Implantable device for controlled drug delivery

Abstract

Implantable devices and methods for delivery of lidocaine or other drugs to a patient are provided. In one embodiment, the device includes a first drug portion which has a first drug housing which contains a first drug formulation in a solid form which includes a pharmaceutically acceptable salt of lidocaine; and a second drug portion which includes a second drug housing which contains a second drug formulation which includes lidocaine base. In another embodiment, the device includes a drug reservoir component which has an elastic tube having at least one lumen bounded by a porous sidewall having an open-cell structure, a closed-cell structure, or a combination thereof; and a drug formulation contained within the at least one lumen, wherein the device is deformable between a low-profile deployment shape and a relatively expanded retention shape.

We claim: 
     
         1 . An implantable device for delivery of lidocaine to a patient, comprising:
 a first drug portion which comprises a first drug housing which contains a first drug formulation which comprises a pharmaceutically acceptable salt of lidocaine, the first drug formulation being in solid form; and   a second drug portion which comprises a second drug housing which contains a second drug formulation which comprises lidocaine base.   
     
     
         2 . The device of  claim 1 , wherein the first drug housing is water permeable, impermeable to the lidocaine salt, comprises an aperture, and provides release of the lidocaine salt in vivo by osmotic pressure. 
     
     
         3 . The device of  claim 1 , wherein the second drug housing is permeable to water and to lidocaine base in aqueous solution, and provides release of the lidocaine base in vivo by diffusion. 
     
     
         4 . The device of  claim 1 , wherein the first and second drug housings are partitioned areas of a single tubular body. 
     
     
         5 . The device of  claim 4 , wherein at least one of the first and second drug formulations comprises a plurality of drug tablets aligned within the single tubular body in a row. 
     
     
         6 . The device of  claim 5 , wherein the single tubular body is formed from silicone. 
     
     
         7 . The device of  claim 1 , wherein the first and second drug portions are operably associated with a retention portion. 
     
     
         8 . The device of  claim 7 , wherein the retention portion comprises a retention frame. 
     
     
         9 . The device of  claim 7 , wherein the device is deformable between a retention shape and a deployment shape. 
     
     
         10 . An implantable device for delivery of lidocaine into the bladder of a patient, comprising:
 a first drug portion which comprises a first drug housing which contains a first drug formulation which comprises lidocaine hydrochloride, the first drug formulation being in solid form;   a second drug portion which comprises a second drug housing which contains a second drug formulation which comprises lidocaine base; and   a retention frame with which the first and second drug portions are operably associated,   wherein the device is deformable between a deployment shape permitting deployment of the device through the patient's urethra and a retention shape for retaining the deployed device within the bladder.   
     
     
         11 . An implantable medical device for controlled drug delivery device comprising:
 a drug reservoir component which comprises an elastic tube having at least one lumen bounded by a porous sidewall having an open-cell structure, a closed-cell structure, or a combination thereof; and   a drug formulation contained within the at least one lumen,   wherein the device is deformable between a low-profile deployment shape and a relatively expanded retention shape.   
     
     
         12 . The device of  claim 11 , wherein the drug formulation is in a solid or semi-solid form when contained in the lumen and becomes solubilized in vivo for release. 
     
     
         13 . The device of  claim 11 , wherein the porous sidewall comprises silicone. 
     
     
         14 . The device of  claim 11 , wherein the porous sidewall further comprises one or more punched or machined apertures. 
     
     
         15 . A method of delivering lidocaine into a patient's bladder, comprising:
 deploying into the patient's bladder a device which comprises a water permeable housing which contains lidocaine base in solid form; and   following solubilization of the lidocaine base in vivo, releasing from the device the solubilized lidocaine into the bladder through the water permeable housing.   
     
     
         16 . The method of  claim 15 , wherein the device further includes a pharmaceutically acceptable salt form of lidocaine, which is also released from the device following solubilization of the lidocaine salt in vivo. 
     
     
         17 . The method of  claim 15 , wherein a therapeutically effective amount of lidocaine is released over an extended period by a combination of diffusion and osmotic pumping. 
     
     
         18 . The method of  claim 15 , wherein the solid form of the lidocaine base comprises a plurality of tablets, and the water permeable housing comprises a silicone tube. 
     
     
         19 . The method of  claim 18 , wherein the silicone tube is closed at its ends and has no aperture.