Biodegradable drug delivery system

Abstract

A drug delivery system (DDS) comprised of segmented biodegradable implants sized and suitable for implantation in an ocular region or site and methods for treating ocular conditions. The segmented implants provide an extended release of an active agent at a therapeutically effective amount for a period of time between 50 days and one year, or longer, and permit the DDS to have segments that possess individual and different drug release characteristics.

What is claimed is: 
     
         1 . A drug delivery system for treating an ocular condition, the drug delivery system comprising a bioerodible implant, said implant comprising a plurality of segments, wherein:
 (a) each segment comprises (i) an active agent and (ii) a bioerodible polymer;   (b) at least one of the segments has drug release characteristics different from the other segments;   (c) each segment has a (i) a longitudinal axis; and (ii) at least one end having a cut surface that is at an angle to the longitudinal axis of less than 90°, or having at least one end which is of beveled shape; and   (d) the segments are joined together in a manner to permit separation of the segments from each other in situ into individual segments following intraocular implantation of the drug delivery system into a patient;   wherein the active agent of each segment is independently selected from the group consisting of bimatoprost, brimonidine, cyclosporine, dexamethasone, tazarotene and timolol.   
     
     
         2 . The drug delivery system of  claim 1  for treating an ocular condition, the drug delivery system comprising a bioerodible implant, said implant comprising a plurality of rod shaped segments, wherein:
 a) each segment comprises (i) an active agent for treating the ocular condition and (ii) a bioerodible polymer; 
 b) the segments are joined together at the ends thereof to form a contiguous rod-shaped implant; and 
 c) the segments are joined at the ends thereof in a manner to permit separation of the segments from each other in situ into individual segments following implantation into the ocular region of a patient. 
 
     
     
         3 . The drug delivery system according to  claim 2 , the segments being joined together in a matrix comprising a bioerodible polymer in a manner to permit separation of the segments from each other in situ into individual segments following implantation into the ocular region of a patient. 
     
     
         4 . The drug delivery system according to  claim 1 , wherein the bioerodible polymer comprises at least one member selected from the group consisting of poly(lactide) polymers and poly(lactide-co-glycolide) copolymers. 
     
     
         5 . The drug delivery system according to  claim 1 , wherein the segments further comprise at least one excipient that modifies the erosion characteristics of the bioerodible polymer. 
     
     
         6 . The drug delivery system according to  claim 5 , wherein the excipient is a member selected from the group consisting of long chain fatty alcohols, cholesterol, and high molecular weight polyethylene glycol polymers. 
     
     
         7 . The drug delivery system according to  claim 5 , wherein the bioerodible polymer comprises a poly(D,L-lactide-co-glycolide) copolymer with a monomer ratio in the range of 50:50 to 85:15. 
     
     
         8 . The drug delivery system according to  claim 1 , wherein at least one of the segments releases all active agent within one week of implantation and at least one of the segments begins releasing the active agent after one week post-implantation. 
     
     
         9 . The drug delivery system according to  claim 8 , wherein at least one of the segments begins releasing active agent at 12 weeks post-implantation. 
     
     
         10 . The drug delivery system according to  claim 1 , wherein at least one of the segments releases the active agent from 3 to 6 months post-implantation. 
     
     
         11 . The drug delivery system according to  claim 1 , wherein active agent is released from one of the segments within the first week after implantation, but no active agent is released from any of the segments for some period of time after the first week post implantation. 
     
     
         12 . The drug delivery system according to  claim 1 , wherein at least some of the segments comprise a first active agent and other of the segments comprise a second active agent. 
     
     
         13 . The drug delivery system according to  claim 1 , wherein each of the segments has drug release characteristics different from all the other segments. 
     
     
         14 . The drug delivery system according to  claim 1 , wherein the individual segments separate from each other immediately following injection into the patient's eye. 
     
     
         15 . The drug delivery system according to  claim 1 , wherein the individual segments separate from each other immediately upon administration to the patient. 
     
     
         16 . A drug delivery system for treating an ocular condition, the drug delivery system comprising a bioerodible implant, said implant comprising a plurality of segments, wherein:
 a) each segment comprises (i) an active agent and (ii) a bioerodible polymer; and   b) each of the segment ends are beveled or shaped in a manner to permit separation of the segments from each other immediately following injection of the drug delivery system into a patient.   
     
     
         17 . The drug delivery system of  claim 16 , wherein at least one of the segments has drug release characteristics different from the other segments. 
     
     
         18 . The drug delivery system according to  claim 16 , wherein the active agent of each segment is independently selected from a steroid, an anti-inflammatory compound, or an anti-angiogenesis compound. 
     
     
         19 . The drug delivery system according to  claim 16 , wherein at least one of the segments comprises an active agent which acts to inhibit the formation of VEGF or to inhibit the binding of VEGF to its VEGF receptor.