Crystalline DOPC Stability via Aprotic Crystallization

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Solution Overview

Problem

DOPC is unstable at room temperature, sensitive to oxidation, and difficult to produce in high purity, making it unsuitable for pharmaceutical applications, particularly due to its amorphous and hygroscopic nature, which limits its handling and storage stability.

Innovation Solution

Crystalline forms of DOPC with high chemical purity and stability are achieved through crystallization from an aprotic medium, providing improved handling and storage stability, with a process that includes cooling solutions and seeding to form crystals, and recrystallization of amorphous or semi-crystalline material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If DOPC is stored at room temperature, then it is easily accessible and usable, but it undergoes oxidation and degrades rapidly

Engineering Contradiction:
Improvestorage temperatureVSAvoidstorage stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the physical state parameter of DOPC from amorphous to crystalline form. This parameter change fundamentally alters the stability characteristics, allowing DOPC to be stored at room temperature without oxidation degradation. The crystalline structure creates a more stable, ordered arrangement that resists oxidative attack compared to the disordered amorphous state.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transition by converting DOPC from amorphous phase to crystalline phase through controlled crystallization processes. This phase transition is the key mechanism that enables room temperature storage stability, as the crystalline phase has lower molecular mobility and greater resistance to oxidation compared to the amorphous phase.

Inventive Principle:
Principle #36Phase transitions

2Ease of manufacture

If DOPC is produced in amorphous form, then production is simpler, but purity and handling are severely limited

Engineering Contradiction:
Improveproduction simplicityVSAvoidpurity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the physical state parameter from amorphous to crystalline, which enables purification through crystallization. The crystalline form allows for selective crystallization of pure DOPC from impurities, achieving >98% purity. The ordered crystal lattice structure naturally excludes impurities during the crystallization process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts pure crystalline DOPC from the reaction mixture through crystallization. The crystallization process selectively precipitates pure DOPC crystals while leaving impurities in the mother liquor, enabling effective separation and purification without complex additional steps.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If DOPC is produced in amorphous form, then production is simpler, but handling and storage stability are severely limited

Engineering Contradiction:
Improveproduction simplicityVSAvoidhandling stability
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent changes the physical state from amorphous to crystalline, which fundamentally improves handling properties. Crystalline DOPC has defined melting point, controlled solubility, and predictable physical behavior, making it easy to handle, weigh, and process. The crystalline form also reduces hygroscopicity compared to amorphous forms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful effect of crystallization (which can trap impurities) into a benefit by using it as a purification mechanism. The controlled crystallization process from optimized solvent systems ensures that only pure DOPC crystallizes, while impurities remain dissolved and are removed during filtration.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If oxidation protection is added to DOPC, then stability is improved, but general applicability is severely limited due to interactions with active ingredients

Engineering Contradiction:
Improveoxidation stabilityVSAvoidapplicability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the fundamental parameter of DOPC stability by creating a crystalline form that is inherently resistant to oxidation. This eliminates the need for external oxidation protection agents. The crystalline structure's ordered packing and reduced molecular mobility provide intrinsic protection against oxidative degradation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The crystalline DOPC structure provides self-protection against oxidation through its ordered molecular arrangement. The tight packing in the crystal lattice reduces accessibility of oxygen to the susceptible double bonds, and the reduced molecular mobility slows down oxidation kinetics, making the system self-protecting without external additives.

Inventive Principle:
Principle #25Self-service

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 crystalline DOPC exhibits >98% purity and >99% stability over 12 months at room temperature and >18 months at controlled humidity, with enhanced melting points and reduced water content, making it suitable for pharmaceutical formulations like liposomes and lipoplexes.

Implementation Method 1

Crystalline forms of DOPC with high chemical purity and stability are achieved through crystallization from an aprotic medium

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 2

The crystallization process includes cooling solutions and seeding to form crystals

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 3

The crystalline DOPC exhibits >98% purity and >99% stability over 12 months at room temperature and >18 months at controlled humidity, with enhanced melting points and reduced water content

Methodology Applied
Scientific EffectPhase transition: Phase Change

Data Source

PatentEP2280691B1crystalline DOPC
Publication Date: 2022.08.03 MERCK PATENT GMBH
  • EP2280691B1 patent drawingFigure 1
  • EP2280691B1 patent drawingFigure 2
  • EP2280691B1 patent drawingFigure 3

AI summary

The invention relates to stable crystal modifications of (R,S)-, (R)- and (S)-DOPC, a method for production of these modifications and also use thereof as a component for producing medicaments.