 in its full or inflated state. Because the empty infuser of Figure 1 is relatively straight in profile and the pressure element 16 is somewhat flaccid, the full infuser 10 illustrated in Figure 2 is stretched causing the pressure member 16 to be relatively stiff. The embodiment illustrated in Figure 2 includes an extendable member 34 that connects to the proximal end 12 and the distal end 14. The extendable member 34 may be made from a variety of generally inextensible materials., including wire, cloth or polymer. For example, the extendable member 34 may be a polyester batten approximately 0.006 inches thick by 0.085 inches wide as supplied by Berwuick Industries, Inc. of Berwick, PA. When the pressure element 16 is inflated or filled with a substance, the tendency is for the pressure element to be stretched both radially and axially. However, the axial extension is inhibited by the expandable element 34. As a result, the infuser takes a non-linear profile. In the embodiment illustrated in Figure 2, the infuser 10 takes a crescent or annular shape as a result of the stress induced by the expandable element 34. When the device is used as an intravesical infuser 10, the non-linear shape can easily inhibit spontaneous or accidental undesirable emptying of the inflated full or inflated 10. In general, for infusor 10 to be suitable for use in human bladder, the inflation volume of infusor 10 is from about 30 cc to about 40 cc. However, in some cases, it may be convenient to increase the inflation volume above 60 degrees or decrease it below 10 degrees. Although the shape illustrated in Figure 2 is a crescent moon, it is understood that other shapes, including sinusoidal, helical, supercoiled and randomly bent forms are within the scope of the present invention. From another perspective, it must be understood that the change of form that prevents accidental emptying of the device is a change of profile. Thus, if the device has a cylindrical shape with a diameter of 6mm when implanted, for example, which allows it to pass quickly through the urethra, it may well have a crescent moon shape with an annular diameter of 150 mm, 200 mm or more when it fills in the bladder. This change in the profile itself can reduce the chance of accidental emptying. One characteristic of the shape change is that a first shape facilitates placement of the infuser in the bladder through the urethra and a second form prevents spontaneous emptying of the infuser. Preferably, the second form also facilitates urination by retaining a shape that does not obstruct the neck of the bladder. For example, in the embodiment described above, the first cylindrical shape has a diameter that is smaller than the diameter of the urethra so that it can be placed in the bladder through the urethra. Once inserted, the infuser in the second annular form does not pass and leaves the urethra, blocks the neck of the bladder or prevents the patient from urinating. As the contents of the device are distributed in the bladder, the device can experience at least a partial change in an inverted manner. The change of inverse form facilitates the removal of the device. In one embodiment, the device has memory so that the device does not return to its original shape by simply distributing its content. In this way, even after distributing all or some of the contents, the device retains a shape that does not leave the urethra or block the neck of the bladder. Figure 3 illustrates infuser 10 in a longitudinal cross-sectional view in a flaccid state. Infuser 10 illustrated in Figure 3 includes an optional capture element 36 at both proximal 12 and distal 14 ends of infuser 10. Capture element 36 may be a loop of suture material such as 2-0 suture, thermoplastic polymer, silicone , polytetrafluoroethylene, or any other suitable biocompatible material. Although the loop configuration is illustrated, any other suitable configuration can be used that can be attached or held by a recovery device. Those configurations would include molded handles or interlocking mechanisms in the infuser device itself. As seen in greater detail in Figure 4, the proximal end cap 20 is adapted to receive a hypodermic needle 38. The hypodermic needle 38 inserted in the proximal opening 30 can be elongated through the guide channel 40 to find an element of valve 42. In the illustrated embodiment, the valve element 42 is a separator seal. The valve member 42, when having a septum configuration, is preferably made of silicone or other biocompatible elastomeric or viscous material. For example, the valve element 42 can be made of a 2-part silicon encapsulation compound supplied by A.E. Yale Enterprises of San Diego, CA under part numbers VSI 1065A and VSI Hl PRO GREEN. The valve member 42 may be approximately 0.25 5 inches long and 0.161 inches in diameter. Spacer seals, such as valve element 42, will be punctured one or more times to allow access to the interior of a container, while resealing after the piercing device is removed. At the moment In the invention, the combination of the guide channel 40 and the spacer seal 42 tend to retain the infuser 10 firmly attached to the hypodermic needle 38 during the introduction of the infuser 10 into the bladder. Still referring to Figure 4, the proximal end cap 20 can usefully comprise a outer lining 44 which is generally cup-shaped. A needle hole 46 fits concentrically in the outer skin 44. The needle hole is tube-shaped with a small proximal end extending to the proximal opening 30 and defining the guide channel 40. while the needle hole 46 extends in a distal direction. An annular flange 50 extending radially outwardly from the guide channel 40 links the needle hole 46 to the interior of the outer skin 44. Thus, the needle hole 46 surrounding the guide channel 40 is attached to glue, ultrasonically welded or otherwise bonded suitably to the outer skin 44 in the proximal opening 30 and is also attached by means of the flange 50 to the distal portion of the outer skin 44. The embodiment of the proximal end cap 20 illustrated in Figure 4 further includes a septum fastener. 52 which sits concentrically within the distal end of the outer skin 44 and which extends distally therefrom. The proximal end of the septum holder 52 terminates in the annular flange 50. The distal end of the septum holder 52 is stretched distally from the outer liner 44, coaxially with the outer liner 44. In a preferred embodiment, the septum holder 52 includes protrusions. or slots 54 for retaining the pressure element 16 securely with the proximal end cap 20. The inner diameter of the annular septum holder 52 becomes narrow at the distal end thereof. When assembled in the outer skin 44 to abut the flange 50, the septum holder 52 compresses the spacer 42 against the flange 50 at the proximal end of the spacer 42 and against the narrower portion of the septum holder 52 at the distal end thereof. . The pressure element 16, which is preferably in the shape of a tube, slides on the outside of the distal portion of the septum holder 52. This is then secured in place in the proximal end cap by the proximal collar 24, providing a seal to leak tests. The retention of the pressure element 16 under pressure is facilitated by the projections or slots 54 in the septum holder 52. The proximal collar 24 can additionally secure the capture loop 36 by holding the ends of the capture loop 36 under the proximal collar 24. Similarly, the pressure exerted radially inwardly by the proximal collar 24 can be used to secure an extensible member 34. The extensible member 34 is preferably trapped between the pressure member 16 and the septum holder 52 by the pressure exerted by the the proximal collar 24 at the proximal end of the pressure element 16. With reference again to Figure 3, the distal end 14 of the infuser 10 provides controlled release of the drug from the pressure element 16 by means of the distal opening 32. In the illustrated embodiment, a linear resistor 56 is provided to control the flow of liquid from the interior of the p-element. 16 through the distal opening 32. In previous versions of the prototype of the infuser 10, the linear resistor 56 comprises a small cotton cord, suture or other suitable resistor element 60 surrounded by an impermeable coating 62. We find that the cotton thread for crochet surrounded by heat-shrinkable polyolefin material is a satisfactory linear resistor 56. A satisfactory cotton yarn for crochet is the white 4-thread cotton fiber for wounds of approximately 0.022 inches in diameter manufactured by Coats and Clark, Inc. of Greensville, South Carolina under part number Article C-44. A cotton crochet yarn manufactured by Coats and Clark, Inc. of Greensville, South Carolina under the trademark CROSHEEN may also be used. A satisfactory waterproof coating 62 is the heat shrinkable polyolefin with a 0.032 inch stretchable inner diameter supplied by Raychem, Menlo Park, CA. The resistance generated by the linear resistor 56 is a function of its length, diameter and the materials from which it is made, and for any given pressure, the flow rate for a linear resistor 56 in particular can be determined easily by empirical methods . For example, the suitable resistor element 60 can be from about 0.5 inch to 10 inches long. In the general case, it is typically useful if the flow rate of the infuser 10 remains constant within about +/- 50%, preferably +/- 30% or +/- 20% over a variety of pressure conditions. In a preferred embodiment of the invention, the end caps 20, 22 include air bags 64 to provide buoyancy. Of course, as an alternative for the use of airbags, the end caps 20, 22 could be made of low density material or could include air bags on the inside or outside of the end caps 20, 22 and other appropriate element to promote buoyancy. By making the end caps 20, 