Pullulan-Gellan Capsule Membrane for Humidity Stability

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Solution Overview

Problem

Current hollow capsules, particularly those made from pullulan polysaccharide, suffer from poor storage stability, dehydration, brittleness, and sensitivity to humidity, as well as disintegration issues due to alkali metal ions, which limits their application and requires strict storage conditions.

Innovation Solution

A membrane-forming compound comprising pullulan polysaccharide, gellan gum, methylglycine-proline, and an anti-hygroscopic agent like stearic acid, which gelates without alkali metal ions, maintains moisture, and improves stability under high humidity, enhancing the properties of both hard and soft capsules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If pullulan polysaccharide capsules are made using conventional methods with alkali metal ions, then gelation occurs, but disintegration is influenced and storage stability deteriorates

Engineering Contradiction:
Improvestorage stabilityVSAvoiddisintegration performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The invention removes alkali metal ions from the capsule formulation entirely, extracting the problematic component that caused both disintegration issues and storage instability. The gelation process is achieved through alternative mechanisms using purified water and natural gelating agents, eliminating the need for alkali metal ion additives.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses composite materials consisting of pullulan polysaccharide combined with natural gelating agents (such as calcium ions from food-grade sources or enzymatic crosslinking agents) to achieve gelation without alkali metal ions. This composite approach maintains both disintegration performance and storage stability.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If pullulan polysaccharide capsules are stored in high humidity environment, then moisture absorption increases, but capsule softness increases and stability decreases

Engineering Contradiction:
Improvehumidity resistanceVSAvoidcapsule stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The invention introduces hydrophobic modifiers as intermediary substances that form a protective barrier between the pullulan polysaccharide matrix and the humid environment. These modifiers (such as fatty acid esters or silane compounds) mediate the interaction by repelling water molecules while maintaining the structural integrity of the capsule.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the hydrophilic-hydrophobic balance parameter of the capsule material by incorporating hydrophobic groups into the pullulan polysaccharide structure. This parameter change reduces the material's affinity for water, thereby improving humidity resistance while maintaining stability.

Inventive Principle:
Principle #35Parameter changes

3Strength

If pullulan polysaccharide capsules are dehydrated during storage, then brittleness increases, but moisture retention becomes difficult

Engineering Contradiction:
Improvemechanical strengthVSAvoidmoisture loss
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention optimizes the plasticizer content and type to change the glass transition temperature and moisture absorption characteristics of the capsule material. By selecting plasticizers with appropriate molecular weight and polarity (such as glycerol or sorbitol at optimized concentrations), the material maintains adequate flexibility and moisture retention without becoming brittle.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure combining pullulan polysaccharide with moisture-retaining agents (such as hygroscopic polymers or lipid components) that form a moisture reservoir within the capsule wall. This composite material simultaneously provides mechanical strength and prevents excessive dehydration.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If gelatin is used as main molding gel, then capsule formation is achieved, but oxidation and adhesion occur leading to quality defects

Engineering Contradiction:
Improvecapsule formationVSAvoidoxidation and adhesion
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention extracts gelatin from the formulation, removing the source of oxidation and adhesion problems. Instead, it uses pullulan polysaccharide as the base material, which has inherent resistance to oxidation and adhesion issues, while still allowing for effective capsule formation through alternative gelation mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces gelatin with a composite material system based on pullulan polysaccharide combined with crosslinking agents or gelating additives that provide comparable or superior capsule formation properties without the harmful oxidation and adhesion effects associated with gelatin.

Inventive Principle:
Principle #40Composite 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

The compound provides improved storage stability, reduced moisture absorption, and enhanced antioxidant properties, leading to more stable and durable capsules with better resistance to oxidation and humidity, meeting the demand for natural and effective capsule formulations.

Implementation Method 1

pullulan polysaccharide, gellan gum and methylglycine-proline moisturizing agent... which gelate without alkali metal ions

Methodology Applied
Scientific EffectGelation: Gel

Implementation Method 2

pullulan polysaccharide and gellan gum... gelate... good interactions between the components of the compound

Methodology Applied
Scientific EffectHydrogen bonding:

Implementation Method 3

methylglycine-proline moisturizing agent... retain moisture during long time storage

Methodology Applied
Scientific EffectHygroscopy:

Implementation Method 4

anti-hygroscopic agent like stearic acid... stay water non-absorbing under the environment of high humidity

Methodology Applied
Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 5

enhanced antioxidant properties, leading to more stable and durable capsules with better resistance to oxidation and humidity

Methodology Applied
Scientific EffectOxidation resistance: Oxidation

Data Source

PatentUS10350568B2Membrane-forming composition, soft and hard capsules prepared based on this composition and the preparation methods
Publication Date: 2019.07.16 JIANGSU LEFAN CAPSULE

AI summary

A membrane-forming composition, soft and hard capsules prepared based on the composition and the preparation methods are described. The membrane-forming composition includes pullulan polysaccharide, gellan gum, amino acid moisturizing agent, anti-hygroscopic agent and so on. It is suitable for the fabrication of hard or soft capsules. The membrane-forming composition can gelate without alkali metal ions. It has a high moisture retention rate which makes it not easy to take up moisture and turn soft in high humid environment, and it will not turn yellow during long time storage. Furthermore, the membrane-forming composition is made up of pure natural materials.