Solifenacin Succinate Crystallization via Controlled Seeding
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Solution Overview
Problem
Current methods for crystallizing solifenacin succinate fail to achieve high purity and controlled average particle size with a mono-modal particle size distribution, leading to agglomeration and unwanted nucleation issues, which are critical for efficient pharmaceutical formulation.
Innovation Solution
A crystallization process using a solvent mixture of C5-C10 alcohols, preferably n-pentanol or n-hexanol, with controlled seeding temperature and aging to manage nucleation and crystal growth, allowing for precise control of average particle size and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional crystallization methods are used without controlled seeding, then the crystallization process is simple, but the product exhibits bi- or multi-modal particle size distribution and contains agglomerates
Solution Approach 1:
The patent applies preliminary action by performing controlled seeding at a specific temperature (seeding temperature) before the main crystallization process. Seeds are introduced at this controlled temperature point to initiate crystal formation in a controlled manner, preventing unwanted nucleation and ensuring mono-modal particle size distribution. This preliminary seeding step is crucial for controlling the subsequent crystal growth and avoiding agglomeration.
Solution Approach 2:
The patent employs parameter changes by systematically controlling the seeding temperature and aging time at this temperature. By adjusting these parameters, the process achieves precise control over nucleation and crystal growth. The seeding temperature is optimized to facilitate controlled crystal formation, while the aging period allows for uniform crystal development, resulting in consistent mono-modal particle size distribution.
2Manufacturing precision
If the crystallization process is extended to achieve high purity, then the product purity increases, but the production time increases
Solution Approach 1:
The patent uses preliminary seeding at controlled temperature to accelerate the crystallization process. By introducing seeds at the optimal seeding temperature, the system skips the lengthy induction period of spontaneous nucleation and directly enters the crystal growth phase. This preliminary action significantly reduces the time required to achieve high purity while maintaining product quality.
Solution Approach 2:
The patent implements feedback control by monitoring and adjusting the aging time at seeding temperature. The process allows for controlled crystal growth by maintaining the seeds at the seeding temperature for a specific aging period, then proceeding to cooling. This feedback mechanism ensures that the crystallization process achieves high purity efficiently without excessive time consumption.
3Manufacturing precision
If additional solvent mixture is added to control nucleation, then the particle size control improves, but the process complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the solvent mixture composition and the seeding temperature. Instead of adding multiple different solvents, the process controls the average particle size by adjusting the temperature at which seeds are introduced and the aging time at this temperature. This parameter optimization achieves precise particle size control with a relatively simple solvent 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 process effectively reduces impurities, achieves high purity, and produces solifenacin succinate with a desired one-modal particle size distribution, suitable for large-scale industrial use and pharmaceutical applications.
Implementation Method 1
A solifenacin salt, which is solifenacin succinate, is dissolved in a solvent mixture comprising water and a C5 to C10 alcohol
Implementation Method 2
cooling the dissolved mixture to the seeding temperature Tseeding, which is between 40°C and 80°C
Implementation Method 3
seeding the dissolved mixture with crystals of solifenacin salt
Implementation Method 4
aging the seeded media to additionally control the nucleation process for 10 to 120 minutes
Implementation Method 5
crystallization process for the preparation and/or purification of solifenacin succinate
Implementation Method 6
cooling the mixture to a final temperature between -40 °C and 40 °C
Implementation Method 7
cooling the mixture to a final temperature between -40 °C and 40 °C, preferably to a temperature between 5°C and 10°C
Implementation Method 8
filtering and washing the crystals obtained
Data Source
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AI summary
The invention relates to a preparation and purification processes of solifenacin salts, particularly to a crystallization process of solifenacin succinate, leading to high purity of the obtained product as well as to the desired average particle size and desired modality of the particle size distribution.