The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 26, 2022
Filed:
Oct. 09, 2020
Shin-etsu Chemical Co., Ltd., Tokyo, JP;
Junichi Matsubara, Joetsu, JP;
Naosuke Maruyama, Joetsu, JP;
Mitsuhiro Yoshida, Joetsu, JP;
Kazuki Kikuchi, Joetsu, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
Provided are HPMCAS powder having high solubility when dissolved in a solvent and being capable of suppressing generation of undissolved materials; and a method for producing the powder. More specifically, provided is hypromellose acetate succinate powder having an average ratio of L to D of from 2.0 to 3.0, wherein L and D mean maximum and minimum diameters of each particle, respectively. Also provided is a method for producing a hypromellose acetate succinate, comprising the steps of: dissolving hypromellose powder in a solvent, esterifying the dissolved hypromellose with succinic anhydride and acetic anhydride in the presence of a catalyst to obtain a reaction mixture, and mixing the reaction mixture with water to precipitate hypromellose acetate succinate, wherein the reaction mixture just before being mixed with the water has a viscosity of from 100 to 200 Pa·s.