Cellulose Ether Acetate Phthalates Enteric Coating Solubility
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Solution Overview
Problem
Current esterified cellulose ethers used in pharmaceuticals, such as HPMCAP, face challenges with low water solubility at low degrees of neutralization, leading to inadequate protection of drugs from acidic environments and stomach irritation, and require complex organic solvent-based preparation methods.
Innovation Solution
Development of novel cellulose ether acetate phthalates with specific degrees of substitution and neutralization, allowing for water solubility and resistance to acidic environments, enabling their use in capsule shells and dosage form coatings without the need for organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HPMCAP is used with low degree of neutralization to maintain enteric coating properties, then resistance to acidic environment is improved, but water solubility deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the degree of substitution of phthalyl groups (0.05-0.20) and acetyl groups (0.61-0.90) to achieve a balance between water solubility and enteric coating properties. This specific parameter range allows the polymer to dissolve in water while maintaining resistance to acidic environments.
Solution Approach 2:
The invention creates a composite polymer structure combining hydroxypropyl methyl cellulose with phthalyl and acetyl groups. This composite material integrates the water-soluble characteristics of HPMC with the enteric properties of phthalate esters, achieving both required properties simultaneously.
2Quantity of substance
If organic solvents are used to dissolve HPMCAP and drugs for spray-drying, then drug dispersion and solubility improvement are achieved, but process complexity and safety concerns increase
Solution Approach 1:
The patent uses HPMCAP as an intermediary substance that facilitates drug solubility and dispersion without requiring organic solvents. The polymer acts as a hydrophilic mediator that surrounds drug molecules, improving their apparent solubility in aqueous environments through solid dispersion formation.
Solution Approach 2:
The invention changes the physical state and molecular arrangement parameters by forming solid amorphous dispersions. This transforms the drug from a crystalline state to an amorphous state within the polymer matrix, significantly improving solubility and bioavailability without organic solvents.
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 novel cellulose ether acetate phthalates demonstrate enhanced water solubility and resistance to acidic environments, facilitating effective drug protection and bioavailability while eliminating the complexity of organic solvent use in their preparation.
Implementation Method 1
The novel cellulose ether acetate phthalates demonstrate enhanced water solubility
Data Source
AI summary
A cellulose ether acetate phthalate is provided, wherein the degree of substitution of phthalyl groups is from 0.02 to 0.25, the degree of neutralization of phthalyl groups is not more than 0.5, the degree of substitution of acetyl groups is from 0.02 to 0.40, and the total degree of substitution of phthalyl and acetyl groups is not more than 0.50. The cellulose ether acetate phthalate has a solubility in water of at least 2.0 weight percent at 2 °C.