Liquid Core Microcapsules with Self-Microemulsifying Systems

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Solution Overview

Problem

Current methods are inadequate for formulating self-microemulsifying systems and microemulsions into solid dosage forms, as they are limited to liquid formulations and lack effective methods for incorporating high drug loadings into microcapsules with a liquid core, leading to instability and low active ingredient incorporation.

Innovation Solution

Microcapsules with a liquid core incorporating a self-microemulsifying system or microemulsion, where a gelling agent is added to promote shell solidification upon contact with the shell phase, allowing for higher drug loadings and improved stability, using a vibrating nozzle method for production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional emulsion preparation methods are used, then liquid phases can be dispersed, but the systems are thermodynamically unstable and quickly separate

Engineering Contradiction:
Improveemulsion stabilityVSAvoidseparation time
Core Design Contradiction:
Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The patent transforms the unstable emulsion system into a stable microemulsion system by changing key parameters: reducing droplet size to nanometer scale (10-100 nm), achieving thermodynamic stability through proper surfactant/co-surfactant selection, and creating isotropic transparent mixtures. This resolves the contradiction by fundamentally altering the system parameters rather than attempting to stabilize the original emulsion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces surfactants and co-surfactants as intermediary substances that mediate between the immiscible oil and water phases. These intermediaries reduce interfacial tension and enable the formation of stable microemulsions, preventing phase separation while maintaining thermodynamic stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If microemulsions are used to increase drug solubilization capacity, then bioavailability improves, but the systems require specific surfactant and co-surfactant combinations that complicate formulation

Engineering Contradiction:
Improvedrug solubilization capacityVSAvoidformulation complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent systematically optimizes the surfactant-to-co-surfactant ratio and HLB values to achieve maximum drug solubilization capacity. By changing these parameters and establishing optimal ranges, the formulation achieves high drug loading while maintaining manageable complexity through standardized selection criteria.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent combines multiple surfactants and co-surfactants with specific HLB values to create composite surfactant systems. This composite approach allows tuning of the overall HLB value to match the drug's solubility requirements, achieving high solubilization capacity while providing a systematic method for formulation development.

Inventive Principle:
Principle #40Composite materials

3Speed

If self-microemulsifying systems are used for solid dosage forms, then drug dissolution and absorption are enhanced, but current methods are limited to liquid formulations

Engineering Contradiction:
Improvedrug dissolution speedVSAvoiddosage form versatility
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The patent segments the self-microemulsifying system into discrete microcapsules with controlled size and composition. This segmentation allows the liquid SMES to be incorporated into solid dosage forms like tablets and capsules, providing versatility in dosage form while preserving the fast dissolution characteristics of the microemulsion system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes phase transition principles by incorporating the liquid SMES into solid dosage forms through techniques like spray drying, freeze drying, or encapsulation. The system transitions from liquid to solid state for storage and administration, then reverts to liquid microemulsion phase in the gastrointestinal tract, achieving both solid dosage form versatility and rapid dissolution.

Inventive Principle:
Principle #36Phase transitions

4Quantity of substance

If high drug loadings are incorporated into microcapsules, then dosage efficiency improves, but active ingredient loss during preparation increases

Engineering Contradiction:
Improvedrug loadingVSAvoidactive ingredient loss
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent performs preliminary optimization of the surfactant-co-surfactant-drug complex formation before microcapsule preparation. By pre-forming stable microemulsion complexes with high drug loading, the system minimizes active ingredient loss during subsequent processing steps, as the drug is already stabilized in the microemulsion phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical mixing and high-shear processing with gentle microemulsion formation processes. The self-assembly nature of microemulsion formation minimizes mechanical stress and prevents active ingredient degradation or loss, enabling high drug loadings to be achieved with minimal loss during preparation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enables the formulation of solid dosage forms with higher active ingredient incorporation and stability, overcoming limitations of existing methods by ensuring proper shell hardening and reducing active ingredient loss during preparation.

Implementation Method 1

wherein a gelling agent is added to promote shell solidification upon contact with the shell phase

Methodology Applied
Scientific EffectGelation: Gel

Implementation Method 2

Self-microemulsifying systems (SMES) are systems consisting of a mixture of an oily (lipophilic) phase comprising at least one lipophilic substance with one or more surface active substance (surfactant, co-surfactant), which spontaneously form microemulsions upon contact with aqueous media

Methodology Applied
Scientific EffectSelf-microemulsification: Microemulsion

Implementation Method 3

using a vibrating nozzle method for production

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP2282722B1Self-microemulsifying systems incorporated into liquid core microcapsules
Publication Date: 2017.05.17 LEK PHARMA D D

AI summary

The invention provides a microcapsule having a shell and a liquid core incorporating a self-microemulsifying system or a microemulsion, wherein the core comprises a lipophilic substance, at least one surfactant, an active agent, a gelling agent and optionally a cosolvent. Furthermore, a method for producing such microcapsules and pharmaceutical formulations comprising such microcapsules is provided.