Crosslinked Poly(Allylamine) Polymer Purity and Stability Control
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Solution Overview
Problem
Existing crosslinked poly(allylamine) polymers used for treating metabolic conditions suffer from undesirable impurities and stability issues due to incomplete incorporation of diallylamine or multiallylamines, leading to unsaturated substituents that generate allylamine and related impurities during processing and storage.
Innovation Solution
A process is developed to improve polymerization efficiency by optimizing the concentration of 2-propen-1-ylamine and 1,3-bis(allylamino)propane, reducing reaction temperature, and increasing initiator concentration, resulting in a crosslinked poly(allylamine) polymer with reduced residual allyl groups and improved stability, which is then further crosslinked in a specific solvent system to minimize impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If simultaneous polymerization of allylamine and crosslinking with diallylamine is used, then crosslinked poly(allylamine) polymer is formed, but incomplete incorporation of diallylamine leads to unsaturated substituents that generate allylamine impurities during storage
Solution Approach 1:
The patent optimizes the molar ratio of allylamine to diallylamine from the conventional range to a specific range of 4:1 to 12:1, and controls the reaction temperature at 60-80°C to improve polymerization completeness and reduce residual unsaturated groups that generate impurities
Solution Approach 2:
The patent adds a chain transfer agent (such as mercaptan compounds) before polymerization to control the polymerization process and reduce chain termination, thereby improving the incorporation efficiency of diallylamine and reducing unsaturated substituents that would otherwise generate allylamine impurities during storage
2Productivity
If concentration of 2-propen-1-ylamine and 1,3-bis(allylamino)propane is increased, then polymerization efficiency improves, but residual allyl groups may increase if not optimized
Solution Approach 1:
The patent specifies optimal concentration ranges for 2-propen-1-ylamine (0.5-2.0 M) and 1,3-bis(allylamino)propane (0.1-0.5 M), along with optimal molar ratios, to achieve high polymerization efficiency while ensuring complete incorporation of crosslinking agents to prevent residual allyl groups
3Reliability
If reaction temperature is reduced, then propagation is favored over termination, but reaction rate decreases
Solution Approach 1:
The patent optimizes the reaction temperature to a specific range of 60-80°C, which is lower than conventional temperatures to favor propagation over termination and improve polymerization control, while still maintaining an acceptable reaction rate through optimized initiator concentration and monomer ratios
4Productivity
If initiator concentration is increased, then polymerization rate increases, but chain termination may increase reducing efficiency
Solution Approach 1:
The patent optimizes the initiator concentration to a specific range (0.01-0.05 M) to achieve high polymerization rates while minimizing chain termination events, thereby maintaining high polymerization efficiency and reducing residual unsaturated groups
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 improved process yields a crosslinked poly(allylamine) polymer with enhanced purity and stability, suitable for therapeutic applications, particularly in treating metabolic acidosis and chronic kidney disease, by minimizing allylamine formation and maintaining stability over time.
Implementation Method 1
a concurrent polymerization and crosslinking reaction mixture comprising 2-propen-1-ylamine, or a salt thereof, 1,3-bis(allylamino)propane, or a salt thereof, a radical polymerization initiator
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
Pharmaceutical compositions for and methods of treating an animal, including a human, and methods of preparing such compositions. The pharmaceutical compositions contain crosslinked amine polymers and may be used, for example, to treat diseases or other metabolic conditions in which removal of a target species from the gastrointestinal tract would provide physiological benefits.