Osmotic delivery system, osmotic delivery system semipermeable body assembly, and method for controlling delivery rate of beneficial agents from osmotic delivery systems

Abstract

Osmotic delivery system semipermeable body assemblies that control the delivery rate of a beneficial agent from an osmotic delivery system incorporating one of the semipermeable body assemblies are provided. A semipermeable body assembly or plug includes a semipermeable body which is positionable in an opening of an osmotic delivery system. The semipermeable body has a hollow interior portion having a size selected to obtain a predetermined liquid permeation rate through the semipermeable body. Because the beneficial agent in the osmotic delivery system is delivered at substantially the same rate, the osmotic agent imbibes liquid which has permeated through the plug from a surrounding environment, and the liquid permeation rate through the plug controls the delivery rate of the beneficial agent from the osmotic delivery system. The liquid permeation rate through a semipermeable body may be varied to control the delivery rate of beneficial agent from an osmotic delivery system by changing the thickness of the semipermeable body or by changing an amount of surface area of the semipermeable body that is exposed to liquid when the osmotic delivery system is located in a liquid environment of use.

1 . An osmotic delivery system plug for controlling a delivery rate of a beneficial agent in an osmotic delivery system, the plug comprising: 
 a semipermeable body having:    a recess having an interior surface beginning at an opening in the body and ending at a depth surface within the semipermeable body;    a liquid contact surface located opposite the depth surface;    an outer surface located opposite the interior surface, the outer surface having means for sealing an environment of use from an inside of an enclosure of an osmotic delivery system in which the body is insertable;    a predetermined plug thickness defined by the location of the depth surface relative to the liquid contact surface; and    a predetermined wall width defined by the location of the outer surface relative to the interior surface, at least one of the predetermined plug thickness and predetermined wall width for controlling a rate of liquid permeation through is the semipermeable body.    
   
   
       2 . The osmotic delivery system plug according to  claim 1  further comprising an insert located within the recess.  
   
   
       3 . The osmotic delivery system plug according to  claim 2 , wherein the insert is pervious to liquids.  
   
   
       4 . The osmotic delivery system plug according to  claim 1 , wherein the insert includes a top surface adjacent the depth surface of the tubular interior.  
   
   
       5 . The osmotic delivery system plug according to  claim 1 , wherein the insert includes a peripheral surface mating the interior surface of the recess.  
   
   
       6 . The osmotic delivery system plug according to  claim 1 , wherein the liquid contact surface of the semipermeable body includes a cone-shaped surface.  
   
   
       7 . A method of changing a liquid permeation rate through a semipermeable body of an osmotic delivery system to increase a delivery rate of a beneficial agent from the osmotic delivery system, the method comprising the steps of: 
 making a semipermeable body having a liquid permeability coefficient and a thickness; and    changing said thickness of said semipermeable body to alter a liquid permeation rate through said semipermeable body.    
   
   
       8 . The method according to  claim 7 , wherein said semipermeable body is located in an opening of the osmotic delivery system.  
   
   
       9 . The method according to  claim 7 , wherein said thickness of said semipermeable body is changed by cutting said semipermeable body.  
   
   
       10 . The method according to  claim 7 , wherein said thickness is changed after said semipermeable body has been inserted into an opening of the osmotic delivery system.  
   
   
       11 . The method according to  claim 7 , wherein a liquid impermeable sleeve surrounds a cylindrical surface of said semipermeable body, further comprising the step of changing a length of said liquid impermeable sleeve.  
   
   
       12 . The method according to  claim 11 , wherein said length of said semipermeable sleeve is changed when said thickness of said semipermeable body is changed.  
   
   
       13 . The method according to  claim 7 , wherein said semipermeable body is located at least partially within an enclosure of said osmotic delivery system and an enclosure length of said enclosure is changed when said thickness of said semipermeable body is changed.  
   
   
       14 . A method of varying a liquid permeation rate through a semipermeable body of an osmotic delivery system in which a liquid impermeable sleeve is mounted on the semipermeable body to vary a delivery rate of a beneficial agent from said osmotic delivery system, the method comprising the step of moving said liquid impermeable sleeve along an exterior surface of said semipermeable body to vary an amount of surface area of said exterior surface that is immediately exposed to liquids when said osmotic delivery system is located in a liquid environment of use.  
   
   
       15 . The method according to  claim 14 , wherein said semipermeable body is at least partially located within an enclosure of said osmotic delivery system, and said exterior surface is a cylindrical surface of said semipermeable body.  
   
