Enteric Coating Composition for Capsule Halves
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Solution Overview
Problem
The existing methods for enteric coating of capsule halves, particularly those made of gelatine or hydroxypropylmethylcellulose, face challenges such as embrittlement, poor adhesion, and the need for additional sealing steps, leading to unsatisfactory coating and high costs, especially in the dipping process.
Innovation Solution
A coating composition comprising a polymer mixture of at least one enteric (meth)acrylate copolymer and an auxiliary, with a solids content greater than 25% by weight and a viscosity of 150 to 1500 mPa·s, allowing for application in the dipping process without organic solvents, ensuring capsule tightness and rapid dissolution in intestinal fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If enteric coating is applied to gelatine capsules from organic solutions, then coating can be achieved, but embrittlement occurs and adhesion is poor
Solution Approach 1:
The patent changes the fundamental parameter of the coating medium from organic solutions to aqueous preparations. This parameter change eliminates the embrittlement and adhesion problems associated with organic solvents while maintaining effective enteric coating properties. The aqueous-based (meth)acrylate copolymer coatings provide reliable adhesion without compromising capsule strength.
Solution Approach 2:
The patent employs a simplified coating process using aqueous preparations that can be applied directly without complex intermediate layers. This approach replaces the multi-step organic coating process with a simpler, more reliable aqueous system that achieves the same functional result with fewer steps and materials.
2Reliability
If intermediate layer is applied to improve adhesion, then coating adhesion improves, but process becomes lengthy and complicated
Solution Approach 1:
The patent merges the coating and sealing functions into a single integrated process. The aqueous (meth)acrylate copolymer coating serves both as the enteric coating layer and as the sealing medium for joining capsule halves, eliminating the need for separate intermediate layers and sealing steps.
Solution Approach 2:
The aqueous (meth)acrylate copolymer preparation serves multiple functions simultaneously: it provides enteric coating protection, ensures adequate adhesion, and acts as the sealing medium for capsule assembly. This multi-functional approach simplifies the overall process while maintaining all necessary functions.
3Object-affected harmful factors
If gelatine capsules are coated from aqueous preparations, then toxicological safety improves, but processing time increases and costs rise
Solution Approach 1:
The patent changes the coating material from gelatine to (meth)acrylate copolymers in aqueous preparation. This parameter change maintains the toxicological safety benefits of aqueous coating while significantly reducing processing time through the material's inherent properties and simplified application process.
Solution Approach 2:
The patent employs a streamlined coating process using aqueous (meth)acrylate copolymer preparations that require minimal processing steps and drying time. This approach reduces both time and cost compared to traditional gelatine coating methods while maintaining safety standards.
4Reliability
If capsule halves are sealed manually with gelatine solution, then capsule tightness is achieved, but additional processing steps are required
Solution Approach 1:
The patent combines the coating and sealing operations into a single integrated process. The aqueous (meth)acrylate copolymer coating is applied to capsule halves and simultaneously serves as the sealing medium when halves are joined, eliminating separate manual sealing steps and improving productivity.
Solution Approach 2:
The aqueous (meth)acrylate copolymer preparation functions both as the enteric coating material and as the sealing adhesive. This dual functionality eliminates the need for separate sealing materials and steps, streamlining the manufacturing process while ensuring capsule tightness.
5Ease of operation
If dipping process is used for enteric coating of capsules, then coating application is simplified, but coating uniformity and enteric properties become unsatisfactory
Solution Approach 1:
The patent optimizes the viscosity parameter of the aqueous (meth)acrylate copolymer coating composition to enable successful dip coating. By adjusting the viscosity within a specific range, the coating achieves both ease of application through dipping and satisfactory uniformity and enteric properties, resolving the contradiction between application simplicity and coating quality.
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 solution provides a uniform, elastic enteric coating that prevents gastric fluid penetration, eliminates the need for additional sealing, and ensures complete dissolution in intestinal fluid within 30 minutes, while maintaining capsule integrity and efficiency in the dipping process.
Implementation Method 1
The invention relates to a coating composition for the enteric coating of capsule halves made of water-soluble or water-swellable polymer material in the dipping process
Data Source
AI summary
A coating composition for the enteric coating of capsule halves made of water-soluble or water-swellable polymer material in a dipping process is provided. The composition is an aqueous dispersion or solution, containing a polymer mixture of at least one first (meth)acrylate copolymer, which is enteric, and at least one further (meth)acrylate copolymer, which is enteric or water-insoluble, and also auxiliaries which influence the viscosity of the dispersion and the elasticity of the dried polymer film. The solids content of the dispersion or solution is more than 25% by weight and the viscosity is 150 to 1500 mPa·s and a dried film produced from the dispersion or solution has an elongation at break of at least 200%. Also provided is a capsule composed of two capsule halves coated with the dispersion or solution in a dipping process does. The enteric capsule does not dissolve in 0.1 N HCl at pH 1.2 after two hours, but completely dissolves in buffer at pH 6.8 in less than 30 minutes. A method to prepare enteric coated capsule halves is also provided.