Patent ID: 8710105

Claim:
A method of preparing an enteric hard capsule, the method comprising: dissolving an enteric base material, a capsule forming aid, and a neutralizing agent in water at room temperature to prepare an aqueous composition; heating the aqueous composition to a first temperature that is higher than a gelation start temperature of the aqueous composition by about 1° C. to about 20° C.; cooling the heated aqueous composition to a second temperature that is lower than the gelation start temperature by about 15° C. to about 40° C.; immersing a mold pin heated to a third temperature that is higher than the gelation start temperature into the aqueous composition by about 10° C. to about 40° C.; removing the mold pin from the aqueous composition to obtain a film coated on the mold pin; maintaining the film on the mold pin at a fourth temperature that is higher than the gelation start temperature for a first time period to fix the film onto the mold pin, wherein the fourth temperature is from about 60° C. to about 80° C., and the first time period is from about 1 minute to about 15 minutes; and drying the fixed film at a fifth temperature for a second time period to obtain a capsule shell, wherein the fifth temperature is from about 20° C. to about 40° C., and the second time period is from about 30 minutes to about 60 minutes, wherein the enteric base material comprises at least one compound selected from the group consisting of hydroxypropyl methyl cellulose phthalate (HPMCP) and hydroxypropyl methyl cellulose acetate succinate (HPMCAS), wherein the capsule forming aid comprises at least one compound selected from the group consisting of hydroxypropyl methylcellulose (HPMC) and methylcellulose (MC), wherein the neutralizing a agent comprises an alkaline material.