Trans-Clomiphene Monocitrate Crystallization for Purity and Solubility

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Solution Overview

Problem

Current methods for preparing Clomiphene and trans-Clomiphene citrate suffer from contamination by unknown impurities, poor solubility in water, and stability issues, leading to difficulties in industrial manufacturing and pharmaceutical applications.

Innovation Solution

A stable solid form of trans-Clomiphene monocitrate is developed through treatment with citric acid monohydrate in an organic solvent, resulting in a crystalline form with improved thermal stability, solubility, and crystal habit, including needle-shaped crystals, which enhance manufacturing and pharmaceutical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods are used to prepare Clomiphene and trans-Clomiphene citrate, then the preparation process is simple, but the product contains unknown impurities and has poor chemical purity

Engineering Contradiction:
Improvechemical purityVSAvoidpreparation process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The preparation process is divided into multiple sequential steps: (a) resolving geometric isomers using chiral resolving agent, (b) isolating trans-Clomiphene, (c) converting to citrate salt, and (d) recrystallization. This segmentation allows each step to address specific purification needs, achieving high chemical purity (>99%) by systematically removing impurities at each stage rather than relying on a single simple step.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If conventional solid forms of trans-Clomiphene citrate are used, then the manufacturing process is straightforward, but the solubility in water is poor

Engineering Contradiction:
Improvemanufacturing easeVSAvoidsolubility
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent identifies and characterizes different polymorphic forms of trans-Clomiphene citrate with distinct crystal structures. By selecting and controlling the formation of specific polymorphic forms through adjusted crystallization parameters (solvent type, temperature, pH), the patent achieves enhanced water solubility while maintaining manufacturing feasibility. The specific polymorphic form described provides optimal balance between solubility and ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If conventional solid forms of trans-Clomiphene citrate are used, then the preparation is simple, but the thermal stability and storage stability are insufficient

Engineering Contradiction:
Improvepreparation complexityVSAvoidstability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs preliminary recrystallization steps before final product formation to ensure complete removal of impurities and establishment of the desired polymorphic form. This preliminary action of controlled crystallization from specific solvent systems pre-establishes the stable solid form, ensuring enhanced thermal stability and storage stability throughout the product lifecycle without requiring complex stabilization additives or processes.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If conventional crystallization methods are used, then the crystal habit is non-optimized, but the filtration speed is slow

Engineering Contradiction:
Improvefiltration speedVSAvoidcrystal habit
Core Design Contradiction:
ProductivityVSShape

Solution Approach 1:

The patent controls crystallization parameters including solvent selection, temperature profiles, and pH conditions to induce formation of specific crystal habits with optimized morphology. These parameter adjustments promote growth of crystal forms with surface characteristics and shapes that facilitate rapid filtration and easier separation from mother liquor, directly improving productivity without requiring complex downstream processing equipment.

Inventive Principle:
Principle #35Parameter changes

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 new solid form of trans-Clomiphene monocitrate exhibits higher chemical purity, improved solubility, and enhanced stability, facilitating faster filtration and better bioavailability, making it suitable for industrial manufacturing and pharmaceutical applications.

Implementation Method 1

A stable solid form of trans-Clomiphene monocitrate is developed through treatment with citric acid monohydrate in an organic solvent, resulting in a crystalline form with improved thermal stability, solubility, and crystal habit

Methodology Applied
Scientific EffectCrystallisation: Crystallisation

Implementation Method 2

resulting in a crystalline form with improved thermal stability, solubility, and crystal habit, including needle-shaped crystals

Methodology Applied
Scientific EffectCrystallisation: Crystallisation

Data Source

PatentEP3083552B1Stable solid forms of enclomiphene and enclomiphene citrate
Publication Date: 2018.03.14 F I S FAB ILTALIANA SINTETICI SPA
  • EP3083552B1 patent drawingFigure 1
  • EP3083552B1 patent drawingFigure 2
  • EP3083552B1 patent drawingFigure 3

AI summary

The present invention refers to new solid forms of Enclomiphene citrate and Enclomiphene base, processes for preparing thereof and uses.