Tablets and methods for modified release of hydrophilic and other active agents

Abstract

The invention provides a tablet and methods for making the tablet comprising a gel-forming material and at least one particle comprising an active agent in contact with a coating material to modify release of the active agent.

What is claimed is:  
     
         1 . A tablet comprising: 
 at least one particle comprising a hydrophilic active agent in contact with a coating material to modify release of the active agent; and    a gel-forming material comprising: 
 a polymer; and  
 a gelation facilitator agent having a solubility higher than about 0.1 gram/ml in water at a temperature of about 20° C.  
   
     
     
         2 . The tablet of  claim 1 , wherein the particle comprises the active agent and a coating material on or around the active agent.  
     
     
         3 . The tablet of  claim 1 , wherein the hydrophilic active agent has a water solubility of at least about 30 mg/ml at a temperature of about 25° C.  
     
     
         4 . The tablet of  claim 1 , wherein the particle has a size between about 50 μm to about 5 mm.  
     
     
         5 . The tablet of  claim 1 , wherein the particle has a size between about 100 μm to about 3 mm.  
     
     
         6 . The tablet of  claim 1 , wherein the particle has a size between about 300 μm to about 2 mm.  
     
     
         7 . The tablet of  claim 1 , wherein the tablet comprises a plurality of the particles and wherein the gel-forming material forms a matrix for the plurality of the particles.  
     
     
         8 . The tablet of  claim 1 , wherein the active agent is in the form of a crystal or a granule.  
     
     
         9 . The tablet of  claim 8 , wherein the particle comprises a plurality of active agent crystals or granules.  
     
     
         10 . The tablet of  claim 2 , wherein the coating material slows release of the active agent from the tablet.  
     
     
         11 . The tablet of  claim 2 , wherein the coating material is flexible.  
     
     
         12 . The tablet of  claim 2 , wherein the coating material is selected from the group consisting of a natural polymer, a semi-synthetic polymer, and a synthetic polymer.  
     
     
         13 . The tablet of  claim 11 , wherein the coating material comprises chitosan, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, cellulose acetate membrane, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate, hydroxypropylmethylcellulose phthalate, polyacrylic acid, polyvinyl acetate, poly(vinylacetate phthalate), poly(vinyl alcohol), poly(vinyl pyrrolidone), poly(lactic acid), poly(glycolic acid), poly(lactic/glycolic acid), poly(dimethyl silicone), poly(hydroxyethyl methacrylate), poly(ethylene/vinyl acetate), poly(ethylene/vinyl alcohol), or a mixture thereof.  
     
     
         14 . The tablet of  claim 10 , wherein the coating material further comprises a plasticizer, a stabilizer, or both.  
     
     
         15 . The tablet of  claim 1 , wherein the polymer comprises a polyethylene oxide polymer.  
     
     
         16 . The tablet of  claim 1 , wherein the gelation facilitator agent comprises a polyethylene glycol.  
     
     
         17 . The tablet of  claim 1 , wherein the polymer to the gelation facilitator agent ratio is between about 1:9 to about 9:1 by weight.  
     
     
         18 . The tablet of  claim 1 , wherein the polymer to the gelation facilitator agent ratio is between about 3:7 to about 7:3 by weight.  
     
     
         19 . The tablet of  claim 1 , wherein the polymer to the gelation facilitator agent ratio is between about 4:6 to about 6:4 by weight.  
     
     
         20 . The tablet of  claim 1 , wherein the tablet has a hardness of at least about 2 kp.  
     
     
         21 . The tablet of  claim 1 , wherein the tablet has a hardness of between about 2 kp and about 10 kp.  
     
     
         22 . The tablet of  claim 1 , wherein the tablet provides a sustained release of the active agent for at least about 12 hours.  
     
     
         23 . The tablet of  claim 1 , the tablet further comprising a non-hydrophilic active agent.  
     
     
         24 . The tablet of  claim 2 , wherein the tablet comprises at least two different types of particles with different active agents.  
     
