Pyrrolopyridine Crystal Forms Balancing Stability and Solubility

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Solution Overview

Problem

Existing pyrrolopyridine derivatives face issues with low solubility and bioavailability due to crystalline forms, and amorphous forms are unstable, leading to difficulties in drug release and blood concentration control.

Innovation Solution

Development of crystalline forms A, B, C, and D of pyrrolopyridine derivatives, characterized by specific X-ray diffraction patterns and DSC endothermic transition peaks, produced through solvent-based methods, including stirring and drying processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If crystalline form is used for pyrrolopyridine derivative, then stability is improved, but solubility and bioavailability deteriorate

Engineering Contradiction:
ImprovestabilityVSAvoidsolubility
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by discovering and characterizing multiple crystalline forms (Form A, B, C, D) with different physical properties through controlled crystallization processes. Each form exhibits distinct melting points, X-ray diffraction patterns, and solubility characteristics, allowing optimization of both stability and bioavailability by selecting appropriate crystalline forms for specific pharmaceutical applications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions through differential scanning calorimetry (DSC) to identify and characterize crystalline forms by detecting endothermic transition peaks. The phase change from amorphous to crystalline state is harnessed to achieve stable pharmaceutical formulations while maintaining acceptable solubility profiles through careful control of crystallization conditions

Inventive Principle:
Principle #36Phase transitions

2Quantity of substance

If amorphous form is used for pyrrolopyridine derivative, then solubility is improved, but stability deteriorates

Engineering Contradiction:
ImprovesolubilityVSAvoidstability
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent employs parameter changes by systematically varying crystallization conditions (solvent type, temperature, pH) to transform amorphous forms into stable crystalline forms. This transformation maintains solubility while significantly improving stability, as demonstrated by the consistent performance of crystalline forms A-D in pharmaceutical formulations

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If crystalline form is used for pyrrolopyridine derivative, then stability is improved, but bioavailability deteriorates

Engineering Contradiction:
ImprovestabilityVSAvoidbioavailability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent leverages phase transitions and polymorphic forms to optimize bioavailability while maintaining stability. By identifying crystalline forms with specific melting points and solubility characteristics, the patent achieves formulations that maintain drug stability during storage while ensuring adequate bioavailability through controlled release and dissolution properties

Inventive Principle:
Principle #36Phase transitions

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 crystalline forms exhibit low hygroscopicity, stability, and improved solubility, ensuring stable pharmaceutical formulations and high bioavailability.

Implementation Method 1

which has a powder X-ray diffraction pattern comprising peaks at diffraction angles (2Θ±0.2°) of 9.26°, 10.47°, 12.76°, 14.70°, 15.83°, and 16.61°

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Implementation Method 2

the crystalline form A may have a differential scanning calorimetry (DSC) endothermic transition peak at 208 to 215 °C when the heating rate is 10 °C/min

Methodology Applied
Scientific EffectDifferential scanning calorimetry: Calorimetry

Data Source

PatentEP4671241A1Crystalline form of pyrrolopyridine derivative
Publication Date: 2025.12.31 ST PHARM CO LTD
  • EP4671241A1 patent drawingFigure 1~2
  • EP4671241A1 patent drawingFigure 3~4
  • EP4671241A1 patent drawingFigure 5~6

AI summary

The present invention pertains to: a polymorph of a pyrrolopyridine derivative which is a non-catalytic site integrase inhibitor; and a method for producing same. The novel polymorph of the present invention exhibits excellent non-hygroscopicity and stability and is thus suitable for pharmaceutical preparations.