22 lighter than the rest of the infuser 10, the caps 20, 22 will tend to float. Because the urethra is located in the neck of the bladder, usually in the lower part of the bladder when a person is standing, the end caps 20, 22 will tend to float when the bladder becomes full and during urination. This, in turn, presents the intermediate curved portion of the curved infuser 10 at the exit of the bladder. Because this curved portion generally extends transversely to the direction of flow, it is unlikely that the inflated or inflated 10 will accidentally empty or obstruct the bladder neck while the infuser 10 is in a curved or arched configuration. with the floating end caps. The floating end caps 20, 22 also help to minimize or avoid irritation of the trigonal region and neck of the vein, thereby minimizing patient discomfort. Figure 5 schematically illustrates a method for introducing infuser 10 into the bladder. An outer wrap 66 is provided within which the infuser 10 can concentrically adapt when it is in a deflated or unfilled state. After the transurethral introduction of the outer envelope 66 into the bladder, the deflated infuser 10 passes through the outer envelope 66. Within the outer envelope 66 is located concentrically an expander 70 having a diameter approximately equal to that of the infuser 10. Finally, a hypodermic needle 38, positioned concentrically within the expander 70, is inserted into the separator 42 of the infuser 10 to retain the infuser 10 against the hypodermic needle 38 and prevent the loss of the infuser 10 during inflation or filling. The hypodermic needle 38 is connected at its proximal end to a liquid source (such as a liquid drug source) (it does not appear). With the outer wrapper in place in the bladder, the expander 70 and hypodermic needle are used to push the fuser 10 through the outer wrap 66 in the bladder. The liquid is then introduced through the hypodermic needle 38 to fill the pressure element 16 with liquid and induce a shape change of the infuser 10. After the infuser 10 is full, the hypodermic needle 38 is disconnected from the infuser 10 and it is taken out through expander 70. Infuser 10 can freely float within the patient's bladder. The expander 70 and the outer wrap 66 are then removed from the patient's bladder. Figure 19 is a longitudinal cross-sectional view of an alternate embodiment of the mtravesical infuser in a flaccid condition. The infuser 10 illustrated in Figure 19 includes an optional capture element 236 at the distal end 14. The distal end 14 of the infuser 10 is also used for normal delivery of drugs and for draining the drug., if necessary, during the removal process. The infuser 10 illustrated in Figure 19 allows the introduction of the liquid under pressure in the pressure element 16 through a unidirectional valve 242 at the proximal end 12. The unidirectional valve 242 prevents fluid from leaving the infusor through the proximal end 12 of the infuser 10 after the fluid was introduced into the infuser 10. As shown in more detail below, the unidirectional valve 242 eliminates the need for the hypodermic needle 38 to pierce the valve member 42 as shown in FIGS. 4 and 4. 5. The pressure valve 242 facilitates faster filling of the infuser 10 by eliminating the flow resistance in the hypodermic needle 38. The unidirectional valve 242 is shown in detail in Figure 20. A form of proximal end cap 220 is covered by an end cap stop 224 that fits more and is softer than the proximal end cap shape 220. The use of the most compliant material of the t Ope of end cap 224 reduces the trauma caused by contact of the proximal end 12 with the tissue. In one embodiment, the end cap stop 224 is polymeric material. The proximal end 12 has an opening 230 that allows access to a unidirectional valve inlet 246. When a lot of liquid pressure pushes a floating disc 244 into the distal end of the unidirectional valve inlet 246, the floating disc 244 moves. and moves away from the valve inlet 246 allowing liquid to enter a liquid chamber 250. The liquid in the liquid chamber 250 enters the opening of the pressure element 16 through the slots in a unidirectional valve holder 252. Figure 20A is a cross-sectional view illustrating more clearly four slots 254 in the unidirectional valve holder 252. The pressure generated by the pressure member 16 causes the floating disc 244 to obstruct the unidirectional valve inlet 246 at the end of the introduction of the liquid. A small spring 248 maintains a pressure against the floating disc 244 to maintain the unidirectional valve 242 closed even when the pressure within the liquid chamber 250 is approximately the same as the pressure within the aperture 230. The distal end 14 of the infuser 10 shown in detail in Figure 21. The distal end 14 includes the optional capture element 236. The capture element 236 is made of material similar to that described for the capture element 36 as is the suture 2-0. It is useful to connect the capture element 236 from the center of the distal end 14 so that the infuser 10 is aligned only with a pulling force applied to the capture element 236. The distal end 14 also includes a flow reducer 256 which measures the flow of the liquid of the pressure element 16 through a distal opening 232. The flow reducer 256 can be manufactured from a variety of sintered or porous metallic materials or polymer. For example, the 256 flow reducer can be a 0.062 inch diameter, 0.06 long titanium sintered cylinder with a size micron pore size as manufactured and supplied by Mott Corporation of Farmington, CT or superimposed 13 mm diameter porous polycarbonate membrane discs with 0.01 or 0.05 micron pore sizes manufactured and supplied by Osmonics of Livermore, CA, with numbers of catalog 10505 and 10501, respectively. The flow restrictor 256 is located within a flow reducer housing 280. The flow reducer housing 280 is within a distal end cap shape 222 by a valve seat. 226. The valve seat 226 seals an interior opening of the distal end cap shape 222 which restricts the liquid in the pressure element 16 from flowing through a flow channel 282 of the valve seat. An O-ring 286 seals the valve seat 226 towards the housing of flow reducer 280 preventing liquid from flowing through of the flow reducer 256 and not around the flow housing 280. A flow reducer housing spring 284 presses on the flow reducer housing 280 forcing it against the valve seat 226 by pressing on the O-ring 286 to maintain the seal integrity between the valve seat 226 and the flow reducer housing 280. The distal end cap shape 222 is covered by a distal end cap stop 228. The distal end cap stop 228 is made of a adaptive material that reduces the trauma caused by contact of the distal end 14 with the tissue. On the outlet side of the flow reducer 256, a fastener 288 holds the capture element 236. The capture element 236 exits the infuser 10 through the distal opening 232. The placement of the capture element 236 facilitates the removal of the infuser 10 allowing the device to exit or crawl out of the bladder through the urethra. If the capture element 236 is pulled out while maintaining sufficient opposite pressure against the stop of the distal end cap 228, the flow reducer housing spring compresses so as to release pressure on the O-ring 286. In this way , the liquid inside the pressure element 16 can flow around the flow reducer housing 280. This configuration facilitates rapid draining of the liquid content of the pressure element 16 which decreases the profile of the infuser 10 thus facilitating the removal of the device. Figure 26 illustrates a recovery device 270 that can be used to cool the infuser 10 of the patient. A capture element 276 is retractably positioned within a recovery channel 274. To remove the infuser 10, a wrap 272 is inserted into the bladder. Once it has been introduced, the capture element 276 is stretched in the bladder and engages the capture element 236. The capture element 276 retracts into the recovery channel 274 by pulling the distal end cap stop 228 in a sealed fit with an inlet of the channel 278. The compliant material that is used to form the distal end cap stop 228 facilitates sealing between the distal end 14 and the inlet of the channel 278. As the pressure against the infuser 10 increases, the flow reducer housing spring 284 compresses by releasing the pressure on the O-ring 286 and creating a fluid path from inside the pressure element to the elastomer 16 to the recovery channel 274. In this way, any liquid remaining inside the infuser 10 is it can drain from infuser 10 to lower the profile of infuser 10 for extraction through the urethra while preventing the introduction of fluid into the bladder. Figure 22 is a longitudinal cross-sectional view of the proximal end of the infuser 10 of Figure 19, in combination with an introducer device. An outer wrap 266 is provided in which the infuser 10 is adjusted or adjusted concentrically when it is in a deflated or non-full state. After the transuretal introduction of the outer envelope 266 into the bladder, the deflated infuser 10 passes through the outer casing 266 to the position shown in figure 22. Located concentrically within the outer casing 66 is an expander 262 having a diameter approximately equal to that of the outer cap stop 224 At the distal end of the expander 262 is a secure attachment fitting 260 that fits snugly to the opening 230 of the infuser 10. For example, the secure attachment accessory 260 can be an LUER accessory. The perfect fit of the secure coupling attachment 260 in the opening 230 of the infuser 10 prevents loss of liquid during filling or inflation. An introducer channel 264 located within the expander 262 provides a liquid path for a liquid source (not shown) connected to a proximal end of the expander 262. The liquid pressurized from the