Chiral Crystallization Purification of Fluorobiphenyl Propionic Acid

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Solution Overview

Problem

Pharmaceutical products containing (R)-(−)-2-(2-fluoro-4-biphenylyl) propionic acid, used for long-term administration, face challenges due to high impurity levels, particularly product-related and process-related impurities, residual solvents, and heavy metals, which can pose health risks and require stringent regulatory limits.

Innovation Solution

Development of drug substance preparations, pharmaceutical compositions, and dosage forms with limited amounts of specific impurities, including product-related and process-related impurities, residual solvents, and heavy metals, using chiral crystallization to purify (R)-(−)-2-(2-fluoro-4-biphenylyl) propionic acid, ensuring compliance with regulatory limits and minimizing patient exposure to impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If conventional drug substance preparations are used for long-term administration, then therapeutic effect is achieved, but patient exposure to impurities is amplified

Engineering Contradiction:

Improveduration of administrationVSAvoidpatient exposure to impurities

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by implementing multiple purification steps (chiral resolution, crystallization, filtration) before the drug substance is formulated into final dosage forms. This advance purification ensures that impurity levels are controlled from the outset, preventing accumulation of harmful substances during long-term administration.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the challenge of chiral impurities into a benefit by employing chiral resolution techniques that not only remove harmful enantiomers but also establish a purified, therapeutically active configuration. The chiral purification process transforms what would be harmful impurities into a controlled, beneficial therapeutic agent with predictable pharmacokinetics.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

If chiral resolution is performed to reduce enantiomeric impurities, then product-related impurity levels decrease, but additional processing steps are required

Engineering Contradiction:

Improveenantiomeric purityVSAvoidnumber of processing steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by systematically adjusting crystallization conditions (temperature, solvent composition, pH, concentration) to optimize chiral resolution efficiency. By modifying these physical-chemical parameters, the process achieves high enantiomeric purity through controlled crystallization rather than requiring multiple sequential purification steps.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions, specifically controlled crystallization from solution, to separate enantiomers. The chiral resolution process exploits differential solubility and crystal formation of diastereomeric salts, allowing the desired enantiomer to be recovered in high purity through filtration and washing, thereby simplifying the overall purification sequence.

Inventive Principle:

Principle #36Phase transitions

3Manufacturing precision

If multiple purification steps are implemented to reduce all impurity types, then impurity levels decrease, but production complexity and cost increase

Engineering Contradiction:

Improveoverall impurity levelVSAvoidproduction complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent merges multiple purification objectives into an integrated process sequence where chiral resolution, crystallization, and filtration steps work synergistically. By combining these operations in a coordinated manner rather than as separate, isolated steps, the process achieves comprehensive impurity removal while maintaining manufacturing efficiency and reducing overall process complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs intermediary substances (chiral resolving agents, solvents, buffers) that facilitate purification without becoming permanent contaminants. These intermediaries enable selective separation of impurities during controlled reactions and crystallizations, then are easily removed in subsequent washing and filtration steps, achieving high purity without requiring complex, multi-stage purification equipment.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution allows for the production of pharmaceutical compositions and dosage forms with therapeutically desirable pharmacokinetic profiles and physical characteristics, suitable for long-term administration, while maintaining impurity levels within safe and regulatory-compliant limits, particularly for conditions like Alzheimer's disease.

Implementation Method 1

Methodology Applied

Scientific EffectChiral crystallization: Crystallisation

Data Source

PatentUS8653139B2Drug substance preparations, pharmaceutical compositions and dosage forms

Publication Date: 2014.02.18 AESICA PHARMA

AI summary

The invention relates to drug substance preparations, pharmaceutical compositions and dosage forms containing (R)-(−)-2-(2-fluoro-4-biphenylyl) propionic acid as the active pharmaceutical ingredient, and limited amounts of specific product-related and process-related impurities.