Resorbable Polymer Purification via Critical Concentration Precipitation
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Solution Overview
Problem
Existing methods for purifying resorbable polymers, such as poly(D,L-lactide) and D,L-lactide-glycolide copolymers, result in unacceptably high residual monomer content, which is problematic for medical and pharmaceutical applications due to potential side effects, interference with active ingredients, and impact on mechanical strength and degradation.
Innovation Solution
A method involving the precipitation of polymers in a mixing chamber with a solvent and precipitation agent, where the polymer concentration is optimized around the critical concentration (C crit ± 0.3 logarithmic units, using solvents like acetone and precipitation agents like water, to effectively separate residual monomers, achieving a residual monomer content below detection limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional purification methods are used, then the polymer can be obtained, but the residual monomer content remains unacceptably high
Solution Approach 1:
The patent applies parameter changes by optimizing the polymer concentration in the solution to be at or close to the critical concentration (Ccrit). This specific parameter adjustment enables significantly more effective separation of residual monomers during precipitation, reducing monomer content to below detection limits while maintaining a feasible purification process
Solution Approach 2:
The patent employs dynamic control of the precipitation process by carefully managing the addition rate of the polymer solution to the precipitation agent and controlling mixing conditions. This dynamic approach ensures optimal separation efficiency at the critical concentration point, achieving ultra-low residual monomer content without excessive process complexity
2Reliability
If residual monomer content is reduced to very low levels, then polymer purity for medical applications is achieved, but process optimization complexity increases
Solution Approach 1:
The patent identifies and controls the critical parameter of polymer concentration at Ccrit, along with other key parameters such as solvent-to-precipitation agent ratio and addition rate. By focusing optimization on these specific parameters, the patent achieves reliable ultra-pure polymer for medical applications while keeping the optimization process manageable rather than excessively complex
Solution Approach 2:
The patent employs feedback control by monitoring the precipitation process conditions and adjusting parameters to maintain optimal separation. This ensures consistent achievement of below-detection-limit residual monomer content while providing a systematic approach to process optimization that prevents unnecessary complexity
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 method significantly reduces residual monomer content in resorbable polymers, making them suitable for medical applications by minimizing side effects and ensuring high purity and mechanical stability.
Implementation Method 1
the polymer solution is added to a precipitation agent in a mechanical dispersion unit. The polymer precipitates and is separated from the slurry comprising said precipitation agent and precipitated polymer
Data Source
AI summary
The invention relates to a method for the purification of a resorbable polymer from residual monomers comprising the addition of a solution of said polymer in a solvent and the addition of a precipitation agent into a mixing chamber to precipitate the polymer, characterized in that the concentration of the polymer in the solution is log Ccrit ± 0.3 logarithmic units, wherein Ccrit is the critical concentration.