DOTAP Chloride Crystallization for Stability
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Solution Overview
Problem
Current amorphous forms of DOTAP chloride are unstable, difficult to prepare in high purity, and sensitive to oxidation, making them unsuitable for pharmaceutical applications due to limited shelf life and handling challenges.
Innovation Solution
A process for preparing crystalline forms of racemic and enantiomerically pure DOTAP chloride using an aprotic medium, such as ketones or ethers, with slow cooling to achieve high purity and stability, reducing hygroscopicity and oxidation sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous forms of DOTAP chloride are used, then they can be prepared relatively easily, but they exhibit poor stability, limited shelf life, and high sensitivity to oxidation
Solution Approach 1:
The patent applies phase transition by transforming DOTAP chloride from amorphous form to crystalline form. The crystallization process involves dissolving the amorphous DOTAP chloride in a suitable solvent and slowly cooling the solution to form stable crystals. This phase transition resolves the contradiction by providing a form that maintains ease of manufacture through straightforward crystallization while achieving superior stability and shelf life.
Solution Approach 2:
The patent utilizes parameter changes by modifying the physical state of DOTAP chloride from amorphous to crystalline through controlled crystallization conditions. By changing parameters such as temperature, solvent composition, and cooling rate, the patent achieves a stable crystalline form that overcomes the instability and oxidation sensitivity of the amorphous form while remaining manufacturable.
2Ease of manufacture
If amorphous forms of DOTAP chloride are used, then they can be obtained without complex processing, but they are difficult to prepare in high purity and have poor handling properties
Solution Approach 1:
The crystallization process employed in the patent uses phase transition from dissolved state to crystalline solid to achieve high purity. The slow cooling method allows impurities to remain in the mother liquor while pure crystals form, naturally separating the product from contaminants without requiring complex purification steps.
Solution Approach 2:
The patent applies extraction by using solvent-based crystallization to separate pure DOTAP chloride crystals from impurities. The impurities remain dissolved in the solvent (mother liquor) while the pure compound crystallizes out, effectively extracting the pure product from the mixture through the crystallization process.
3Ease of manufacture
If amorphous forms of DOTAP chloride are used, then no special processing is required, but they are highly hygroscopic and sensitive to oxidation
Solution Approach 1:
The patent uses phase transition to crystalline form to reduce the surface area and reactivity of DOTAP chloride. The crystalline structure provides a more stable, less reactive form that is less susceptible to oxidation and hygroscopicity compared to the amorphous form, while the crystallization process itself is straightforward and does not require complex processing.
Solution Approach 2:
The patent employs inert atmosphere techniques during the crystallization and storage of DOTAP chloride to protect against oxidation. By conducting the crystallization process and storing the final product in an inert atmosphere (such as nitrogen or argon), the patent prevents contact with oxygen and moisture, thereby eliminating oxidation sensitivity while maintaining ease of manufacture.
4Ease of manufacture
If amorphous forms of DOTAP chloride are used, then they can be obtained directly from synthesis, but they have limited shelf life and are unsuitable for pharmaceutical applications
Solution Approach 1:
The patent applies phase transition by crystallizing DOTAP chloride from its amorphous synthesis product. The crystallization process transforms the unstable amorphous material into stable crystals with defined melting points and characteristic X-ray diffraction patterns. This phase transition extends the shelf life significantly, making the compound suitable for pharmaceutical storage and application while maintaining direct obtainability through a simple one-step crystallization process.
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 forms exhibit >95% purity, >99% stability at room temperature, and excellent handling properties, suitable for long-term storage and use in pharmaceutical formulations.
Implementation Method 1
DOTAP can amongst others build liposomes and other lipidic vesicular aggregates. Liposomes are synthetic multilayered vesicles (spherically self-contained membranes) comprising ambiphilic substances
Implementation Method 2
A process for preparing crystalline forms of racemic and enantiomerically pure DOTAP chloride using an aprotic medium, such as ketones or ethers, with slow cooling to achieve high purity and stability
Data Source
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AI summary
The present invention relates to crystal modifications of racemic (2R,S)- and enantiomerically pure (2R)- resp. (2S)-DOTAP chloride, to processes for the preparation thereof, and to the use thereof for the preparation of pharmaceutical compositions.