Sufentanil Citrate Crystallization in Non-Aqueous Solvent
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The classical method for preparing sufentanil citrate results in oiling out of solution and uncontrolled crystallization, leading to hazardous manual intervention and product aggregation, and the inability to polish and reprocess the product, making it unsuitable for scalable pharmaceutical production.
Innovation Solution
A process involving the formation of sufentanil citrate in a polar non-aqueous solvent, followed by heating and filtering at controlled temperatures to produce crystals with reduced solvent content, allowing for scalable and safe production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sufentanil citrate is prepared by contacting sufentanil base with citric acid in water with charging everything upfront, then the salt formation reaction is simple and direct, but the salt oils out of solution and crystallizes uncontrollably, requiring hazardous manual intervention and making polishing filtration impossible
Solution Approach 1:
The patent changes the solvent parameter from water to a non-aqueous solvent system (ether/alcohol mixture), which fundamentally alters the crystallization behavior of sufentanil citrate. This parameter change prevents the oiling out phenomenon and enables controlled crystallization that can be filtered through polishing filters, directly resolving the contradiction between ease of manufacture and ease of operation
Solution Approach 2:
The patent uses a composite solvent system comprising both ether and alcohol components rather than a single solvent. This composite approach leverages the complementary properties of both solvents to achieve optimal dissolution and crystallization behavior, preventing oiling out while maintaining solubility at reaction temperatures, thus resolving the operational difficulties
2Productivity
If sufentanil citrate crystallizes uncontrolled from aqueous solution, then the reaction proceeds to completion, but the product solidifies into chunks requiring milling and sieving, creating safety hazards and exposure issues
Solution Approach 1:
By changing from aqueous to non-aqueous solvent system, the patent modifies the crystallization kinetics and morphology. The product forms as filterable crystals rather than aggregated chunks, eliminating the need for milling operations and associated safety hazards while maintaining complete reaction conversion
Solution Approach 2:
The patent replaces the mechanical milling and sieving process with a filtration process. The controlled crystallization in non-aqueous solvent produces crystals of appropriate size and morphology that can be separated by filtration alone, eliminating hazardous mechanical operations
3Ease of manufacture
If sufentanil citrate is prepared in aqueous solution, then the reaction is straightforward, but single step reprocessing is not possible since the material does not redissolve in the matrix
Solution Approach 1:
The use of non-aqueous solvent creates a reaction matrix in which the sufentanil citrate product has limited solubility at low temperatures but complete solubility at elevated temperatures. This enables the entire reaction mixture to be redissolved by heating and reprocessed in a single step, providing versatility while maintaining manufacturing simplicity
4Quantity of substance
If sufentanil citrate crystallizes from aqueous solution, then the product is obtained, but polishing sterile filtration is not possible due to aggregated product formation
Solution Approach 1:
Changing to non-aqueous solvent system produces crystals with different physical characteristics - smaller, more uniform size distribution and better flow properties. These crystals pass through polishing filters efficiently, enabling sterile filtration while maintaining high product yield
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 process enables the production of sufentanil citrate with less than 5000 ppm of polar non-aqueous solvent, facilitating polishing filtration and single-step reprocessing, improving yield and process capabilities.
Implementation Method 1
heating the solution of sufentanil citrate to a temperature from about 40° C. to about 70° C. to form a plurality of crystals of sufentanil citrate
Implementation Method 2
filtering the plurality of crystals of sufentanil citrate at a temperature from about 40° C. to about 60° C. thereby isolating crystals of sufentanil citrate
Data Source
AI summary
Provided herein are processes for forming sufentanil citrate from sufentanil base. One process comprises forming sufentanil citrate in the presence of a polar non-aqueous solvent. Other processes comprise forming sufentanil citrate in the presence of water.