liquid source compresses the small spring 248 and displaces the floating disc 244 from the inlet of the valve 246. The liquid flows from the introducer channel 264 through the inlet of the valve 246, into the liquid chamber 250 and fills or inflates the infuser 10. When the filling is complete, the liquid pressure in the channel of the introducer 264 is reduced and the floating disc 244 returns to its original position obstructing the inlet of the valve 246. The secure attachment fitting 260 is disconnected from the infuser 10 and retracts to the expander 262. Retraction of the expander 262 releases to the infuser 10 so that it floats freely in the patient's bladder. The outer wrap assembly 266 and expander 262 is then removed from the patient. In preferred embodiments of the invention it is useful to provide a set of pressure sensitive valves to control the flow of the drug out of the pressure element 16 of the infuser 10. Due to the pressure profile of an elastomeric pressure element the infuser decreases over time, while the volume of the drug (and thereby the pressure) within the pressure element decreases, a linear resistor such as element 56 in Figure 3 provides a variable time flow. It is better to provide a relatively constant rate of delivery of the drug to the bladder. This can be carried out, in a preferred embodiment by means of pressure sensitive valves, as illustrated in Figure 3A. In Figure 3A, the infuser 10 is generally described in connection with Figure 3, where similar reference numbers reflect similar parts. However, towards the distal end 14 of the infuser 10, a pressure sensitive valve 74 which uses movable walls 86 to reduce the area of a flow channel 76 is used to control the flow of the liquid out of the infuser. Appropriate valve mechanisms are described in more detail in relation to Figures 6-12, any of the valves described could be adapted for use in the invention. The operation of a suitable type of pressure sensitive valve is illustrated in Figure 6. A pressure source Pl directs the liquid from a liquid container 72 to a valve assembly 74 through a flow channel 76. When the liquid reaches the valve assembly 74, this is subjected to an external and internal differential pressure that creates a flow resistance proportional to the differential pressure in question. Thus, with reference to Figure 6, the example pressure Pl in the liquid container 72 is also applied to the exterior of the valve assembly 74. This pressure Pl reduces the flow area of the flow portion of the channel 76 that is extends through the valve assembly 74 or otherwise increases the flow resistance through the flow channel 76, causing the pressure in the flow channel 76 to drop to a lower pressure P3 when it exits the valve assembly 74. The liquid continues along the flow channel 76 to the outlet 80 in a preferred embodiment, a linear resistor 82 is provided between the liquid container 72 and the valve assembly 74 within the flow channel 76. The linear resistor 82 may have a detailed construction in Figure 3YOU. , or alternatively, it can be any of the other convenient constructions, such as a spiral path, capillary tubes or a series of collateral passages. As seen in Figure 6 after the liquid passes through the linear resistor 82, the pressure Pl entering the linear resistor 82 was reduced to a lower pressure P2. Thus, when the pressure Pl is exerted on the valve assembly 74 (e.g., on the exterior of valve assemblies 74), the ability of the pressure Pl to restrict the flow channel 76 within the valve assembly 74 does not will be neutralized by the pressure P2 as effectively as if the pressure in the valve assembly 74 were Pl. Thus, by reducing the pressure within the valve assembly 74, the linear resistor 82 facilitates effective restriction of the liquid flow by means of the valve assembly 74. Note that in this type of pressure sensitive valve, the liquid flow is it can keep relatively constant despite variations in the pressure of the liquid container. This is because higher pressures (which ordinarily would facilitate greater flow) are neutralized by a greater restriction of the flow channel 76 through the valve conduit 74. On the contrary, when the pressure Pl in the liquid container 72 decreases, the flow channel 76 through the valve assembly 74 increases in size or cross-sectional area, thus compensating for the reduced pressure directing the liquid through the flow channel 76. In another preferred embodiment, a second resistor element, output resistor 84, is provided between the set of valves 74 and the outlet 80. The output resistor 84 can protect against peak pressure points passengers (such as those induced when coughing or other increases in abdominal pressure). Those maximum pressure points, in the absence of the output resistor 84, could send backward pressure through the outlet 80, opening the flow channel 76 through the valve assembly 74 and resulting in the possible release of the dosage from bowling or maximum point. An embodiment of a valve assembly 74 is shown in Figure 7. In this embodiment, a linear resistor 82 directs the liquid to a first end of the valve assembly 74 an output resistor 84 directs the liquid out of the outlet 80 and the patient. The valve assembly 74 is preferably located within the pressure element 16 of the infuser 10. The valve assembly 74 can also be positioned outside the pressure element 16 of the fuser 10 in fluid communication with the interior of the inflator 16 pressure element. 10. Figures 8 and 9 illustrate a longitudinal cross-sectional view of the valve assembly 74 in schematic form. Figure 8 illustrates a linear resistor 82 comprising a resistor element 60 covered by an outer casing 66 at the upward end of the valve assembly 74. A flow channel 76 is elongated through the valve assembly 74 to a resistor outlet 84, which also has a resistor element 60 surrounded by an outer envelope 66. The flow channel 76 through the valve assembly 74 is defined by one or more movable walls 86. The movable walls 86 can be formed of any material preferably deformable in the form of a sheet or a fabric, such as polyethylene, Teflon, polyvinyl chloride, polytetrafluoroethylene, polyvinylidine chloride, thin stainless steel and the like. As shown in Figure 9 when an external pressure (indicated by the arrows P) acts on the outside of the movable walls 86, the movable walls are pressed inward to the flow channel 76, squeezing the flow channel 76. From this As the pressure P increases, the cross-sectional area of the flow channel 76 is reduced, thereby reducing the flow of the liquid through the valve assembly 74. It can be appreciated that a great variety of configurations and materials can be used to build mobile walls that will compress the flow channel to the application of mobile wall pressure. Any pressure sensitive valve that uses a moving wall or other pressure sensitive element, such as those in which the flow pressure acts against a spring or the like, are considered to fall within the scope of the present invention. Figures 10-12 illustrate certain convenient embodiments of the valve assembly 74, taken in cross-section to the direction of the flow channel 76. Figure 10 illustrates a simple valve assembly 74, having at least one movable wall 86. against a channel flow 76. In Figure 10, the flow channel 76 is defined by 2 sheets of flexible polymer sealed at their ends 110 by any suitable means, such as heat sealing, solvent welding, RF welding, bending and Clamping with clamps and similar. Figure 11 is an embodiment similar to that illustrated in Figure 10, except that the movable walls 86 or a surface against which the movable wall 86 is placed is provided with minimum flow channels 112, such as longitudinal grooves, protrusions or equivalents, to provide at least one minimum flow channel through the valve 74 despite the pressure exerted against the movable wall 86. The minimum flow channels 112 prevent the movable walls 86 from sticking together under the high outside pressure and reduce the flow channel 76 to a small area that is not very acceptable. The length, height, and width of the flow channels 112 have an effect on the area of the flow channel 76 and can thus be chosen to achieve the desired flow characteristics of the valve assembly 74. A similar arrangement is illustrated in FIG. Figure 12 wherein the opening of the flow channel 76 is maintained by a permanently formed projection 114 between 2 longitudinally extending flow channels 112. The high external pressure would force the movable walls 86 to close together, but the curvature of the interior of the moving wall 86 (or a surface with protrusion against which pressure is applied) would have the tendency to maintain at least one small flow channel 76 open under any normal operating pressure. In addition to the minimum flow channels 112 or projections 114, drip elements 116 can be usefully provided, as illustrated in Figure 12 to keep the flow channel 76 open or to provide a minimum flow channel in the case of a pressure relatively high exterior. In Figure 12 the drip elements 116 are illustrated with a circular cross-sectional area. In other embodiments, the drip elements may have a rectangular cross-sectional area or any other convenient shape. Alternatively, the drip elements may comprise strips of cloth or a cloth or flat material. Similarly as described above, the length and diameter of the drip materials 116 have an effect on the area of the flow channel 76 and thus the desired flow characteristics of the valve assembly 74 can be chosen. of alternative embodiment of a pressure sensitive valve 74 is shown in Figures 23A-B. A sinuous flow channel 76 is created by joining the movable walls 86 to form flow barriers 118. The liquid is restricted to flow around the flow barriers 118 to reach the output resistor 84 and exit the valve assembly 74. Movable walls can be joined using any method of joining thermoplastics such as heat sealing, ultrasonic welding, and solvent bonding. The number and width of the flow barriers 118 determines the degree of reduction of the flow channel 76 by the external pressure acting on the valve assembly 74. Increasing the width or numbers of the flow barriers 118 acts to reduce the flow through the flow channel 76 at the same temperature. The design in Figure 24 shows one more method to create a pressure sensitive valve. The valve assembly 74 of Figure 24 has no linear resistor 82 as shown in Figure 7. Instead an opening 88 is proximally located in one of the movable walls 86 and provides for the fluid inlet to the valve assembly. 