     
         25 . The tablet of  claim 24 , wherein the particles comprise at least two different types of particles with different coating materials.  
     
     
         26 . The tablet of  claim 1 , wherein the distribution of the particles in the tablet is non-random.  
     
     
         27 . The tablet of  claim 1 , wherein the tablet is a multilayered tablet.  
     
     
         28 . The tablet of  claim 1 , wherein at least two of the layers of the multilayered tablet comprise a different amount of the particles or at least two different types of active agents.  
     
     
         29 . The tablet of  claim 1 , wherein the particle is concentrated at the core of the tablet.  
     
     
         30 . The tablet of  claim 29 , wherein the tablet provides a delay on the onset of release of the active agent for at least about 2 hours.  
     
     
         31 . The tablet of  claim 1 , wherein the polymer comprises a polyethylene oxide polymer and wherein the gelation facilitator agent comprises a polyethylene glycol.  
     
     
         32 . The tablet of  claim 31 , wherein the tablet provides a sustained release of the active agent for at least about 12 hours.  
     
     
         33 . A method for producing a tablet, the method comprising: 
 (1) mixing a formulation comprising: 
 (a) at least one particle comprising a hydrophilic active agent in contact with a coating material to modify release of the active agent;  
 (b) a polymer; and  
 (c) a gelation facilitator agent having a solubility higher than about 0.1 gram/ml in water at a temperature of about 20° C.; and  
   (2) compressing the formulation to produce the tablet.    
     
     
         34 . The method of  claim 33 , wherein the particle comprises the active agent and a coating material on the active agent.  
     
     
         35 . The method of  claim 33 , wherein the active agent has a water solubility of at least about 30 mg/ml at a temperature of about 25° C.  
     
     
         36 . The method of  claim 33 , wherein the active agent is in the form of a crystal or a granule.  
     
     
         37 . The method of  claim 36 , wherein the particle comprises a plurality of active agent crystals or active agent granules.  
     
     
         38 . The method of  claim 33 , wherein the tablet comprises a plurality of the particles and wherein the gel-forming material forms a matrix for the plurality of the particles.  
     
     
         39 . The method of  claim 34 , wherein the coating material comprises chitosan, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, cellulose acetate membrane, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate, hydroxypropylmethylcellulose phthalate, polyacrylic acid, polyvinyl acetate, poly(vinylacetate phthalate), poly(vinyl alcohol), poly(vinyl pyrrolidone), poly(lactic acid), poly(glycolic acid), poly(lactic/glycolic acid), poly(dimethyl silicone), poly(hydroxyethyl methacrylate), poly(ethylene/vinyl acetate), poly(ethylene/vinyl alcohol), or a mixture thereof.  
     
     
         40 . The method of  claim 34 , wherein the particle is produced by spraying the coating material on the active agent.  
     
     
         41 . The method of  claim 34 , wherein the coating material is flexible so that it does not crack during compressing the formulation into the tablet.  
     
     
         42 . The method of  claim 34 , wherein the coating material is hydrophobic.  
     
     
         43 . The method of  claim 41 , wherein the coating material further includes a plasticizer, a stabilizer, or both.  
     
     
         44 . The method of  claim 33 , wherein the polymer is a polyethylene oxide polymer.  
     
     
         45 . The method of  claim 33 , wherein the gelation facilitator agent is a polyethylene glycol.  
     
     
         46 . The method of  claim 33 , wherein in step (1), the polymer is granulated with the gelation facilitator agent.  
     
     
         47 . The method of  claim 33 , wherein in step (1), the polymer and the gelation facilitator agent are granulated with the particles.  
     
     
         48 . The method of  claim 33 , wherein the tablet is compressed to a hardness of at least about 2 kp.  
     
     
         49 . The method of  claim 33 , wherein the tablet is compressed to a hardness of between about 2 kp to about 10 kp.  
     
     
         50 . The method of  claim 33 , wherein the particles are non-randomly distributed throughout the tablet.  
     
     
         51 . The method of  claim 33 , wherein the tablet is multilayered.