Enteric Hard Capsule Shell Formation via Thermal Gelation
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Solution Overview
Problem
Existing methods for preparing enteric hard capsules face challenges such as instability in gastric juice, potential stomach irritation, and high production costs due to the need for additional coating processes, which have hindered the commercialization of high-quality and industrially productive enteric capsules.
Innovation Solution
A method involving an aqueous composition with an enteric base material, a capsule forming aid, and a neutralizing agent is used, where the composition is heated, cooled, and then applied to a mold pin at specific temperatures to form a capsule shell, allowing for controlled gelation and drying to create enteric hard capsules that maintain stability in gastric juice and disintegrate in intestinal juice.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capsules are coated with an enteric base material using conventional methods, then enteric properties are achieved, but production costs increase and additional coating processes are required
Solution Approach 1:
The invention merges the capsule shell formation and enteric coating into a single integrated process. The enteric base material is incorporated directly into the capsule shell composition during the gelation process, eliminating the need for separate coating operations while achieving both structural integrity and enteric properties simultaneously
Solution Approach 2:
The capsule shell material serves multiple functions: it provides the structural framework of the capsule, acts as the enteric coating layer, and controls the dissolution behavior. This multi-functional design eliminates the need for separate enteric coating materials and processes, reducing production complexity and cost
2Reliability
If capsules are coated with an enteric base material, then enteric properties are achieved, but production time increases due to additional coating processes
Solution Approach 1:
The capsule shell formation and enteric coating operations are merged into a single gelation process. The aqueous composition containing enteric base material is applied to the mold pin and gelated in one step, producing capsules with integrated enteric properties without requiring sequential coating steps, thereby significantly reducing production time
Solution Approach 2:
The enteric base material is pre-mixed into the capsule shell forming composition before the gelation process begins. This preliminary incorporation ensures that the enteric coating is already present on the capsule shell during formation, eliminating the need for subsequent coating operations and reducing overall production time
3Productivity
If gelatin capsules are used, then high industrial productivity is achieved, but concerns about mad cow diseases and moisture-related deterioration limit their use
Solution Approach 1:
The invention changes the base material from animal-derived gelatin to plant-based HPMC, fundamentally altering the material source and composition parameters. This substitution eliminates safety concerns associated with gelatin while maintaining the gelation properties and industrial manufacturability needed for high productivity
Solution Approach 2:
The invention uses a composite aqueous composition containing HPMC as the base material, enteric base materials (such as cellulose esters), and various additives. This composite formulation combines the advantages of plant-based materials with controlled gelation properties and enteric functionality, achieving both safety and productivity goals
4Reliability
If HPMC capsules are prepared without gelatin, then safety concerns are addressed, but additional processing steps are required to achieve enteric properties
Solution Approach 1:
The invention combines the capsule shell forming process and enteric coating process into a single integrated gelation operation. The enteric base material is incorporated into the HPMC solution before gelation, allowing simultaneous formation of the capsule shell and enteric layer in one step, thereby reducing process complexity despite using plant-based materials
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 method enables the production of high-quality enteric hard capsules that resist gastric juice for 2-4 hours and rapidly disintegrate in intestinal juice, achieving similar characteristics to conventional methods while being suitable for large-scale commercial production.
Implementation Method 1
heating the aqueous composition to a first temperature that is higher than a gelation start temperature of the aqueous composition
Implementation Method 2
A high-temperature mold pin is immersed in an HPMC solution maintained at a temperature higher than or equal to room temperature so as to be coated with the HPMC solution, and HPMC of the HPMC solution coated on the mold pin is gelated by the heat of the mold pin
Implementation Method 3
drying the fixed film at a fifth temperature for a second time period to obtain a capsule shell
Data Source
Figure 1~3
Figure 4
AI summary
A method of preparing enteric hard capsules, and an enteric hard capsule prepared by the method. The method may include: dissolving an enteric base material, a capsule forming aid, and a neutralizing agent in water at room temperature to prepare an aqueous composition; heating the aqueous composition to a first temperature that is higher than a gelation start temperature of the aqueous composition; cooling the heated aqueous composition to a second temperature that is lower than the gelation start temperature; immersing a mold pin heated to a third temperature that is higher than the gelation start temperature into the aqueous composition; removing the mold pin from the aqueous composition to obtain a film coated on the mold pin; maintaining the film on the mold pin at a fourth temperature that is higher than the gelation start temperature for a first time period to fix the film onto the mold pin; and drying the fixed film at a fifth temperature for a second time period to obtain a capsule shell.