Copolymer-1 Synthesis via Infrared-Controlled NCA Polymerization

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Solution Overview

Problem

Existing methods for preparing copolymer-1, such as glatiramer acetate, face inefficiencies in achieving desired molecular weights, which can impact the effectiveness and consistency of the final product.

Innovation Solution

A method involving the polymerization of N-carboxyanhydrides of protected glutamic acid and lysine, with specific protecting groups, using a polymerization initiator, followed by deprotection to obtain copolymer-1, where the molecular weight is monitored and controlled using techniques like infrared probing to terminate the reaction at a desired range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional polymerization methods are used to prepare copolymer-1, then the synthesis process can be completed, but the molecular weight control is imprecise and the reaction efficiency is low

Engineering Contradiction:
Improvemolecular weight controlVSAvoidreaction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent employs real-time monitoring of the polymerization reaction using infrared spectroscopy to track the disappearance of NCA carbonyl peaks. This feedback mechanism allows continuous adjustment of reaction conditions and termination at the optimal point, achieving both precise molecular weight control (20-40 kDa) and high reaction efficiency. The on-line measurement enables dynamic control rather than static batch processing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces conventional off-line molecular weight measurement methods (such as GPC requiring sample removal and analysis) with on-line infrared spectroscopic monitoring. This substitution allows real-time detection of reaction progress through characteristic carbonyl absorption bands, enabling continuous process control without interrupting the polymerization, thereby simultaneously improving precision and productivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If the polymerization reaction is allowed to proceed to completion, then maximum polymer yield is achieved, but the molecular weight becomes uncontrolled and exceeds desired ranges

Engineering Contradiction:
Improvepolymer yieldVSAvoidmolecular weight
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent transforms the static, fixed-duration polymerization process into a dynamic, adaptive process. By continuously monitoring the NCA carbonyl peak intensity via infrared spectroscopy and correlating it with molecular weight through calibration models, the reaction can be terminated at any optimal point. This dynamic control enables achieving desired molecular weights (20-40 kDa) while maintaining high yield, rather than allowing uncontrolled progression to completion.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If protective groups are not used during polymerization, then the process is simpler, but side reactions occur that compromise product purity

Engineering Contradiction:
Improveprocess simplicityVSAvoidproduct purity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary protection of amino acid side chains with orthogonal protecting groups (Boc for lysine, OMe for glutamic acid) before polymerization. These protecting groups prevent unwanted side reactions during the NCA polymerization process. The protection is applied in advance, allowing the main polymerization to proceed cleanly, followed by systematic deprotection steps to yield the final pure copolymer-1 product with controlled structure and high purity.

Inventive Principle:
Principle #10Preliminary action

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 approach allows for the efficient synthesis of copolymer-1 with a desired molecular weight, enhancing the precision and quality of the product, potentially improving its therapeutic efficacy in treating multiple sclerosis.

Implementation Method 1

an infrared (IR) probe to measure the amount of a carbamate moiety (as determined by the intensity of one or more infrared absorption bands characteristic of the carbamate moiety) in the reaction mixture

Methodology Applied
Scientific EffectInfrared absorption: Absorption (EM radiation)

Implementation Method 2

contacted with a polymerization initiator to initiate polymerization of the mixture of N-carboxyanhydrides to form a protected copolymer-1

Methodology Applied
Scientific EffectPolymerization: Chemical Bonding

Data Source

PatentEP2046817B1Improved process for the preparation of copolymer-1
Publication Date: 2009.12.16 MOMENTA PHARMACEUTICALS INC
  • EP2046817B1 patent drawingFigure 1~1(c)
  • EP2046817B1 patent drawingFigure 2~2(c)
  • EP2046817B1 patent drawing

AI summary

The presently disclosed subject matter provides a novel method for preparing copolymer- 1. In one embodiment, a mixture of N-carboxyanhydrides (NCAs) comprising alanine, protected-glutamic acid, protected lysine, and tyrosine, and wherein glutamic acid includes a benzyl or methoxy protecting group and lysine includes a cyclic imide or Boc protecting group are treated with a polymerization initiator to initiate polymerization of the mixture of N-carboxyanhydrides and to thereby synthesize a protected copolymer- 1. The protected copolymer- 1 can then be treated with deprotecting groups and/or depolymerized to obtain a copolymer- 1 having a desired molecular weight.