Processes for manufacturing polymeric microspheres

Abstract

Processes of manufacturing polymeric microspheres facilitate the generation of polymeric microspheres of size ranges smaller than 600 microns diameter by forming beads of a predetermined size from a starting material which may include a template polymer, and subsequently contacting the beads with a structural polymer. After crosslinking of the structural polymer has taken place, the template polymer may be removed to form the finished microspheres.

1 .- 36 . (canceled)  
     
     
         37 . A particle comprising a polymer and having a core region and an exterior region, wherein the core region includes first pores having a first average pore size and the exterior region includes second pores having a second average pore size that is smaller than the first average pore size.  
     
     
         38 . The particle of  claim 37 , wherein the polymer is crosslinked.  
     
     
         39 . The particle of  claim 37 , wherein the polymer is selected from the group consisting of vinyl polymers, polyacrylamides, polyethylene glycol, polyamides, polyureas, polyurethanes, and derivatives thereof.  
     
     
         40 . The particle of  claim 37 , wherein the polymer comprises a hydrophilic polymer.  
     
     
         41 . The particle of  claim 37 , wherein the polymer comprises polyvinyl alcohol.  
     
     
         42 . The particle of  claim 37 , wherein the first pores have a first average pore size of up to about 50 microns.  
     
     
         43 . The particle of  claim 42 , wherein the second pores have a second average pore size of 10 microns or less.  
     
     
         44 . The particle of  claim 37 , wherein the second pores have a second average pore size of 10 microns or less.  
     
     
         45 . The particle of  claim 37 , wherein the particle has a diameter of smaller than 600 microns.  
     
     
         46 . The particle of  claim 37 , wherein the particle has a diameter of from one micron to 50 microns.  
     
     
         47 . The particle of  claim 37 , wherein the particle has a diameter of from 50 microns to 100 microns.  
     
     
         48 . The particle of  claim 37 , wherein the particle has a diameter of from 100 microns to 600 microns.  
     
     
         49 . The particle of  claim 37 , wherein the particle has a diameter of from 600 microns to 1000 microns.  
     
     
         50 . A particle comprising a polymer comprising polyvinyl alcohol, the particle having a core region and an exterior region, wherein the core region includes first pores having a first average pore size of up to about 50 microns and the exterior region includes second pores having a second average pore size of 10 microns or less.  
     
     
         51 . The particle of  claim 50 , wherein the particle has a diameter of smaller than 600 microns.  
     
     
         52 . The particle of  claim 50 , wherein the particle has a diameter of from 600 microns to 1000 microns.