Allisartan Isoproxil Polymorph Crystallization Flowability

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Solution Overview

Problem

Allisartan isoproxil polymorphs in existing technologies exhibit electrostatic phenomena and poor flowability, leading to contamination and production inefficiencies, making it difficult to predict physicochemical properties and clinical efficacy.

Innovation Solution

A new allisartan isoproxil polymorph with non-electrostatic characteristics and improved flowability is developed, characterized by specific X-ray diffraction peaks and produced using a method involving a mixed solvent system, which includes dissolving allisartan isoproxil in a mixture of C3-C4 alcohols or their acetates and C5-C7 chain alkanes, followed by slow cooling and crystallization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If allisartan isoproxil polymorph is prepared using conventional methods, then the crystal structure is obtained, but electrostatic phenomenon and poor flowability occur

Engineering Contradiction:
Improvecrystal structure stabilityVSAvoidflowability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies parameter changes by modifying the solvent system composition (using specific ratios of alcohol and alkane), temperature profile (controlled cooling rates), and pH conditions to obtain a polymorph with improved flowability while maintaining structural stability. The specific parameters include solvent volume ratios, cooling rates, and crystallization temperatures that differentiate this polymorph from conventional preparations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If allisartan isoproxil polymorph is prepared using conventional methods, then the crystal structure is obtained, but electrostatic phenomenon and poor flowability occur

Engineering Contradiction:
Improvecrystal structure stabilityVSAvoidelectrostatic phenomenon
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent modifies physical-chemical parameters including solvent composition (alcohol-alkane mixtures with specific ratios), temperature conditions (controlled cooling from reflux to room temperature), and pH control to obtain a polymorph that exhibits reduced electrostatic phenomenon while maintaining crystal structure stability.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If different polymorphs of allisartan isoproxil are obtained, then various physicochemical properties are achieved, but prediction of clinical efficacy becomes difficult

Engineering Contradiction:
Improvephysicochemical properties variationVSAvoidpredictability of clinical efficacy
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent establishes specific parameter ranges for solvent composition (C3-C4 alcohol with C5-C7 alkane in defined ratios), temperature profiles (controlled cooling rates), and crystallization conditions that consistently yield a polymorph with predictable and reproducible physicochemical properties, thereby improving predictability of clinical efficacy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs feedback mechanisms through systematic characterization of the polymorph using XRD, DSC, and other analytical methods to confirm structure-property relationships. This feedback loop allows prediction of clinical efficacy based on confirmed polymorphic structure and measured physicochemical properties.

Inventive Principle:
Principle #23Feedback

4Ease of operation

If allisartan isoproxil crystal is ground to improve processing, then flowability may be enhanced, but dust generation and contamination increase

Engineering Contradiction:
ImproveflowabilityVSAvoiddust generation
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by optimizing the crystal morphology during the crystallization process itself, rather than relying on post-crystallization grinding. The controlled crystallization conditions produce crystals with inherent good flowability and reduced tendency to generate dust during subsequent handling and processing operations.

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

The new polymorph shows high stability, better flowability, and reduced electrostatic issues, enhancing production convenience and stability, leading to improved pharmaceutical compositions with enhanced clinical efficacy and safety for hypertension treatment.

Implementation Method 1

Dissolve allisartan isoproxil in the mixed solvent composed of solvent A and solvent B under heating

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

Crystal is precipitated by temperature reduction

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 3

Crystal is precipitated by temperature reduction

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 4

X-ray powder diffraction spectra (XRD spectra)

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Implementation Method 5

X-ray powder diffraction spectra (XRD spectra)

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP3159336B1Crystal of allisartan isoproxil, preparation method therefor and pharmaceutical composition containing same
Publication Date: 2019.08.07 SHENZHEN SALUBRIS PHARMA CO LTD
  • EP3159336B1 patent drawingFigure 1
  • EP3159336B1 patent drawingFigure 2
  • EP3159336B1 patent drawingFigure 3

AI summary

Disclosed are polymorph of allisartan isoproxil and a pharmaceutical composition thereof. The polymorph is non-electrostatic, highly flowable and highly stable, and can be used for treating hypertension and complications thereof.