Shin-etsu Chemical Co., Ltd.

Akiko Tsuchida

Akira Kitamura

Mitsuo Narita

Taishi Kitaguchi

Yasuyuki Hirama

Kentaro Miki

There is provides a method for producing sieved low-substituted hydroxypropyl cellulose (L-HPC) at improved yield, while maintaining flowability and tablet properties. More specifically, there is provided a method for producing sieved L-HPC including a first sieving step of sieving L-HPC having a hydroxypropoxy group content of 5 to 16% by mass with a sieving shaker with horizontal movement of a sieve surface to obtain first sieve-residual L-HPC and first sieve-passed L-HPC, a second sieving step of sieving the first sieve-residual L-HPC with a sieving shaker with vertical movement of a sieve surface to obtain second sieve-residual L-HPC and second sieve-passed L-HPC, and a step of combining the first sieve-passed L-HPC and the second sieve-residual L-HPC to obtain the sieved L-HPC.

Method for producing sieved low-substituted hydroxypropyl cellulose

There is provided a method for producing hypromellose acetate succinate (HPMCAS), the method not requiring any special device and facilitating removal of impurities. More specifically, there is provided a method for producing HPMCAS, including an esterification step of esterifying hypromellose with an acetylating agent and a succinoylating agent in the presence of an aliphatic carboxylic acid to obtain a reaction product solution containing HPMCAS; a precipitation step of precipitating the HPMCAS by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCAS; a neutralization step of neutralizing the suspension with a basic substance to obtain a neutralized suspension; and a washing step of washing the HPMCAS contained in the neutralized suspension to obtain the washed HPMCAS.

Method for producing hypromellose acetate succinate

There is provided a method for producing hypromellose phthalate (HPMCP), the method not requiring any special device, and facilitating removal of impurities. More specifically, there is provided a method for producing HPMCP, including an esterification step of esterifying hypromellose with a carboxybenzoylating agent in the presence of an aliphatic carboxylic acid to obtain a reaction product solution containing HPMCP; a precipitation step of precipitating the HPMCP by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCP; a neutralization step of neutralizing the suspension with a basic substance to obtain a neutralized suspension; and a washing step of washing the HPMCP contained in the neutralized suspension to obtain the washed HPMCP.

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Niigata, Japan

Akiko Tsuchida