Aqueous Enteric Capsule Films Without Solvents or Thermal Stress
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Solution Overview
Problem
Existing capsule materials for pharmaceutical and nutritional applications are not generally recognized as safe (GRAS) and require complex, solvent-based processes or thermal deformation methods that cause thermal stress, making them unsuitable for delayed or enteric release of actives.
Innovation Solution
Aqueous film-forming compositions using low viscosity alginate and low viscosity film-forming polymers like HPMC, allowing for the production of capsule shells with delayed or enteric release properties without additional gelling agents or multiple coating steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic solvents are used to dissolve the mixed ester of alkylcellulose for capsule preparation, then the capsule can be formed by conventional dipping method, but the process complexity increases and organic solvents are undesirable for pharmaceutical uses
Solution Approach 1:
The patent extracts and removes the organic solvent component from the capsule formulation process. Instead of using organic solvents to dissolve alkylcellulose, the invention uses water-soluble polymers (hydroxypropyl methylcellulose and carboxymethyl cellulose) that can be dissolved in water, thereby eliminating the need for organic solvent handling and processing complexity
Solution Approach 2:
The patent changes the solvent parameter from organic to aqueous. By switching from organic solvents to water as the dissolution medium, the process becomes simpler and safer for pharmaceutical applications while maintaining the capsule formation capability through dip-coating methods
2Ease of manufacture
If plastic deformation at elevated temperature is used to shape capsules, then capsule formation is achieved, but thermal stress and thermal degradation occur
Solution Approach 1:
The patent replaces the thermal-mechanical shaping process with a wet-coating process. Instead of using heat and pressure to deform and shape capsules, the invention uses aqueous polymer solutions that are deposited onto capsule cores and then dried to form the capsule shell, eliminating thermal stress and degradation
Solution Approach 2:
The patent changes the temperature parameter from elevated to ambient. By conducting the capsule formation process at room temperature using water-soluble polymers rather than requiring heat for plastic deformation, the harmful thermal effects are eliminated while capsule shaping is achieved through the coating and drying process
3Reliability
If alginate is used for capsule film formation, then GRAS compliance is achieved, but additional gelling agents and multiple coating steps are required
Solution Approach 1:
The patent merges the functions of multiple polymers (hydroxypropyl methylcellulose and carboxymethyl cellulose) into a single aqueous coating composition. This combination provides both film-forming capability and enteric properties in one step, eliminating the need for separate gelling agents and multiple coating steps while maintaining GRAS compliance
Solution Approach 2:
The patent creates a universal aqueous polymer composition that performs multiple functions simultaneously: it forms the capsule film, provides enteric release properties, and ensures GRAS compliance. This multi-functional coating eliminates the need for additional specialized agents and simplifies the manufacturing process
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
Provides GRAS-compliant capsule shells with improved film strength and enteric performance, enabling efficient delayed or enteric release of actives without the need for organic solvents or complex manufacturing processes.
Implementation Method 1
The blends can also be utilized in coating, micro-encapsulations and other film-forming applications. Alginate is a convenient material for the film part of the capsule because it can be formed in the process of preparing the capsule
Implementation Method 2
Sodium alginate hydrates readily in water, the solutions are stable in the pH range of 4-10 and upon drying form strong transparent films
Data Source
AI summary
The present invention is directed to aqueous film-forming compositions suitable for capsule films, capsule shells, as wells as methods for producing such capsule film, capsule shell and the use thereof.