Crystalline Polymorph A of 15ß-Hydroxy-Osaterone Acetate

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Solution Overview

Problem

Conventional crystalline polymorphic form B of 15β-hydroxy-osaterone acetate has insufficient stability, poor powder flow properties, and rapid pharmacokinetic absorption leading to safety concerns due to varying active ingredient content and high maximum plasma concentration reached quickly.

Innovation Solution

The development of crystalline polymorphic form A, characterized by specific diffraction peaks and produced through crystallization in a mixed solvent of ethanol and water, offering improved stability, powder flow, and controlled pharmacokinetic profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If crystalline polymorphic form B is used, then the compound can be obtained through conventional synthesis methods, but the crystal has insufficient storage stability and decreases in purity with storage

Engineering Contradiction:
Improveease of manufactureVSAvoidstorage stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the crystallization conditions, specifically using a mixed solvent system of ethanol and water in a controlled temperature process to transform the crystal structure from form B to form A, thereby improving storage stability while maintaining manufacturability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions by controlling the crystallization process to induce formation of a new polymorphic form (form A) with superior stability characteristics, achieving a transition from the less stable form B to the more stable form A through controlled solvent removal and temperature management

Inventive Principle:
Principle #36Phase transitions

2Ease of manufacture

If crystalline polymorphic form B is used, then the compound can be produced through existing processes, but the crystal fails to maintain the crystal form by pressure action such as pulverization or crushing and decreases in purity

Engineering Contradiction:
Improveease of manufactureVSAvoidcrystal form stability under pressure
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent modifies physical parameters of the crystal lattice by changing the crystallization solvent system and temperature profile, resulting in form A which possesses enhanced mechanical strength and resistance to pressure-induced degradation during pulverization and crushing operations

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If crystalline polymorphic form B is used, then the compound can be obtained through conventional methods, but the crystal has low powder flow property and varying active ingredient content in preparation

Engineering Contradiction:
Improveease of manufactureVSAvoidpowder flow property
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent changes the physical parameters of the crystal through controlled crystallization in ethanol-water mixed solvent, producing form A with modified surface characteristics and particle morphology that significantly improve powder flow properties and enable uniform active ingredient distribution in pharmaceutical preparations

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If crystalline polymorphic form B is used, then the compound can be synthesized through established processes, but the crystal has high C max and short T max leading to rapid absorbability and safety concerns

Engineering Contradiction:
Improveease of manufactureVSAvoidsafety concern due to rapid absorbability
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the bioavailability parameters by changing the crystal structure from form B to form A through controlled crystallization, resulting in altered dissolution characteristics that reduce C max and extend T max, thereby decreasing rapid absorbability and associated safety concerns

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

Crystalline polymorphic form A exhibits enhanced stability, workability, and safety with reduced rapid absorbability, maintaining active ingredient consistency and prolonged maximum plasma concentration, suitable for stable pharmaceutical preparations.

Implementation Method 1

heating and dissolving 15β-hydroxy-osaterone acetate in a mixed solvent of ethanol and water, and cooling (particularly, gradually cooling) the resulting solution

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP3456729B1Crystalline polymorph of 15ß-hydroxy-osaterone acetate
Publication Date: 2020.09.02 ASKA PHARMACEUTICAL CO LTD
  • EP3456729B1 patent drawingFigure 1~2
  • EP3456729B1 patent drawingFigure 3~4
  • EP3456729B1 patent drawingFigure 5

AI summary

Provided is a crystalline polymorphic form A of 15β-hydroxy-osaterone acetate having an improved stability (storage stability, pulverization stability, and absorption characteristics). In a powder X-ray diffraction spectrum, characteristic diffraction peaks of the crystalline polymorphic form A of 15β-hydroxy-osaterone acetate appear at diffraction angles 2θ of 9.6° ± 0.2°, 17.1° ± 0.2°, and 20.2° ± 0.2°. The crystalline polymorphic form A has a melting point of 280 to 283°C and is a prism crystal.