74. The output resistor 84 is located distally of the opening 88. The diameter of the opening 88 and the space between the opening 88 and the output resistor 84 has an effect on the amount of liquid exiting from the valve 74. According to FIG. external pressure acting on the valve 74 is reduced, the diameter of the opening 88 increases, the flow through the valve 74 increases. The distance between the opening 88 and the output resistor 84 has an effect on the area of the flow channel 76 and thus can be chosen, achieving the desired flow characteristics of the valve assembly 74. In all the above-described embodiments of the assembly of valves 74, mechanical elements were described to realize the characteristics of the flow channel 76. Furthermore, the material properties of the movable walls 86 can be varied to perform in the degree of compression caused by the external pressure. For example, high durometer polymers compress less and therefore, receive less effect due to pressure changes than low durometer polymers. Thus, a low durometer polymer provides a greater reduction in flow at high pressure by its greater compression of the flow channel 76 and, therefore, provides a higher resistance margin for a given range of pressures than a durometer material high. Figures 17A and 17B illustrate an alternative pressure responsive valve assembly 142 that operates in accordance with the principles just described. Figure 17A is a cross-sectional view of the valve 142 when the pressure in the pressure element 16 is relatively high. The high pressure causes a compressible disk 144 to deform and press against a flow plate 146. The compressible disk 144 can be made of any suitable flexible material such as polystyrene. Varying the physical properties or shape of the discs provides a method to realize the compressibility of the compressible disc 114 and can thus be used to achieve the desired flow characteristics of the valve assembly 74. When the pressure is applied, the compressible disc 144 it provides a partial obstruction of the flow channels 148. The partial obstruction acts as a resistance to flow. In this way, the pressure in each successive valve chamber 150 is lower than in the previous chamber. The number of chambers used depends on the desired flow rate, the pressure range within the pressure element 16 and the patient's bladder, the dimensions of the valve 142 and the dimensions and properties of the material of the compressible disk 144. Figure 17B is a cross-sectional view of the valve 142 when the pressure within the pressure element 16 decreased below that shown in Figure 17A. Note that the compressible disk 144 is no longer pressing the flow plate 146 and the flow resistance through the flow channels 148 has decreased. Figures 18A and 18B illustrate a plus pressure-sensitive valve assembly 152. Figure 18A is a cross-sectional view of the valve 152 when the pressure in the pressure element 16 is relatively high. The high pressure causes a needle 154 to press into the engaged seat 156 thereby deforming a spring 158. In this position, the needle 154 provides a partial obstruction of a flow channel 160 between the needle 154 and the seat 156. The element pressure 16 and needle 154 are separated by a flexible membrane 162, although other embodiments may include an O-ring between needle 154 and seat 156 to prevent fluid in pressure element 16 from entering flow channel 160 A fluid channel 164 provides a path for liquid to flow from inside the pressure element 16 to the flow channel 160. The difference in the pressure at the inlet and outlet of the flow channel 164 determines the degree of channel obstruction. flow 160. Decreasing the pressure within the pressure element 16 decreases the impulse force through the liquid channel 164. Figure 18B is a cross-sectional view of the valve 152 when the pressure within the pressure element 16 decreased below that shown in Figure 18A. Note that spring 158 presses needle 154 into flexible membrane 162 and away from seat 156, decreasing the flow resistance through the channel 160. The embodiments of the infuser illustrated in Figures 2 and 3 include an extensible fabric member 34 within the pressurized interior 16. However, it should be appreciated that the term extensible elements is interprets broadly in the present invention. Multiple embodiments of the extensible element are illustrated in Figures 13A-13B. Figure 13A is a cross-sectional view of the pressure element 16 in the infuser 10 having a thin side 120 and a thick side 122. Because the thick wall 122 is less extensible than the thin wall 120, the infuser 10 will take a shape arched, curved or circular at the time of inflation. Note that the thick wall 122 may be a gradual thickening of the device, or alternatively, it may be a protrusion or strip of thickened material. If the thick wall 122 extends along the same side of the pressure element 16 over its entire length, the two ends 12, 14 of the infuser 10 will bend towards each other. Alternatively, if the thick wall 122 spirals around the pressure element 16 along its length, the infuser will have a tendency to assume a helical or spiral structure. Alternating the place of the thick wall 122 from side to side can form any number of potential geometric shapes. Figure 13B illustrates an embodiment where the extendable member 34 is within the pressing member 16; the extendable member 34 can be formed of any inextensible material, including cable, cloth or polymer. We have discovered that a polyester ribbon has useful properties. Figure 13C illustrates an embodiment where the extendable element 34 is located on or on or in the wall of the pressure element 16. The extendable element 34 may be completely embedded, partially embedded, or adhered to the inner wall or outer wall of pressure element 16. This can be carried out by coextruding the element of the extensible element 34 with the pressing element 16, or by subsequent welding or adhesive bonding to the pressing element 16. In still another embodiment, as illustrated in Figure 13D, the expandable element 34 is located externally to the pressure element 16 as illustrated in Figure 13D. In this embodiment, the pressure element 16 assumes a curved or arched shape, while the extensible element forms a straight line between the two ends 12, 14 of the infuser 10. This embodiment has the advantage of reducing the risk of premature emptying of the infuser 10 even if one of the ends 12, 14 approaches the urethra, and also provides a point of suggestion for subsequent removal of the infuser 10, taking the place of the capture loop 36. Figure 13E illustrates a form of embodiment wherein the extensible element 34 comprises a material different from the rest of the pressure element 16. The extensible element 34, for example, can be a relatively inextensible material compared to the rest of the pressure element 16. This can be welded or joined to the pressure element 16, or, preferably, can receive coextrusion with the material forming the pressure element 16. If silicone is used for the pressure element 16, by axis mplo, a less extensible and more highly crosslinked silicone can be co-extruded with the rest of the pressure element 16, forming a part of the wall of the pressure element 16. Alternatively, it is possible to use a material that is more extensible than the rest of the element of pressure 16, in which case the coextruded material will elongate more than the rest of the pressure element and the curvature will move away from the coextruded material. It should be recognized that there are several equivalent methods for deforming an infuser after implantation. The present invention should not be interpreted so literally that other shape-shifting techniques are avoided. Figure 14 is a schematic representation of an alternative form change technique. In this embodiment, an expandable element 34 is connected to the proximal and distal ends of the infuser 10. The extensible element can be shortened axially, with respect to the fuser 10 as illustrated in Figure 15. In the illustrated embodiment, a ratchet mechanism 124 allows that the expandable element 34 is extracted from an opening in the infuser 10 and held in that short position. A final coil shape is illustrated in Figure 15. However depending on the geometry of the infuser 10 and the location of the expandable element inside or outside of the infuser 10, the latter shape may be circular, supercoidal, arched, or any of several other configurations convenient. The method of the present invention is further illustrated in Figures 16A-16E. In Figure 16A the mfuser 10 is inserted into the bladder 130 of the patient through the urethra 132 using an outer wrap 66, and an expander 70. A hypodermic needle 38 is inserted through the outer wrap 66 and the expander 70 in the septum 42 of the fuser 10. Figure 16B illustrates the filling of the infuser 10 through a cannula or other liquid transmission device within the expander 70. Note that the infuser 10 assumes an arcuate or circular shape at the time of filling.

