Hard capsules

Abstract

Publicly available pullulan hard capsule shells present certain drawbacks, notably a non fully satisfactory shell mechanical strength (i.e. shell brittleness) at shell low LOD. Improving this property is a particularly desirable goal for pullulan hard capsule shells. The present invention solves this and other objects by providing new hard pullulan capsule shells and capsules comprising (I) moisture, (II) a mono-, di-, and oligosaccharides free pullulan and (III) a setting system. Also provided are an aqueous composition and a dip-molding manufacturing method for the manufacture of such shells and capsules.

We claim: 
     
         1 . A hard capsule shell comprising a setting system, and at least one pullulan, wherein the pullulan is substantially free of mono-, di-, and oligosaccharides, wherein the amount of mono-, di-, and oligosaccharides in the pullulan is less than 2.5% by weight of pullulan on a dry solid basis, and wherein the hard capsule shell comprises between 70% and 97% of the pullulan by weight of the shell. 
     
     
         2 . The hard capsule shell according to  claim 1 , wherein the hard capsule shell comprises between 85% and 96% of the pullulan by weight of the hard capsule shell. 
     
     
         3 . The hard capsule shell according to  claim 1 , wherein the pullulan has an average molecular weight comprised between about 100 kDa and 400 kDa. 
     
     
         4 . The hard capsule shell according to  claim 1 , wherein the hard capsule shell comprises cations present in an amount of less than 3% of the hard capsule shell and the cations are selected from potassium, lithium, sodium, ammonium, calcium and magnesium. 
     
     
         5 . The hard capsule shell according to  claim 4 , wherein the cations are present in an amount of less than 2%. 
     
     
         6 . The hard capsule shell according to  claim 5 , wherein the cations are potassium. 
     
     
         7 . The hard capsule shell according to  claim 1 , further comprising a sequestering agent in an amount of between about 0% and 2.0% by weight over the weight of the hard capsule shell. 
     
     
         8 . The hard capsule shell according to  claim 7 , wherein the sequestering agent is selected from EDTA acid, acetic acid, boric acid, citric acid, edetic acid, gluconic acid, lactic acid, phosphoric acid, tartaric acid, or salts thereof, methaphosphates, dihydroxyethylglycine, lecithin or beta cyclodextrin and combinations thereof. 
     
     
         9 . The hard capsule shell according to  claim 8 , wherein the sequestering agent is acetic acid or a salt thereof. 
     
     
         10 . The hard capsule shell according to  claim 1 , wherein the setting system comprises a gelling agent in an amount between about 0.01 and 3.0% by weight over the weight of the hard capsule shell. 
     
     
         11 . The hard capsule shell according to  claim 10 , wherein the gelling agent is selected from alginates, agar gum, guar gum, locust bean gum, carrageenan, tara gum, arabic gum, ghatti gum, khaya grandifolia gum, tragacanth gum, karaya gum, pectin, arabian, xanthan, gellan gum, starch, konjac mannan, galactomannan, funoran, acetan, welan, rhamsan, furcelleran, succinoglycan, scleroglycan, schizophyllan, tamarind gum, curdlan, dextran and mixtures thereof. 
     
     
         12 . The hard capsule shell according to  claim 11 , wherein the gelling agent is carrageenan. 
     
     
         13 . The hard capsule shell according to  claim 1 , further comprising a plasticizer in an amount between about 0% and 10% by weight of such plasticizer over the weight of the hard capsule shell, the plasticizer selected from phthalate esters; citric esters; phosphoric esters; oils; butyl stearate; dibutyl sebacate; dibutyl tartrate; diisobutyl adipate; glycerol monostearate; glycerol triacetate; tributyrin; oleic acid; stearic acid; cetylic acid; myristic acid; propylene glycol; glycerol; PEG 4000; PEG 6000; and mixtures thereof. 
     
     
         14 . The hard capsule shell according to  claim 1 , further comprising a surfactant selected from sodium lauryl sulphate, dioctyl sodium sulfosuccinate, benzalkonium chloride, benzethonium chloride, trimethyltetradecylammonium bromide, fatty acid sugar esters, sorbitol esters, sucrose monolaurate, glyceryl monooleate, polyoxyethylene sorbitan fatty acid esters, polyvinyl alcohol, dimethylpolysiloxan, sorbitan esters, or lecithin. 
     
     
         15 . The hard capsule shell according to  claim 14 , wherein the surfactant is present in an amount between about 0% and 0.5% by weight of such surfactant over the weight of the hard capsule shell. 
     
     
         16 . The hard capsule shell according to  claim 1 , comprising:
 potassium in an amount of less than 2% by weight over the weight of the hard capsule shell;   acetic acid or salt thereof in an amount of between about 0% and 2.0% by weight over the weight of the shell, and the sequestering agent is acetic acid; and   carrageenan in an amount between about 0.01 and 3.0%, by weight over the weight of the hard capsule shell.   
     
     
         17 . The hard capsule shell according to  claim 1 , wherein the amount of mono-, di- and oligosaccharides in a pullulan sample is lower than 1% by weight over the total weight of the pullulan, on a dry solid basis. 
     
     
         18 . The hard capsule shell according to  claim 1 , wherein the amount of mono-, di- and oligosaccharides in a pullulan sample is lower than 0.9% by weight over the total weight of the pullulan, on a dry solid basis. 
     
     
         19 . The hard capsule shell according to  claim 1 , wherein the amount of mono-, di- and oligosaccharides in a pullulan sample is lower than 0.7% by weight over the total weight of the pullulan, on a dry solid basis. 
     
     
         20 . The hard capsule shell according to  claim 1 , wherein the amount of mono-, di- and oligosaccharides in a pullulan sample is lower than 0.6% by weight over the total weight of the pullulan, on a dry solid basis.