Cellulose Ether Sustained Release Dosage Forms
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Solution Overview
Problem
Current sustained release pharmaceutical dosage forms using cellulose ethers struggle to maintain controlled release of active ingredients over an extended period without compromising the particle size of the cellulose ether, which affects the efficacy and duration of drug delivery.
Innovation Solution
A sustained release dosage form is developed using a polymeric matrix comprising cellulose ethers with specific substituent patterns, such as anhydroglucose units joined by 1-4 linkages and having methyl groups, hydroxyalkyl groups, and optional alkyl groups, with a unique distribution of methyl groups and an onset dissolution temperature of at least 40°C, to control the release of active ingredients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional cellulose ethers are used as polymeric matrix, then the dosage form can be manufactured, but the release of active ingredient cannot be sustained over extended period
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of cellulose ether through specific substitution patterns (s23/s26 ratio ≤ 0.31) and hydroxyalkyl substitution degrees (MS 0.05-1.00). These parameter modifications transform conventional cellulose ether into a specialized polymer that forms stable gel layers, enabling sustained release over extended periods while maintaining controlled release performance.
Solution Approach 2:
The patent creates a composite polymeric matrix system by combining cellulose ether with specific substituent patterns with the active ingredient and optional adjuvants. This composite structure, where the modified cellulose ether serves as the release-controlling matrix, enables both sustained release duration and reliable controlled release performance that neither component could achieve alone.
2Manufacturing precision
If particle size of cellulose ether is reduced to improve release control, then release rate can be controlled, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the chemical parameters of cellulose ether (substitution pattern s23/s26 ≤ 0.31, hydroxyalkyl MS 0.05-1.00) to achieve release rate control without relying solely on particle size reduction. This chemical modification allows the use of coarser particles while maintaining precise release control, thereby reducing manufacturing complexity.
Solution Approach 2:
The patent replaces the mechanical approach of fine particle size control with a chemical approach using modified cellulose ether structure. Instead of relying on mechanical size reduction to control release rate, the chemically modified polymer provides inherent release control through its gel-forming properties, substituting mechanical precision requirements with chemical structure design.
3Stability of the object's composition
If gel layer formation is accelerated to prevent tablet disintegration, then structural integrity is maintained, but release duration is reduced
Solution Approach 1:
The patent modifies the gel layer properties by changing the cellulose ether substitution parameters (s23/s26 ≤ 0.31, MS 0.05-1.00). These changes create a gel layer that forms rapidly enough to prevent disintegration but has extended dissolution characteristics due to the specific hydroxyalkyl substitution pattern, thereby achieving both structural integrity and prolonged release duration.
Solution Approach 2:
The patent creates local quality differences within the gel layer through the specific substitution pattern of cellulose ether. The s23/s26 ratio ≤ 0.31 creates regions with different hydration and dissolution rates, allowing the outer gel layer to provide structural protection while inner regions maintain sustained release capability, thus resolving the contradiction between integrity and duration.
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
This approach extends the release of active ingredients into an aqueous environment, maintaining controlled drug delivery over an extended period without substantial disintegration of the dosage form, allowing for a prolonged and consistent release of the active ingredient.
Implementation Method 1
Water-soluble cellulose ethers hydrate on the outer tablet skin to form a gel layer
Implementation Method 2
Water-soluble cellulose ethers hydrate on the outer tablet skin to form a gel layer
Implementation Method 3
it controls the penetration of additional water into the tablet... control drug diffusion
Data Source
AI summary
A sustained release dosage form comprises an active ingredient blended with a polymeric matrix. At least a portion of the polymeric matrix is formed by a cellulose ether having an onset dissolution temperature of at least 40° C., having anhydroglucose units joined by 1-4 linkages and having methyl groups, hydroxyalkyl groups, and optionally alkyl groups being different from methyl as substituents such that the cellulose ether has an MS (hydroxyalkyl) of 0.05 to 1.00, and hydroxyl groups of anhydroglucose units are substituted with methyl groups such that [s23/s26−0.2*MS(hydroxyalkyl)] is 0.31 or less, wherein s23 is the molar fraction of anhydroglucose units wherein only the two hydroxyl groups in the 2- and 3-positions of the anhydroglucose unit are substituted with a methyl group and wherein s26 is the molar fraction of anhydroglucose units wherein only the two hydroxyl groups in the 2- and 6-positions of the anhydroglucose unit are substituted with a methyl group.