After the filling is complete, the needle 38 is removed, allowing the infuser 10 to freely float within the bladder 130, as illustrated in Figure 16E. Alternatively, the infuser 10 can be attached to the bladder wall using any of a variety of conventional fastening means, including sutures, staples and adhesives. The installation and removal of fasteners can be carried out in a number of ways, including cystoscopy. To help easily remove the device, dissolvable sutures can also be used. In addition, a layer of pentasanpolisulfate can be applied to the fastener, especially when using non-dissolvable elements, such as non-dissolvable suture. Additional information regarding the coating of pentasanpolysulfate can be found in U.S. Patent Application Serial No. 08 / 942,972 filed on October 3, 1997 entitled "PENTOSANPOLYSULFATE COATING FOR MEDICAL DEVICES" which is "PENTOSANPOLISULFATE COATING FOR MEDICAL DEVICES". a follow-up file of a United States patent application serial number 08 / 642,391, the disclosure of which is included herein for reference. After the substance or drug has been poured, infuser 10 can be refilled for additional intravesical delivery of drug or can be removed from the patient and replaced by another infuser 10 as needed. The filling can be carried out in a manner similar to filling. The capture loop 36 or other capture arrangements can be used to manipulate the infuser 10 within the bladder 130 during filling. Figure 16D illustrates a technique for removing the infuser after the drug was poured or the treatment has finished its course. A cystoscope 134 and a scalpel, needle or other tear or cut tool 136 that is used to puncture or tear the infuser 10 is inserted into the bladder 130 of the patient, thereby releasing the internal pressure and allowing the infuser to deflate. to a not full state. If desired, the rest of the farmed within the bladder can be removed or withdrawn if release of a substantial amount of the drug is not well tolerated. Alternatively, the infuser can be emptied by activating a release mechanism that allows a low resistance flow through the valve assembly in order to deflate to an unfilled state before removing infuser 10 from the patient. In a preferred embodiment, the drug is withdrawn from the infuser through a conduit (such as a needle 38 and any attached tube) directly out of the bladder, so that the release of a bolus dose of drug in the bladder is prevented. Bladder 130 Figure 16E illustrates the removal of infuser 10 from the patient's bladder 130. Cystoscope 134 is used to introduce a recovery tool 140 of any convenient design. The retrieval tool 140 grips or holds the capture loop 36 allowing the deflated infuser 10 to be removed from the bladder 130 via the urethra 132. In other embodiments, the retrieval tool may include fasteners, hooks, clamps, magnets, adhesives or any other type of design that allows the subjection and recovery of the infuser. The method of the present invention is further illustrated in Figures 25A-25D together with the infuser 10 illustrated in Figure 19. In Figure 25A the infuser 10 is inserted into the patient's bladder 130 through the urethra 132 using an introducer . After the transurethral introduction of the outer sheath 266 of the introducer into the bladder, the deflated infuser 10 passes through the outer sheath 266 to the position illustrated in Figure 25A. The secure coupling attachment 260 fits exactly to the opening 230 of the infuser 10. In this position, the liquid drug flows through the introducer channel 264 located within the expander 262 of the introducer. The liquid flows from the introducer channel 264 through the inlet of the valve 246 into the liquid chamber 250 and fills or inflates the infuser 10.

When the filling is complete, secure attachment attachment 260 is disconnected from infuser 10 as shown in Figure 25B to float freely in the patient's bladder. The expander 262 retracts into the outer wrap 266 and both are removed from the patient. Figure 25C illustrates a technique for removal of the infuser after the drug was poured or the treatment has ended. A recovery device 270 is inserted into the bladder 130 of the patient. The capture element 276 extends from the recovery channel 274. The capture element 276 is coupled to the capture element 236. The capture element 276 is retracted in the shell 272. In Figure 25D, the end cap stop distal 228 sits accurately against the entrance of channel 278. The remainder of the fluid within infuser 10 is flowing from inside infuser 10 through recovery channel 274 and out of the bladder so as to prevent the release of a bolus dose of drug in the bladder 130. Of course, it will be appreciated that the illustrated embodiments represent only one preferred method for practicing the invention. Numerous minor variations are possible without departing from the spirit of the invention. For example, in lieu of a septum needle and valve arrangement, any number of various valve mechanisms and clamping mechanisms can be used to connect the fuser 10 to the expander 70 or the hypodermic needle 38 (or a cannula or fastener that take the place of the hypodermic needle 38). Thereby, the outer source of fluid can be attached to the interior of the pressure element 16 by means of a valve mechanism, and the infuser 10 can be physically joined and detached from the expander 70. In addition to the use of a capture loop 36, numerous other capture arrangements are possible. For example, a capture mechanism can be used to pull one end of infuser 10 to a proximity sufficiently close to cystoscope 134 so that capture can be performed. In the same way you can use a basket or a mesh of expansion and contraction ("Chinese finger trap"). In other embodiments of the invention, the collars 24, 26 or other portions of the infuser can be made radiopaque in order to facilitate viewing of the mfusor by ultrasound, X-rays or other display means. In one embodiment of the invention, a mechanically driven, electrically driven, or osmotically driven infusion element is replaced by the pressure element 16. Alternatively the substance or drug used in the invention can be impregnated in a release material. controlled or biodegradable that carries out a change of form at the time of introduction to the bladder. In an important aspect of the invention, all the mfuser 10 or appropriate portions thereof can be coated with a biocompatible coating. A major problem that has been experienced with most devices that are left in the bladder for more than a few days is embedding or infection. Several salts, proteins and other materials in the urine can quickly accumulate in foreign objects that are left inside the bladder. This, in turn, leads to irritation and difficulty in removing the device without injuring the patient. In some cases, all of the infuser 10 can be coated. In other cases, only appropriate portions of the infuser 10 are coated such as the proximal end cap 20 and the distal end cap 22. We have discovered that certain coatings of polysaccharides can reduce or even prevent scaling. These coatings include pentosanpolysulfate, heparin and other sulfonated polysaccharides or drugs. Silicone and many biocompatible plastics will not readily accept a coating of these biocompatible materials. We have discovered that this obstacle can be overcome by pretreating the surface of the device by means of any number of surface modification techniques. These include corona discharge, ionic discharge, chemical attack such as by means of a treatment with a strong base and plasma treatment. One technique is disclosed in the aforementioned United States patent application serial number 08 / 942,972 filed on October 3, 1997, entitled "PENTASANPOLYSULFATE COATING FOR MEDICAL DEVICES." (PENTASANPOLISULFATE COATING FOR MEDICAL DEVICES). An infuser according to the invention can be used as a means of self-containment to deliver therapeutic agents to a variety of functioning organs within a living organism. The infuser can be introduced to the functioning organ through a natural orifice or a created hole. In one embodiment, the device is located within the bladder, is filled with a reconstitution agent that causes a change of