Method for producing low-substituted hydroxypropyl cellulose
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Solution Overview
Problem
Existing methods for producing low-substituted hydroxypropyl cellulose (L-HPC) result in insufficient disintegratability when used in wet granulation tableting methods, despite maintaining sufficient compactibility.
Innovation Solution
A method involving the use of a screw press to remove liquid from crude L-HPC to achieve a water content of 50 to 60% by mass, followed by drying and pulverizing, with specific conditions for the screw press such as temperature and rotation speed, to enhance swelling force and disintegratability while preserving compactibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If L-HPC is produced by etherifying alkali cellulose and dispersing in aqueous acid solution as per conventional method, then compactibility is sufficient, but disintegratability is insufficient
Solution Approach 1:
The invention changes the water content parameter of L-HPC from conventional levels to specifically 50-60% by mass through controlled liquid removal using a screw press. This parameter change enables the L-HPC to exhibit both good disintegratability and compactibility, resolving the contradiction between these two properties.
Solution Approach 2:
The invention replaces conventional drying methods with a screw press mechanical system to remove liquid from crude L-HPC. This mechanical approach allows precise control of water content to 50-60% by mass, achieving the desired balance between disintegratability and compactibility that cannot be obtained by traditional drying alone.
2Reliability
If L-HPC water content is reduced to enhance disintegratability, then swelling force improves, but powder physical properties and compactibility may be affected
Solution Approach 1:
The invention optimizes the water content parameter to a specific range of 50-60% by mass. This controlled parameter change enhances swelling force and disintegratability while maintaining stable powder physical properties and compactibility, avoiding the adverse effects of excessive water removal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The produced L-HPC exhibits improved disintegratability and compactibility, allowing for rapid drug release and effective tablet formation.
Implementation Method 1
using a screw press to remove liquid from the crude low-substituted hydroxypropyl cellulose
Implementation Method 2
using a screw press to remove liquid from the crude low-substituted hydroxypropyl cellulose to obtain purified low-substituted hydroxypropyl cellulose having a water content of 50 to 60% by mass
Implementation Method 3
reacting the alkali cellulose with propylene oxide to obtain a reaction product
Implementation Method 4
dispersing the reaction product into a solution containing at least an acid to partially solubilize the reaction product
Implementation Method 5
neutralizing the reaction product with an additional amount of the acid to precipitate crude low-substituted hydroxypropyl cellulose
Implementation Method 6
drying and pulverizing the purified
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Provided is a method for producing low-substituted hydroxypropyl cellulose having favorable disintegratability while maintaining sufficient compactibility. The method essentially includes the steps of: bringing an alkali metal hydroxide solution into contact with a pulp to prepare alkali cellulose; reacting the alkali cellulose with propylene oxide to obtain a reaction product; dispersing the reaction product into a solution containing at least an acid to partially solubilize the reaction product, and then neutralizing the reaction product with an additional amount of acid to precipitate crude low-substituted hydroxypropyl cellulose; using a screw press to remove liquid from the crude low-substituted hydroxypropyl cellulose to obtain purified low-substituted hydroxypropyl cellulose having a water content of 50 to 60% by mass; and drying and pulverizing the purified low-substituted hydroxypropyl cellulose, wherein the method produces low-substituted hydroxypropyl cellulose having a hydroxypropoxy group content of 5.0 to 16.0% by mass.