Enteric soft capsules
A gel mass is provided that is useful in manufacturing enteric soft or hard capsules, or enteric tablets without coating.
1. An enteric soft capsule shell formed from a gel mass comprising:
(a) a gelatin,
(b) an acid-insoluble polymer;
(c) an alkaline aqueous solvent; and
(d) a plasticizer;
wherein the gelatin and acid-insoluble polymer together comprise 45% by weight of the gel mass;
the ratio of acid-insoluble polymer to gelatin is from 30:70 to 45:55 by weight;
the final pH of the gel mass is less than or equal to about 9 pH units; and
the final moisture content of the enteric soft capsule shell formed from the gel mass composition is from about 2% to about 10%.
2. The enteric soft capsule shell of claim 1 , wherein the gelatin comprises at least about 25% by weight of the gel mass.
3. The enteric soft capsule shell of claim 1 , wherein gelatin comprises about 25% to about 36% by weight of the gel mass.
4. The enteric soft capsule shell of claim 1 , wherein the acid-insoluble polymer comprises at most about 20% by weight of the gel mass.
5. The enteric soft capsule shell of claim 1 , wherein the acid-insoluble polymer comprises about 8% to about 20% by weight of the gel mass.
6. The enteric soft capsule shell of claim 1 , wherein the gelatin is extracted from animal bones or skins, and has a bloom value of about 100 to about 250.
7. The enteric soft capsule shell of claim 1 , wherein the acid-insoluble polymer is selected from the group consisting of acrylic and methacrylic acid copolymers and cellulose acetate esters.
8. The enteric soft capsule shell of claim 7 , wherein the acid-insoluble polymer is methacrylic acid copolymers.
9. The enteric soft capsule shell of claim 1 , wherein the plasticizer is selected from the group consisting of sorbitol, glycerol, polyethylene glycol, poly-alcohols with 3 to 6 carbon atoms, citric acid, citric acid esters, triethyl citrate, and combinations thereof.
10. The enteric soft capsule shell of claim 1 , wherein the alkaline aqueous solvent comprises an alkali selected from the group consisting of ammonia, sodium hydroxide, potassium hydroxide, ethylenediamine, hydroxylamine, and tri-ethanolamine.
11. The enteric soft capsule shell of claim 1 , wherein the alkaline aqueous solvent comprises a volatile alkali.
12. The enteric soft capsule shell of claim 11 , wherein the volatile alkali is selected from the group consisting of ammonia and ethylenediamine.
13. The enteric soft capsule shell of claim 1 , wherein the alkaline aqueous solvent is a hydroalcoholic solution.
14. The enteric soft capsule shell of claim 1 , where the final pH of the gel mass is less than or equal to about 8.5.
15. The enteric soft capsule shell of claim 1 , wherein the gel mass has a moisture content of from about 9% to about 35%.
16. The enteric soft capsule shell of claim 1 , wherein the final moisture content of the enteric soft capsule shell formed from the gel mass composition is from about 4% to about 8%.
17. The enteric soft capsule shell of claim 1 , wherein the ratio of plasticizer to gelatin is from about 1:9 to about 1:1 by weight.
18. The enteric soft capsule shell of claim 1 , wherein the ratio of plasticizer to gelatin is about 1:2 by weight.
19. The enteric soft capsule shell of claim 1 , wherein the plasticizer comprises about 17% of the gel mass.
20. The enteric soft capsule shell of claim 1 , wherein the thickness of the capsule shell is from about 0.015 inches to about 0.050 inches.
21. A process of manufacturing enteric soft capsules, the process comprising
(a) preparing a gel mass of claim 1 ;
(b) casting the gel mass into films using heat-controlled drums or surfaces; and
(c) forming a soft capsule using rotary die technology.
22. The enteric soft capsule shell of claim 1 , wherein the plasticizer is glycerol.
23. The enteric soft capsule shell of claim 1 , wherein the alkaline aqueous solvent is ammonia.
24. The enteric soft capsule shell of claim 7 , wherein the cellulose acetate ester is selected from the group consisting of phthalate, butyrate, hydropropyl methylcellulose phthalate and salts thereof.