Edible MCC/PGA coating composition

Abstract

An edible, hardenable coating composition is disclosed containing microcrystalline cellulose, a film forming amount of propylene glycol alginate, and a strengthening polymer, optionally in combination with at least one of a plasticizer, a surfactant, or a filler. The coating composition of the present invention may be applied to pharmaceutical and veterinary solid dosage forms, confectionery, seeds, animal feed, fertilizers, pesticide tablets, and foods and provides an elegant prompt release coating which-does not retard the release of active ingredients from the coated substrate.

What is claimed is:  
     
         1 . An edible, hardenable, prompt release coating composition comprising (a) microcrystalline cellulose, (b) a film forming amount of propylene glycol alginate, (c) a strengthening polymer and optionally (d) at least one of a plasticizer, a surface active agent and a filler.  
     
     
         2 . The coating composition of  claim 1 , comprising 5% to 50% by weight microcrystalline cellulose, 10% to 50% by weight propylene glycol alginate, and 5% to 25% by weight strengthening polymer.  
     
     
         3 . The coating composition of  claim 2 , comprising 12% to 50% by weight propylene glycol alginate.  
     
     
         4 . The coating composition of  claim 1  in which the strengthening polymer is hydroxyethylcellulose.  
     
     
         5 . The coating composition of  claim 4 , further comprising from 20% to 30% by weight plasticizer.  
     
     
         6 . The coating composition of  claim 5 , in which the plasticizer is triacetin.  
     
     
         7 . The coating composition of  claim 4 , further comprising from 1% to 5% by weight surface active agent.  
     
     
         8 . The coating composition of  claim 4 , further comprising from 10% to 30% by weight of a filler.  
     
     
         9 . The coating composition of  claim 8 , in which the filler is at least one of mannitol or maltodextrin.  
     
     
         10 . The coating composition of  claim 1 , in which the weight ratio of microcrystalline cellulose to propylene glycol alginate is in the range of 90:10 to 20:80.  
     
     
         11 . The coating composition of  claim 1 , wherein the microcrystalline cellulose has an average particle size in the range of 1 to 50 microns.  
     
     
         12 . The coating composition of  claim 10 , further comprising carrageenan in an amount of from 3% to 20% by dry weight of the composition.  
     
     
         13 . The coating composition of  claim 12 , wherein carrageenan is present in an amount in the range of 3% to 8% by dry weight of the composition and the weight ratio of propylene glycol alginate to carrageenan is in the range of 2:1 to 10:1  
     
     
         14 . The composition of  claim 12  wherein carrageenan is present in an amount in the range of 9% to 20% by dry weight of the composition and the weight ratio of propylene glycol alginate to carrageenan is in the range of 2:1 to 0.8:1.  
     
     
         15 . The coating composition of  claim 1 , wherein said composition is a dry blend.  
     
     
         16 . The coating composition of  claim 1 , wherein said composition is an aqueous dispersion.  
     
     
         17 . The coating composition of  claim 1  further comprising a coloring agent.  
     
     
         18 . A solid dosage form coated with the composition of  claim 1 .  
     
     
         19 . A method for forming an edible, hardenable, prompt release coating composition comprising 
 i) combining (a) microcrystalline cellulose, (b) a film forming amount of propylene glycol alginate, (c) a strengthening polymer and optionally (d) at least one of a plasticizer, a surface active agent and a filler; and    ii) forming a film coating by spraying an aqueous suspension of i) onto a substrate.