Method of preparing enteric hard capsule and enteric hard capsule prepared thereby

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.