shape in the device and activates the agent within the device. For example, the device can be filled with a saline solution that activates a powerful drug within the device. In methods for using the device that fall within the scope of the present invention, a wide variety of drugs or other substances, including contrast agents, can be administered to the bladder. These drugs or other substances can be provided in a variety of ways tessh * aSs including liquids and powders with hydration capacity. These drugs and other materials can be used for a variety of purposes, including the treatment of urinary incontinence, cancer in the urinary tract, urinary tract infections, inflammatory conditions of the urinary tract, and to provide pain relief. Urinary incontinence, which includes urge incontinence and neurogenic incontinence, can be treated using the device of the present invention. Preferably anticholinergic and / or antispasmodic agents are used. In addition, antimuscarinic agents, B-2 agonists, norepinephrine absorption inhibitors, serotonin absorption inhibitors, calcium channel blockers, potassium channel openers and muscle relaxants can also be used. Suitable drugs for the treatment of incontinence include oxybutynin, S-oxybutynin, emepronium, verapamil, imipramine, flavoxate, atropine, propantheline, tolterodine, rociverin, clenbuterol, darifenacin (Pfizer, Europe, USA, Japan), terodiline, trospium, hyoscyamine, propiverine, desmopressin, vamicamide (Fuj iwara Co. Japan), YM-46303 (Yamanouchi Co., Japan), lamperisone (Nippon Kayaki Co., Japan), inaperisone, NS-21 (Nippon Shinyaki Orion, Formenti, Japan / Italy), NC-1800 (Nippon Chemiphar Co., Japan), ZD-6169 (Zeneca Co., United Kingdom), and estimonio iodide. In addition, the substance released from the device can be used for diagnostic purposes. Urinary tract cancer, such as bladder cancer and prostate cancer, can be treated using the device of the present invention by flushing antiproliferative agents, cytotoxic and / or chemotherapeutic agents. Suitable drugs for the treatment of cancer in the urinary tract include Bacillus Calmette Guerin (BCG) vaccine, cisplatin, doxorubicin, methotrexate, vinblastine, thiotepa, mitomycin, fluorouracil, leuprolide, flutamide, diethylstibestrol, estramustine, megestrol acetate, cyproterone, flutamide and cyclophosphamide. The treatment of cancer in the urinary tract can also be carried out along with other conventional cancer treatment techniques, including surgical removal and radiation therapy. Similarly infections that include the bladder, prostate and urethra can be treated using the device of the present invention. Antibiotics, antibacterials, antifungals, antiprotectives, anti-virus and other anti-infective agents can be administered to treat such infections. Suitable drugs for the treatment of these infections include mitomycin, ciprofloxacin, norfloxacin, ofloxacin, methanamine, nitrofuranton, ampicillin, amoxilin, nafcillin, trimethoprim, sulfa, trimethoprim-sulfamethoxazole, erythromycin, doxycycline, metronidazole, tretacycline, kanamici, penicillins, cephalosporins and aminoglycosides. Inflammation conditions such as interstitial cystitis, prostatitis, urethritis can also receive treatments using the device of the present invention. Drugs that have an anti-inflammatory and / or coating effect are useful with respect to this issue. Suitable drugs include dimethyl sulfoxide (DMSO), heparin, sodium pentasanpolysulfate, and flavoxate. The device of the present invention can also be used to provide pain relief in the patient. In this regard, a variety of anesthetic and / or analgesic agents can be flushed through the device of the present invention, including lidocaine hydrochloride, procaine hydrochloride, salicylic alcohol, tetracame hydrochloride, phenazopyridine hydrochloride, acetaminifene, acetylsalicylic acid, , flufenisal, ibuprofen, indoprofen, indometacm, naproxen, codeine, oxycodone, and fentanyl citrate. The device of the present invention can also be used to administer drugs and other materials for a variety of other purposes. For example, the device can be used to administer glycine for purposes such as irrigation of the bladder.

The method of treatment of the present invention provides slow, continuous, intermittent or periodic release of a desired amount of drug for a desired period of time. In a preferred embodiment, the infuser volume is such that it can deliver the desired dose of drug for a period of time, for example, 24 hours 5 days, 10 days, 15 days, or even 20, 25, 30, 60, 90 days or more. The speed of delivery in order to carry out this result is relatively slow. Thus, the present invention contemplates drug delivery rates within the range of 0.1, 1, 5, 10, 25, 50, 75, 100, 150, 200 or 400 nl / hr. Of course, the fastest or slowest delivery speeds can be selected depending on the drug being delivered and the disease being treated. In any particular situation, and for any particular disease state, the concentration of the drug and the delivery rate can be selected by the physician based on conventional methodologies. The infuser device of the present invention has been successfully tested in adult pigs. The practice of the present invention is illustrated in the following examples which have no limits. EXAMPLE 1 Female pigs with a weight range of 40-45 kg. were sedated using 10 ml. Of ketamine chloride and 3m. of atropine. Upon achieving the correct sedation, an endotrachial tube was placed in the animal's canal and the animal was maintained with isoflurane gas between 0.5% and 4% as intraoperative anesthesia. Following the standard sterilization procedures, a 21 Fr Storz cystoscope was used to visualize and place a 0.038 inch guidewire in the pig's bladder. Removing the cystoscope, a 23 Fr introducer sheath and obturator were passed over the guidewire to the bladder of the animal. The obturator and the guidewire were removed. An infuser mounted on a 23 gauge needle at the distal end of a launcher tube was placed through the introducer sheath into the bladder. A 60 cc syringe installed in an infusion aid device was attached to the proximal end of the launcher tube through the tube section. The tube was purged before carrying out the joint to remove all the air from the system. The 60 cc syringe was filled with 35 cc of a tritium-labeled pentosanpolysulphate sodium drug. Total radioactivity counts of the tritium-labeled drug for the 35 cs were measured from a 100 ml sample of drug using a Beckman scintillation counter to begin the study. The mfusor was placed in the bladder so that most of the infuser was extended beyond the introducer sheath. 30 cc of drug was injected into the infuser and the infusor was . S and expanded to the filling state. The 23 gauge needle was removed from the infuser and the sheath of the introducer and the launcher were removed from the patient, allowing the infuser to float freely within the bladder. The pigs were allowed to recover from the anesthesia and returned to their cells. The total urine production of the pigs was collected and measured daily for 30 days. The total urine output varied between 1.75-3.5 liters / day. A 100 ml sample was taken from each daily collection and placed in a Beckman scintillation counter to determine the number of radioactive counts within the sample. The measurement gave the total of counts in the daily collection that was compared to the original measurement of the total counts made at the beginning of the study to determine the amount of drug in the daily collection. The average counts of a 100 ml sample of a daily collection typically measured 750-1000 counts. In this way, it was determined that the production of the device varied between 2 ce per day at the beginning of the study to 0.75 ce on the thirtieth day of the study. At the end of 30 days, the animal was sacrificed by means of a 12 ml injection of Beutanasia-D and if bladder was removed. Histological specimens were taken from the areas of the neck, trine, base and dome of the bladder, fixed formaldehyde, embedded in paraffin, sectioned and painted with H &E; The examination of the sections showed normal tissue without apparent lesion caused by the mfusor.

