Salcaprozic Acid Purification Using Reagents for Pink Impurity Removal
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Solution Overview
Problem
Existing processes for preparing Salcaprozic Acid and its pharmaceutically acceptable salts often result in the formation of colored impurities, particularly a pink color, which are difficult to remove completely.
Innovation Solution
The use of novel reagents such as benzotriazole, hydrazine, and sodium borohydride during the hydrolysis of 8-(2,4-dioxo-1,3-benzoxazin-3-yl)octanoic acid ethyl ester to produce Salcaprozic Acid, followed by purification steps to eliminate colored impurities, results in a colorless, white solid product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional processes are used for preparing Salcaprozic Acid, then the production is straightforward, but colored impurities (pink color) are formed that are difficult to remove
Solution Approach 1:
The patent applies preliminary action by adding metal complexing agents (EDTA, DTPA) and reducing agents (ascorbic acid, sodium bisulfite, triphenylphosphine) during the hydrolysis step before the colored impurities fully form. This preventive approach eliminates the pink coloration at its source rather than attempting removal afterward, thereby maintaining both process simplicity and product purity.
2Manufacturing precision
If metal complexing agents and reducing agents are used to remove colored impurities, then product purity is improved, but the process complexity increases
Solution Approach 1:
The patent merges multiple functions into a single integrated hydrolysis step. The hydrolysis reaction, metal ion complexation, and reduction of colored impurities all occur simultaneously in one pot without requiring separate purification steps. This combination approach achieves high product purity while avoiding the need for additional equipment or complex multi-step procedures.
Solution Approach 2:
The patent employs reagents that perform multiple functions: EDTA and DTPA serve as both metal complexing agents and stabilizers, while ascorbic acid, sodium bisulfite, and triphenylphosphine act as reducing agents that prevent oxidation-induced coloration. This multi-functionality reduces the number of separate additives and steps needed, simplifying the overall process while maintaining product purity.
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 effectively removes colored impurities, producing Salcaprozic Acid and its salts with minimal absorbance at 400 nm and high transmission at 600 nm, ensuring high purity and visual clarity.
Implementation Method 1
The use of novel reagents such as benzotriazole, hydrazine, and sodium borohydride during the hydrolysis of 8-(2,4-dioxo-1,3-benzoxazin-3-yl)octanoic acid ethyl ester to produce Salcaprozic Acid, followed by purification steps to eliminate colored impurities
Implementation Method 2
hydrolyzing a compound of formula II: wherein, R is straight or branched chain alkyl in the presence of benzotriazole, hydrazine, Sodium borohydride or mixture thereof
Data Source
Figure 1
AI summary
Processes that use novel reagents for the removal of colored impurity during the preparation of Salcaprozic Acid and pharmaceutically acceptable salts thereof. The processes include hydrolysis of 8-(2,4-dioxo-1,3-benzoxazin-3-yl)octanoic acid ethyl ester in the presence of or by contacting it with benzotriazole, hydrazine and/or sodium borohydride.