Pharmaceutical Coating Agent Using Swelling Clay Labyrinth for Gas Barrier
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Solution Overview
Problem
Conventional methods for imparting gas barrier properties to pharmaceutical solid preparations are either time-consuming, result in large thickness, or compromise disintegration properties, and most fail to achieve permeability levels equivalent to PTP sheets, while also being prone to odor and color changes due to volatile drug decomposition.
Innovation Solution
A coating agent comprising polyethylene glycol and swelling clay in a specific mass ratio, with the clay dispersed in a swollen state to form a belt-like laminated structure, providing a labyrinth effect that imparts excellent gas barrier properties without affecting disintegration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sugar-coating method is used to improve gas barrier properties, then water vapor permeability is reduced, but coating time is extended and preparation size is enlarged
Solution Approach 1:
The invention changes the material parameters by using polyvinyl alcohol copolymer with specific composition (containing vinylidene carbonate units) instead of traditional sugar coating materials. This parameter change enables achieving gas barrier properties with much thinner and faster-drying coatings, resolving the time contradiction.
Solution Approach 2:
The invention uses a composite coating material consisting of polyvinyl alcohol copolymer and inorganic particles (such as silicon oxide or titanium oxide). This composite structure provides both the film-forming capability of the polymer and the gas barrier properties of the inorganic particles, achieving effective gas barrier with reduced coating thickness and time.
2Reliability
If film-coating with polymeric substance is used to improve gas barrier properties, then water vapor permeability is reduced, but coating thickness increases
Solution Approach 1:
The invention creates a thin film coating using polyvinyl alcohol copolymer that is flexible yet effective as a gas barrier. The copolymer structure enables forming sufficiently thin films that provide gas barrier properties without the need for thick coatings, thus reducing the length parameter of the coating.
Solution Approach 2:
The coating incorporates inorganic particles that create a porous or laminated structure within the polymer matrix. This structure provides tortuous paths for gas molecules, enhancing barrier properties while maintaining thin film thickness, thereby resolving the contradiction between thickness and barrier effectiveness.
3Reliability
If conventional film-coating methods are used, then gas barrier properties are improved, but disintegration properties are compromised
Solution Approach 1:
The invention changes the chemical composition parameters of the coating polymer to polyvinyl alcohol copolymer with specific functional groups that provide both gas barrier capability and disintegration functionality. The copolymer structure allows the coating to maintain integrity as a barrier while being capable of disintegrating under appropriate conditions, resolving the stability contradiction.
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 coating agent effectively imparts gas barrier properties equivalent to PTP sheets, preventing drug degradation and odor/color changes, while maintaining rapid disintegration and stability of pharmaceuticals, even when unpackaged.
Implementation Method 1
the swelling clay is uniformly dispersed in the form of a belt-like laminated structure in a film formed by the coating agent, the ratio of the swelling clay in a film formed by the coating agent is not less than 20%
Data Source
Figure 1~2-1
Figure 2-2~2-3
Figure 2-4~3
AI summary
An object of the present invention is to provide a coating agent for a pharmaceutical solid preparation, which imparts an unpackaged pharmaceutical solid preparation with excellent barrier properties equivalent to those of a PTP sheet without affecting the disintegration properties of the pharmaceutical solid preparation. Provided is a coating agent for a pharmaceutical solid preparation which comprises a polyethylene glycol having an average molecular weight of 950 to 25,000 and a swelling clay, wherein the mass ratio of the polyethylene glycol and the swelling clay is 2:8 to 6:4.