Colonic drug delivery composition

Abstract

A colonic drug delivery composition is provided and comprises a starch capsule containing a drug, the starch capsule being provided with a coating such that the drug will only be released from the capsule in the colon. The coating may be a pH sensitive material, a redox sensitive material, or a material broken down by specific enzymes or bacteria present in the colon. The drug to be delivered may be one for local action in the colon or a systemically active drug to be absorbed from the colon.

1 . A drug delivery composition for delivering a drug to the colonic region comprising a starch capsule containing the drug and wherein the starch capsule is provided with a coating such that the drug is predominantly released from the capsule in the colon and/or terminal ileum.  
     
     
         2 . A drug delivery composition according to    claim 1    wherein the coating comprises a material which dissolves at a pH of 5 or above.  
     
     
         3 . A drug delivery composition according to    claim 1    wherein the coating comprises a material which is redox-sensitive.  
     
     
         4 . A drug delivery composition according to    claim 3    wherein the coating comprises an azopolymer or a disulphide polymer.  
     
     
         5 . A drug delivery composition according to    claim 1    wherein the coating comprises a material which is degraded by enzymes or bacteria present in the colon.  
     
     
         6 . A drug delivery composition according to    claim 2    wherein the coating comprises methyl methacrylate or a copolymer of methacrylic acid and methyl methacrylate.  
     
     
         7 . A drug delivery composition according to    claim 2    wherein the coating comprises a cellulose ester.  
     
     
         8 . A drug delivery composition according to any one of the preceding claims wherein the coating has a thickness in the range of 80 μm to 300 μm.  
     
     
         9 . A drug delivery according to any one of the preceding claims wherein the drug is one which acts locally in the colon.  
     
     
         10 . A drug delivery composition according to any one of    claims 1    to    8    wherein the drug is for systemic delivery and systemic action.  
     
     
         11 . A drug delivery composition according to any one of    claims 1    to    8    wherein the drug is a vaccine for delivery to the lymphoid tissue of the colon.  
     
     
         12 . A method of delivering a drug to the colonic region of a human or mammal comprising orally administering a drug delivery composition comprising a starch capsule containing the drug and wherein the starch capsule is provided with a coating such that the drug is predominantly released frown the capsule in the colon and/or terminal ileum.  
     
     
         13 . A method of delivering a vaccine to the lymphoid tissue present in the colon of a human or mammal comprising orally administering a drug delivery composition comprising a starch capsule containing the vaccine and wherein the starch capsule is provided with a coating such that the vaccine is predominantly released from the capsule in the colon and/or terminal ileum.