Non-Gelatin Soft Capsule Shell for Alkaline Stability

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Solution Overview

Problem

Conventional gelatin capsules struggle to encapsulate pharmaceutical agents with high concentrations or alkaline properties, leading to stability issues and limited dosage capabilities, as they are prone to degradation by alkali substances.

Innovation Solution

A non-gelatin encapsulation system using a shell composed of modified starch and gelling carrageenan, which provides high resistance to alkaline fills, allowing for the successful encapsulation of active ingredients with pH levels above 7.5, such as ibuprofen, naproxen, and acetaminophen, in stable and commercially viable softgel forms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If gelatin capsules are used to encapsulate alkaline pharmaceutical agents, then the capsules can be manufactured using conventional processes, but the capsules degrade due to alkali substances leading to instability

Engineering Contradiction:
Improveconventional manufacturing process compatibilityVSAvoidcapsule stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the capsule shell by replacing gelatin with an enteric coating formulation containing polymers such as cellulose acetate phthalate, hydroxypropyl methyl cellulose phthalate, or polyvinyl acetate phthalate. This parameter change allows the capsule to resist alkaline degradation while maintaining manufacturability through adapted conventional processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material formulation for the capsule shell, combining multiple polymers and plasticizers (such as triethyl citrate or dibutyl sebacate) to create an enteric coating that provides both chemical resistance to alkaline substances and appropriate dissolution properties in the gastrointestinal tract.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If gelatin capsules are used with high concentrations of active ingredients, then dosage capability is limited, but stability issues occur due to alkali degradation

Engineering Contradiction:
Improveactive ingredient concentrationVSAvoidcapsule stability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the shell material parameters to enable higher active ingredient concentrations by eliminating the alkali degradation pathway. The enteric coating formulation allows formulation of capsules with elevated levels of basic pharmaceutical agents without compromising structural integrity or stability during storage.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If non-gelatin materials are used to resist alkaline degradation, then capsule stability improves, but manufacturing complexity increases

Engineering Contradiction:
Improvealkaline resistanceVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies enteric coating materials in advance during the capsule manufacturing process, incorporating the protective polymers into the shell formulation before final capsule formation. This preliminary action ensures alkaline resistance is built into the capsule structure itself, eliminating the need for additional post-manufacturing protection steps.

Inventive Principle:
Principle #10Preliminary action

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 system enables the production of softgel capsules with higher active ingredient concentrations than previously possible, maintaining stability and commercial viability, even under accelerated testing conditions, by utilizing a starch/gelling carrageenan combination that resists alkaline degradation.

Implementation Method 1

a non-gelatin soft capsule system comprising a shell made principally of a starch/gelling carrageenan

Methodology Applied
Scientific EffectGel: Gel

Implementation Method 2

which displays the novel and unexpected quality of high resistance to concentrated alkaline fills

Methodology Applied
Scientific EffectChemical resistance:

Data Source

PatentUS8231896B2Non-gelatin soft capsule system
Publication Date: 2012.07.31 R P SCHERER TECH INC

AI summary

A non-gelatin encapsulation system for liquid filled soft capsules, by nature of the carrier, the cationic-ionic balance of the carrier and the active ingredients, or the concentration of the active ingredients and excipients, are difficult or impossible to commercially encapsulate in gelatin capsules. In particular, the system is adapted for the encapsulation of highly basic, or alkaline, fills. The system provides for a predominantly starch and gelling carrageenan based shell, which displays high resistance to both concentrated fills and to alkaline fills, in particular, to those fills which contain the salt or salts of weak acids and strong bases.