Oral dosage form for controlled drug release

Abstract

An oral dosage form comprising, (i) an erodable core, which core comprises a pharmaceutically active weak base or a pharmaceutically acceptable salt or solvate thereof; and (ii) an erodable coating surrounding said core, which coating comprises one or more openings extending substantially completely through said coating but not penetrating said core and communicating from the environment of use to said core; characterised in that release of the pharmaceutically active weak base or a pharmaceutically acceptable salt or solvate thereof from the dosage form occurs through the said opening(s) by the erosion of said erodable core and through erosion of said erodable coating under pre-determined pH conditions; a process for preparing such a dosage form and the use of such a dosage form in medicine.

1 . An oral dosage form comprising, 
 (i) an erodable core, which core comprises a pharmaceutically active weak base or a pharmaceutically acceptable salt or solvate thereof; and    (ii) an erodable coating around said core, which coating comprises one or more openings extending substantially completely through said coating but not penetrating said core and communicating from the environment of use to said core;    characterised in that release of the pharmaceutically active weak base or a pharmaceutically acceptable salt or solvate thereof from the dosage form occurs through the said opening(s) by the erosion of said erodable core and through erosion of said erodable coating under pre-determined pH conditions.    
     
     
         2 . An oral dosage form according to  claim 1  in which the erodable coating erodes at pH>4.5.  
     
     
         3 . An oral dosage form according to  claim 1  in which the erodable coating material is selected from polymethacrylate polymers, coprocessed polyvinylacetate phthalate, cellulose acetate trimellitate, cellulose acetate phthalate, shellac, hydroxyropyl-methylcellulose phthalate polymers and their copolymers, and blends thereof.  
     
     
         4 . An oral dosage form according to  claim 1  in which the erodable coating has a thickness in the range 0.05 to 0.5 mm.  
     
     
         5 . An oral dosage form according to  claim 1  in which the opening(s) sizes are in the range 0.5 mm to 8 mm.  
     
     
         6 . An oral dosage form according to  claim 1  in which the erodable coating comprises two openings.  
     
     
         7 . An oral dosage form according to  claim 1 , in which the erodable core is in a multi-layered form.  
     
     
         8 . An oral dosage form according to  claim 1  in which the opening(s) in the erodable coating comprise about 10 to 70% of the total face area of the dosage form.  
     
     
         9 . An oral dosage form according to  claim 1  in which the core is predominantly hydroxypropylmethyl cellulose and lactose.  
     
     
         10 . An oral dosage form according to  claim 1  in which the pharmaceutically acceptable weak base is selected from the Primary Compounds of the invention or a pharmaceutically acceptable salt or solvate thereof.  
     
     
         11 . An oral dosage form according to  claim 10 , in which the pharmaceutically acceptable weak base is 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]benzyl]thiazolidine-2,4-dione (‘Compound A’) or a pharmaceutically acceptable salt or solvate thereof.  
     
     
         12 . A process for the preparation of an oral dosage form according to  claim 1 , which process comprises: 
 (a) preparing an erodable tablet core;    (b) coating the core with a material with pH-dependent erodability; and    (c) creating one or more openings in the coating, said opening(s) extending substantially completely through said coating but not penetrating said core and communicating from the environment of use to said core.    
     
     
         13 . A method for the treatment and/or prophylaxis of disorders in a human or non-human mammal susceptible to treatment by a pharmaceutically acceptable weak base, which comprises administering an oral dosage form according to  claim 1  comprising a pharmaceutically acceptable weak base or a pharmaceutically acceptable salt or solvate thereof to a human or non-human mammal in need thereof.