   
       16 . The method according to  claim 14 , wherein said liquid impermeable sleeve is moved along an enclosure exterior surface of an enclosure of said osmotic delivery system when said liquid impermeable sleeve is moved along said exterior surface of said semipermeable body.  
   
   
       17 . A method of varying a liquid permeation rate through a semipermeable body of an osmotic delivery system to vary a delivery rate of a beneficial agent from the osmotic delivery system, the method comprising the step of: 
 selecting a desired liquid permeation rate through the semipermeable body of the osmotic delivery system; and    providing a plurality of semipermeable body elements in abutting relation to one another to define said semipermeable body and to achieve said selected liquid permeation rate.    
   
   
       18 . The method according to  claim 17 , further comprising the step of adding an additional semipermeable body element in abutting relation to said plurality of said semipermeable body elements to achieve another liquid permeation rate different than said selected liquid permeation rate.  
   
   
       19 . The method according to  claim 17 , further comprising the step of removing at least one of said semipermeable body elements from said plurality of said semipermeable body elements to achieve another liquid permeation rate different than said selected liquid permeation rate.  
   
   
       20 . The method according to  claim 17 , wherein said plurality of semipermeable body elements are attached to each other with an adhesive.  
   
   
       21 . An osmotic delivery system comprising: 
 a liquid impermeable enclosure having an interior holding a beneficial agent and an osmotic agent for imbibing liquid from a surrounding environment and causing delivery of said beneficial agent from said liquid impermeable enclosure;    a semipermeable body in liquid communication with said liquid impermeable enclosure for permitting liquid to permeate through said semipermeable body to said osmotic agent;    a liquid impermeable sleeve separate from said liquid impermeable enclosure and surrounding a portion of a surface of said semipermeable body such that said portion of said surface is not immediately exposed to liquid when said osmotic delivery system is located in a liquid environment of use and such that said semipermeable body includes an exposure surface defined by an area of said surface that is not surrounded by said liquid impermeable sleeve and is immediately exposed to liquids when said osmotic delivery system is located in the liquid environment of use.    
   
   
       22 . The osmotic delivery system according to  claim 21 , wherein said portion of said surface of said semipermeable body is a cylindrical surface and said liquid impermeable sleeve abuts against said cylindrical surface.  
   
   
       23 . The osmotic delivery system according to  claim 22 , wherein the exposure surface of said semipermeable body includes a surface incident to said cylindrical surface.  
   
   
       24 . The osmotic delivery system according to  claim 21 , wherein said liquid impermeable sleeve abuts said surface of said semipermeable body and is movable with respect to said surface to vary an amount of said exposure surface that is exposed to liquid when said osmotic delivery system is placed in the liquid environment of use.  
   
   
       25 . The osmotic delivery system according to  claim 21 , wherein said liquid impermeable sleeve abuts against an exterior surface of said liquid impermeable enclosure and is movable with respect to said exterior surface of said liquid impermeable enclosure.  
   
   
       26 . The osmotic delivery system according to  claim 21 , wherein the semipermeable body is positioned within an opening of said liquid impermeable enclosure of said osmotic delivery system.  
   
   
       27 . The osmotic delivery system according to  claim 21 , wherein at least one of said liquid impermeable sleeve and said enclosure includes threads such that said liquid impermeable sleeve is movable linearly with respect to said enclosure by rotating said sleeve.  
   
   
       28 . An osmotic delivery system comprising: 
 an enclosure having an interior holding a beneficial agent and an osmotic agent, said osmotic agent for imbibing liquid from a surrounding environment and causing delivery of said beneficial agent from said enclosure;    a first semipermeable body in liquid communication with said enclosure for permitting liquid to permeate through said first semipermeable body to said osmotic agent; and    a second semipermeable body abutting said first semipermeable body and in liquid communication with said first semipermeable body so as to permit liquid to permeate through said first semipermeable body and said second semipermeable body to said osmotic agent.    
   
   
       29 . The osmotic delivery system according to  claim 28 , wherein said second semipermeable body is removable from said first semipermeable body to vary a liquid permeation rate into said osmotic delivery system.  
   
   
       30 . The osmotic delivery system according to  claim 28 , wherein said second semipermeable body is attached to said first semipermeable body by an adhesive.  
   
   
       31 . The osmotic delivery system according to  claim 28 , wherein said first semipermeable body and said second semipermeable body are semipermeable layers.