Enteric Coating for Softgel Capsules

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Solution Overview

Problem

Existing enteric coatings for softgel capsules are prone to brittleness, cracking, and stickiness, which affects their handling and stability, especially for capsules with unfavorable geometries, and current polymers have limitations such as inconsistent quality, instability under storage conditions, and adverse effects on dissolution characteristics.

Innovation Solution

An enteric coating formulation comprising controlled release polymers like EUDRAGIT L30-D55, with specific concentrations of glidants like glyceryl monostearate and emulsifiers like polysorbate 80, along with plasticizers like triethyl citrate, which provides flexibility and prevents tackiness, ensuring stable and effective enteric release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional enteric coatings are applied to softgel capsules, then enteric release is achieved, but the coating becomes brittle and cracks during handling

Engineering Contradiction:
Improveenteric release functionVSAvoidcoating flexibility
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent modifies the physical-chemical parameters of the coating system by incorporating plasticizers (triethyl citrate, dibutyl sebacate) in specific concentrations (1-10% w/w) to change the mechanical properties of the coating film. This resolves the contradiction by making the coating flexible enough to prevent cracking while maintaining enteric release functionality through controlled polymer selection and formulation parameters.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating system combining enteric polymers (methacrylic acid copolymers, cellulose derivatives) with plasticizers, glidants, and emulsifiers. This composite formulation achieves both enteric release properties and mechanical flexibility, resolving the contradiction between functional performance and physical integrity during handling.

Inventive Principle:
Principle #40Composite materials

2Reliability

If enteric coating is applied to softgel capsules, then stomach protection is provided, but the coating becomes sticky and aggregates during storage

Engineering Contradiction:
Improvestomach protection functionVSAvoidcoating stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes formulation parameters including plasticizer concentration (1-10% w/w), glidant concentration (0.1-5% w/w), and emulsifier concentration (0.1-5% w/w) to prevent stickiness while maintaining enteric properties. These parameter adjustments resolve the contradiction by ensuring coating stability during storage without compromising stomach protection functionality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces glidants (glyceryl monostearate, sorbitan monolaurate) and emulsifiers (polysorbate 80, cremophor RL 982) as intermediary substances that prevent coating aggregation and stickiness. These intermediaries maintain coating stability during storage while allowing the enteric polymer to fulfill its stomach protection function.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If existing enteric polymers are used for coating, then enteric release is achieved, but quality inconsistency and instability under storage conditions occur

Engineering Contradiction:
Improveenteric release profileVSAvoidstorage stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent specifies precise concentration ranges for each formulation component (enteric polymer 85-99.8% w/w, plasticizer 1-10% w/w, glidant 0.1-5% w/w, emulsifier 0.1-5% w/w) to ensure consistent quality and storage stability. This parameter control resolves the contradiction by providing reproducible enteric release profiles while maintaining stability under various storage conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent develops a universal coating formulation system that works across different softgel capsule types and geometries. The multi-functional formulation provides enteric release, mechanical flexibility, storage stability, and applicability to various capsule sizes, resolving the contradiction between consistent performance and adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If enteric coating is applied to capsules with unfavorable geometries, then enteric release is provided, but cracking and handling difficulties increase

Engineering Contradiction:
Improveenteric release functionVSAvoidhandling ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent adjusts formulation parameters including plasticizer type and concentration to specifically address the needs of capsules with unfavorable geometries. This parameter optimization resolves the contradiction by providing sufficient flexibility to complex-shaped capsules during handling while maintaining enteric release functionality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies coating formulations with specific local optimizations for different capsule geometries, adjusting plasticizer and emulsifier concentrations based on the specific handling requirements of complex-shaped capsules. This local quality approach resolves the contradiction between maintaining enteric function and improving handling ease for unfavorable geometries.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2911654B1Enteric coating for soft capsule
Publication Date: 2024.06.12 CAPSUGEL BELGIUM NV
  • EP2911654B1 patent drawingFigure 1A~1D
  • EP2911654B1 patent drawingFigure 2A~2C

AI summary

The present disclosure relates to a novel aqueous coating composition comprising a polymer, at least one glidant, and at least one emulsifier, and at least one plasticizer, for soft capsule shells or softgel capsules, providing an enteric release profile, and to a method of enteric coating of soft capsule shells or containers; and to the resulting enteric coated soft capsule shells or softgel capsules with the aqueous coating composition.