EXAMPLE 2 The infusor can be used in human patients to treat neurogenic bladder diseases or urge incontinence using anticolinergic or antimuscarinic drugs such as oxybutynin or flavoxate. One patient was prepared in the dorsal lithotomy position. Standard cystoscopic procedures were performed on the patient using local anesthesia and with accepted sterilization techniques. An introducer sheath and transurethral obturator were placed to allow access to the bladder. To minimize patient discomfort, water-soluble lidocaine gel was used to facilitate the passage of the introducer-obturator envelope into the urethra. The obturator was removed and the infuser passed through the introducer to the bladder. The infuser was connected to a source of therapeutic agent through the envelope of the introducer. The infuser was filled with approximately 30 cc of the therapeutic agent from the source. The source of therapeutic agent may comprise a hypodermic needle penetrating a hedge into the infuser or pressure sources opening a unidirectional valve in the infuser.

After the filling is complete, the source is disconnected from the infuser so that the infuser floats freely within the bladder. The introducer is removed from the urethra. The infuser remains in the patient's bladder for 30 days by flushing out therapeutic agent to alleviate the symptoms of urge incontinence or neurogenic bladder disease without side effects associated with alternate drug administration routes such as oral or intravenous methods. After 30 days the patient is prepared in a manner similar to that described above. A cystoscope is inserted through the urethra into the bladder and the mfusor is located by visualization. Any residual therapeutic agent remaining in the infuser is removed to reduce the profile of the infusor and facilitate its removal. Removal of the therapeutic agent can be carried out by passing a needle or a cutting tool through the working channel of the cystoscope to tear the infuser. Alternatively, a tool for accessing the release mechanism in the infuser can drain the contents of the infuser. The bladder can be sprayed in order to remove the released drug if necessary. A recovery tool passes through the working channel of the cystoscope. The recovery tool holds the infuser and removes it from the bladder. The infuser and cystoscope are removed from the urethra. A subsequent infusor can be inserted into the bladder following the procedure described above if additional therapy is necessary. Although this invention has been described of certain preferred embodiments, other embodiments that will be apparent to those skilled in the art in view of the disclosure herein are also within the scope of this invention. Accordingly, the scope of the invention will be defined by reference in the appended claims.

Claims (109)

1. Claims 1. An implantable intravesical infusion device, comprising: a container having a first shape which allows the container to be deposited in a body cavity, the container being configured to stretch to a second shape and retain a pressurized substance; a valve assembly configured to admit the liquid substance pressurized into the container while the container is within the body cavity; and an outlet orifice with restricted flow configured to distribute the pressurized substance from the container while it is within the body cavity. The device of Claim 1, further comprising a fastening element for attaching the device to the wall of the body cavity. The device of Claim 1, wherein the first form is a linear configuration with at least one axis of symmetry and wherein the second form has a curved configuration that has no axial symmetry. 4. The device of Claim 1, wherein the container substantially retakes the first form as the pressurized substance is distributed. 5. The device of Claim 1, wherein the container is coated to inhibit the container of materials present in the urinary tract. The device of Claim 1, wherein the container is coated to increase the lubricity of the device. The device of Claim 1, wherein the outlet orifice with restricted flow provides a means for rapidly draining the pressurized substance from the container. 8. The device of Claim 1, wherein the container substantially retakes the first form at the time the pressurized substance is drained. 9. The device of Claim 1, wherein the container is elongated, the valve assembly is positioned at a first end of the elongated container and the restricted flow exit orifice is placed at a second end of the elongated container opposite the first end. The device of Claim 9, wherein the second end can float more than the elongate container. 11. The device of Claim 9, wherein the second end is at least partially covered by an adaptive stop. 12. The device of Claim 9, further comprising a capture element. 13. The device of Claim 9, further comprising a capture element exiting from the center of the second end. The device of Claim 12, wherein the capture element is incorporated in a release mechanism that is configured to allow the exit orifice with restricted flow to drain the pressurized substance from the elongate container. 15. The device of Claim 1, further comprising a capture element attached to the exit orifice with restricted flow, wherein if force is exerted on the capture element while maintaining counter pressure in the flow exit orifice. restricted, this restricted flow from the outlet orifice is reduced so that the pressurized liquid substance is drained. 16. The device of Claim 16 (15?), Wherein the outlet orifice with restricted flow is configured to enter a shell that is introduced into the body cavity so that the pressurized substance is drained through a channel. of the envelope instead of the body cavity. 17. The device of Claim 1, wherein the exit orifice with restricted flow provides the deposit of the pressurized substance for a period of time of at least 5 days. 18. The device of Claim 1, wherein the exit orifice with restricted flow provides delivery of the pressurized substance for a period of at least 15 days. 19. The device of Claim 1, wherein the pressurized substance has a liquid form and the device delivers the pressurized liquid substance at a rate of less than about 400 μl / hour. 20. The device of Claim 1, wherein the second form facilitates the retention of the elongated container in the body cavity. The device of Claim 1, wherein the second form is transverse with sufficient diameter to prevent the elongate container from passing through a mammalian urethra. 22. The device of Claim 1, wherein the second form prevents obstruction of a mammalian bladder neck to allow urine to pass around the device. 23. The device of Claim 1, wherein the second form is curved. 24. The device of Claim 23, wherein the container is elastomeric. [* > * 25. The device of Claim 1, wherein the pressurized substance is a drug. 26. The device of Claim 1, wherein the pressurized substance is a diagnostic tool. 27. The device of Claim 1, wherein the container is elongated and a first end thereof floats more than the container. The device of Claim 27, wherein the buoyancy of the first end causes the device to float with the first end placed on top of the elongate container. 29. The device of Claim 1, wherein the first end is at least partially covered by an adaptive stop. 30. The device of Claim 1, wherein the valve assembly comprises an opening for accepting a secure coupling fitting through which the pressurized substance is distributed. The device of Claim 30, wherein the opening is also for securing the device to an introducer that is used to place the device within the body cavity. 32. The device of Claim 1, wherein the valve assembly comprises a floating disk that deflects to obstruct an inlet channel. The device of Claim 1, wherein an outlet orifice with restricted flow resistance varies in proportion to a pressure level of the pressurized substance so that the outlet orifice with restricted flow distributes the pressurized liquid substance at a rate controlled 34. The device of Claim 33, wherein the exit orifice with restricted flow varies the resistance by varying an area of a flow channel of the exit orifice with restricted flow in inverse proportion to the pressure level of the pressurized liquid substance. 35. The device of Claim 1, wherein the outlet orifice with restricted flow comprises a first pressure reducing element, a second pressure reducing element and a flow channel through the first and second pressure reducing elements, in where the second pressure reducing element alters a transverse area of the exit orifice with restricted flow in a manner inversely related to a pressure level of the pressurized substance. 36. The device of Claim 1, wherein the exit orifice with restricted flow is made of sintered metal. 37. An intravesical infusion device comprising: a pressure element containing a drug; an exit orifice with restricted flow in fluid communication with the drug of the pressure element; and a liner of the device adapted to provide lubricity or inhibit the deposit of material in the device when placed in a body cavity of a mammal. 38. The device of Claim 37, wherein the coating inhibits the deposit of materials present in the urinary tract. 39. The device of Claim 37, wherein the coating is superficial on surfaces of the device exposed to the body at implantation. 40. The device of Claim 37, wherein the coating is impregnated in the device. 41. The device of Claim 37, wherein the liner covers only a portion of the device. 