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Process for producing cellulose ether acetate succinate

A technology of ether succinate and cellulose acetate, applied in the field of preparing cellulose acetate ether succinate, can solve the problems of difficult handling, insufficient film strength and the like

Inactive Publication Date: 2017-08-18
DOW GLOBAL TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the viscosity is less than 3 cp, the strength of the finally obtained coating film for solid enteric pharmaceutical preparations is insufficient, while if it exceeds 10 cp, the viscosity observed when the cellulose ether is dissolved in a solvent to undergo a substitution reaction becomes extremely high. High and homogeneous mixing and disposal for further processing is extremely difficult

Method used

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  • Process for producing cellulose ether acetate succinate
  • Process for producing cellulose ether acetate succinate
  • Process for producing cellulose ether acetate succinate

Examples

Experimental program
Comparison scheme
Effect test

example

[0053] All parts and percentages are by weight unless otherwise mentioned. In the examples, the following test procedure was used.

[0054] Viscosity of hydroxypropylmethylcellulose (HPMC) samples

[0055] The viscosity of cellulose ethers was determined as a 2% by weight aqueous solution at 20°C as described in the United States Pharmacopoeia (USP 35, "Hypromellose", pp. 423-424 and 3467-3469). Viscosities of less than 600 mPa·s were determined by Ubbelohde viscometry and viscosities of 600 mPa·s or greater were determined using a Brookfield viscometer as described in the US Pharmacopoeia. A description of the preparation of 2 wt% HPMC solutions and the conditions for Ubbelohde and Brookfield viscosity measurements is published in the United States Pharmacopoeia (USP 35, "Hypromellose", pages 423-424 and 3467-3469 and ASTM D-445 cited therein and ISO 3105).

[0056] Viscosity of hydroxypropylmethylcellulose acetate succinate (HPMCAS)

[0057] A 2.0% by weight solution ...

example 9 and 10

[0093] Generate HPMCAS of Examples 9 and 10

[0094] Glacial acetic acid, acetic anhydride, succinic anhydride, HPMC E100LV, sodium acetate (anhydrous) and potassium chlorate were introduced into a 1 L volume reaction vessel in the amounts listed in Table 3 below. The weight ratios of reactants in Examples 9 and 10 corresponded to those in Examples 1-5 (Table 1) of US Patent No. 4,226,981, except that potassium chlorate was not used in the procedure of US Patent No. 4,226,981.

[0095] Glacial acetic acid is readily absorbed by HPMC powder. The reaction mixture had a solid appearance and could not be stirred sufficiently to obtain a homogeneous reaction mixture. The mixture was heated at 80°C for 5 hours to effect esterification. As the esterification and partial depolymerization proceed, the viscosity of the reaction mixture decreases and the reaction mixture can be sufficiently stirred to obtain a homogeneous mixture. After 5 hours, HPMCAS was precipitated from the reac...

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Abstract

A process for producing a cellulose ether acetate succinate comprises the step of reacting cellulose ether with acetic anhydride, succinic anhydride and an depolymerizing agent, wherein the cellulose ether has an initial viscosity of at least 50 mPa.s, measured as a 2 weight% solution in water at 20 DEG C, and the reaction of the cellulose ether with acetic anhydride, succinic anhydride and the depolymerizing agent is conducted simultaneously or in sequence in one reaction device.

Description

technical field [0001] The invention relates to a method for preparing cellulose acetate ether succinate. Background technique [0002] Cellulose acetate ether succinates, such as hydroxyalkylmethylcellulose acetate succinates, their uses, and methods for their preparation are generally known in the art. Various known hydroxyalkylmethylcellulose acetate succinates are suitable as enteric polymers for pharmaceutical dosage forms, such as hydroxypropylmethylcellulose acetate succinate (HPMCAS). Enteric polymers are those polymers that are resistant to dissolution in the acidic environment of the stomach. Dosage forms coated with such polymers prevent drug inactivation or degradation in an acidic environment or prevent the drug from irritating the stomach. [0003] U.S. Patent No. 4,226,981 discloses a method for the preparation of mixed esters of cellulose ethers, such as hydroxypropylmethylcellulose acetate succinate (HPMCAS), by using a base carboxylate as an esterificatio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B13/00C09D101/32C08L1/32
CPCC08B13/00C08L1/32C09D101/32A61K47/38A61K9/2886A61K9/2866C08K3/16
Inventor O·彼得曼M·斯皮尔
Owner DOW GLOBAL TECH LLC