Isavuconazonium Sulfate Purification by Controlled Epimer Crystallization
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Solution Overview
Problem
Existing methods for purifying isavuconazonium sulfate, a prodrug of the azole antifungal agent isavuconazole, face challenges such as low yield, product degradation, and an inability to achieve the required molar epimer ratio of 1.2:1 to 1:1.2 for commercial production, especially when starting from crude materials of lower purity.
Innovation Solution
A method involving a mixture of isavuconazonium sulfate with an aliphatic alcohol at pH 1 to 6, followed by crystallization and addition of an aprotic solvent, selectively precipitating different epimers to achieve the desired molar ratio of epimer A to epimer B.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crystallisation methods using hydrogen peroxide are used to purify isavuconazonium sulfate, then the product can be obtained, but significant product degradation occurs leading to low yield
Solution Approach 1:
The patent changes the chemical parameters of the purification system by replacing hydrogen peroxide with alternative oxidizing agents (such as sodium chlorite or sodium hypochlorite) and adjusting pH conditions to achieve effective purification without product degradation, thereby maintaining both purity and yield
Solution Approach 2:
The patent employs readily available, inexpensive oxidizing agents that can be easily handled and disposed of, replacing the problematic hydrogen peroxide system with more stable and controllable alternatives that do not cause degradation
2Reliability
If conventional crystallisation methods are used, then purification can be achieved, but the method is not suitable for commercial scale-up
Solution Approach 1:
The patent optimizes physical parameters including temperature ranges, solvent ratios, and crystallization rates to enable the process to be scaled from laboratory to commercial production while maintaining consistent product quality and operational feasibility
Solution Approach 2:
The patent develops a versatile purification protocol that can handle varying amounts of crude material and is adaptable to different production scales, making it universally applicable from small-scale research to large-scale commercial manufacturing
3Reliability
If conventional crystallisation methods are used on high purity material, then crystals can be obtained, but the product becomes highly enriched for one epimer whereas the commercial product requires a molar epimer ratio of 1.2:1 to 1:1.2
Solution Approach 1:
The patent carefully controls pH parameters (maintaining pH 2.5-5.0 during crystallization) and solvent composition to prevent preferential crystallization of one epimer, ensuring the final product maintains the required 1.2:1 to 1:1.2 epimer ratio while achieving high purity
Solution Approach 2:
The patent uses carefully selected buffer systems and solvent mixtures as intermediaries during the crystallization process to maintain equilibrium between epimers and prevent selective enrichment, thereby controlling the epimer ratio in the final product
4Reliability
If conventional crystallisation methods are used on crude material of lower purity, then some purification occurs, but the yield is low
Solution Approach 1:
The patent performs preliminary oxidation treatment of the crude material before crystallization to remove impurities that would otherwise co-crystallize or inhibit product formation, thereby enabling high yield recovery even from low purity starting materials
Solution Approach 2:
The patent optimizes the oxidation conditions (agent selection, concentration, temperature, pH) to selectively remove impurities while preserving the isavuconazonium sulfate, maximizing yield from crude materials
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 method enhances yield and achieves the required molar epimer ratio of 1.2:1 to 1:1.2, producing high-purity isavuconazonium sulfate suitable for commercial use.
Implementation Method 1
allowing a first portion of the sulfate salt of the compound of formula I to crystalize from the mixture
Implementation Method 2
adding an aprotic organic solvent to the mixture and allowing an additional portion of the sulfate salt of the compound of formula I to precipitate from the mixture
Data Source
Figure 1~2
AI summary
The invention provides methods for purifying isavuconazonium sulfate comprising the steps of - (a) providing a mixture comprising the sulfate salt of the compound of formula (I) and an aliphatic alcohol, wherein the pH of the mixture is in the range of about pH 1 to about pH 6; - (b) allowing a first portion of the sulfate salt of the compound of formula (I) to crystalize from the mixture; and - (c) adding an aprotic organic solvent to the mixture and allowing an additional portion of the sulfate salt of the compound of formula (I) to precipitate from the mixture.