42. The device of Claim 37, wherein the exit orifice with restricted flow provides delivery of the drug for a period of at least 5 days. 43. The device of Claim 42, wherein the exit orifice with restricted flow provides delivery of the drug for a period of at least 15 days. 44. The device of Claim 42, wherein the drug is in liquid form and the device delivers the drug at a rate of less than about 400 μl / hour. 45. The device of Claim 37, wherein the device takes a first form during implantation and a second form after implantation in a mammal. 46. The device of Claim 45, where the device takes the first form when it is emptied and the second form when it is filled. 47. The device of Claim 46, wherein the first form is generally elongated and the second form is curved. 48. The device of Claim 45, wherein the pressure element is elastomeric. 49. The device of Claim 37, wherein the drug is for treating incontinence. 50. The device of Claim 37, wherein the drug is used to treat urge incontinence. 51. The device of Claim 37, in ~ "* • where the drug is an anesthetic or analgesic. 52. The device of Claim 37, wherein the drug is an antibiotic. 53. The device of Claim 37, wherein the drug is used to treat cystitis. 54. The device of Claim 37, wherein the drug is for fighting cancer. 55. The device of Claim 37, wherein the drug is oxybutynin. 56. The device of Claim 37, wherein the device has a first end and a second end, wherein at least one of the ends is floating. 57. The device of Claim 56, wherein the first end and the second end are floating. 58. The device of Claim 37, wherein the device is sized to fit through an urethra in a mammalian bladder. 59. An intravesical infusion device comprising: an elongate element of elastomeric pressure adapted to contain and pressurize a liquid, the elastomeric pressure element having a first end and a second end; a flow controller that provides an outlet orifice in fluid communication with the liquid in the elastomeric pressure element, the flow controller provides controlled release of the liquid from the device; and an expandable element coupled to the elastomeric pressure element adjacent the first end adjacent the second end so as to allow a relatively straight configuration of the device when it is not filled with liquid and to specify a curved configuration of the device when filled with liquid. 60. The device of Claim 59, wherein the extensible element is within the elastomeric pressure element. 61. The device of Claim 59, wherein the elastomeric pressure element includes a wall and the extensible element is associated with the wall. 62. The device of Claim 59, wherein the expandable element forms a part of the wall. 63. The device of Claim 59, wherein the expandable element is outside the elastomeric pressure element. 64. The device of Claim 59, further comprising an incrustation-resistant coating on the device. 65. The device of Claim 59, further comprising a floating portion at the first end. 66. The device of Claim 65, further comprising a floating portion at the second end. 67. A system for implanting a mtravesical infusion device comprising: an intravesical infusion device having an internal chamber, the intravesical infusion device adapted to change shape when the internal chamber is filled; an introducer that removably holds the infusion device, the introducer is suitable for inserting a patient's body cavity in vivo; and a conduit associated with the introducer removably coupled to the infusion device and in fluid communication with the internal chamber to fill the infusion device in vivo. 68. The system of Claim 67, wherein the conduit is inside the introducer. 69. The system of Claim 67, wherein the conduit is attached to a removable valve in the infusion device. 70. The system of Claim 69, wherein the detachable valve is a separator seal and the conduit includes a needle for piercing the separator seal. 71. The system of Claim 69, wherein the detachable valve comprises a secure coupling female fitting coupled to a unidirectional valve wherein the conduit contains a secure coupling male fitting adapted to mate with the first female accessory. 72. The system of Claim 67, further comprising an expander located within the introducer adapted to push the infusion device distally from the introducer. 73. A method for delivering a drug to a patient, comprising the steps for: delivering an infusion device in a patient's bladder; release the infusion device in the bladder to move freely in it; and pouring a drug into the bladder from the infusion device. 74. The method of claim 73, further comprising the step for securing the device to the wall of the bladder. 75. The method of claim 73, wherein the infusion step comprises pressurizing the drug with an elastomeric element and releasing the drug at a controlled rate from the infusion device. 76. The method of claim 75, further comprising the step for filling the infusion device with the drug while the device is in the bladder. 77. The method of claim 75, further comprising the step for filling the infusion device with a reconstitution agent that activates the drug while the device is in the bladder. 78. The method of claim 75, wherein the drug is present in condensed form in the infusion device during the step of depositing the infusion device in the patient. 79. The method of claim 76, wherein the filling step induces the infusion device to change shape. 80. The method of claim 79, wherein the shape change comprises a change in profile. 81. The method of claim 79, wherein the shape change is from a straight configuration when empty to a curved configuration when full. 82. The method of claim 79, wherein the shape change is of a linear configuration with at least one axis of symmetry when empty to a curved configuration that does not have axial symmetry when full. 83. The method of claim 73, wherein the infusion step comprises pouring the drug into the bladder for at least 24 hours. 84. The method of claim 73, wherein the infusion step comprises pouring the drug into the bladder for at least about 5 days. 85. The method of claim 73, wherein the delivery step comprises inserting the infusion device through the urethra into the bladder in an unfilled state within an introducer, then releasing the infusion device from the introducer into the bladder. . 86. The method of claim 73, wherein the delivery step comprises stretching at least a portion of the infusion device from the introducer, and then filling the device into the bladder. 87. The method of claim 73, wherein the drug is for treating incontinence. 88. The method of claim 73, wherein the drug is used to treat urge incontinence. 89. The method of claim 73, wherein the drug is oxybutynin. 90. The method of claim 89, wherein the oxybutyn is released at a controlled rate in the bladder for a period exceeding 24 hours. 91. The method of claim 73, wherein the drug is used to treat pain or neuralgia. 92. The method of claim 73, wherein the drug is an antibiotic. 93. The method of claim 73, wherein the drug is used to treat cystitis. 94. The method of claim 73, wherein the drug combats cancer. 95. The method of claim 73, further comprising the step of removing the infusion device from the bladder after the infusion step. 96. The method of claim 73, wherein the infusion device takes a first form when it is empty and a second form when it is full, and wherein the removal step comprises changing the shape of the infusion device of the second form to the first form and then direct the infusion device out of the urethra. 97. The method of claim 96, wherein the change from the second form to the first form is carried out by allowing matter within the device to be emptied by means of the infusion step. 98. The method of claim 96, wherein the change from the second form to the first form is carried out by opening a passage in the device to allow matter within the device to exit therefrom. 99. The method of claim 98, further comprising the step of directing the drug from the passage through the conduit and out of the bladder. 100. The method of claim 96, wherein the removal step comprises removing the device from the urethra with a flow of urine. 101. The method of claim 96, wherein the removal step comprises capturing and then removing the device. 102. The method of claim 73, wherein the infusion step comprises controlling the flow rate of the drug from the device to the bladder. 103. The method of claim 102, further comprising controlling the flow of drug by means of a pressure sensitive valve. 104. The method of claim 103, wherein the drug is under pressure and the pressure sensitive valve controls the flow by varying the area of a flow channel in inverse proportion to the drug pressure. 105. The method of claim 104, wherein the flow control is further carried out by a flow resistance element placed in an upward stream of liquid flow path of the pressure sensitive valve, thereby reducing the pressure of the drug that enters the pressure-sensitive valve. 106. An intravesical infuser comprising: a pressure element; a drug within the pressure element; a flow controller coupled to the pressure element to control the rate at which the drug is released from the pressure element; and a coating on the device adapted to provide lubricity or to inhibit deposition of material in the device when implanted within a body cavity of a mammal. 107. The device of Claim 106, where the drug is pressurized and the flow controller is sensitive to pressure. 108. The device of Claim 106, wherein the flow controller comprises a first pressure reducing element, a second pressure reducing element and a channel through the first and second pressure reducing elements, wherein the second reducing element. of pressure alters a cross-sectional area of the flow path in inverse manner relative to the pressure of the drug. 109. The device of Claim 106, wherein the flow controller further comprises a third pressure reducing member downstream of the first and second pressure reducing elements.