Anhydrous Polymorph A2 of Compound A for Ocular Formulation Stability

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Solution Overview

Problem

Existing pharmaceutical formulations of Compound A, a selective adenosine A1 receptor agonist, face challenges with variability in particle growth size and stability, which affects its physical and chemical properties, solubility, and formulation handling characteristics, necessitating the discovery of stable polymorphic forms for effective intraocular pressure treatment.

Innovation Solution

The development of anhydrous polymorph A2 of Compound A, characterized by specific crystal data and methods of preparation, including heating in a liquid vehicle to achieve at least 75% purity, micronization, and formulation with surfactants and preservatives for enhanced stability and ophthalmic administration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing pharmaceutical formulations of Compound A are used, then the drug can be administered for treating elevated intra-ocular pressure, but the formulations exhibit variability in particle growth size and stability, affecting physical and chemical properties

Engineering Contradiction:
ImprovestabilityVSAvoidparticle growth size variability
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by identifying and characterizing different polymorphic forms of Compound A, each with distinct crystal structures and physical properties. By selecting specific polymorphic forms (anhydrous forms A1 and A2) with defined crystal parameters, the invention achieves consistent particle characteristics and improved stability, resolving the variability issue in existing formulations

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transitions between different polymorphic forms of Compound A. The patent describes methods to control and achieve specific polymorphic forms through controlled crystallization and phase transition processes, ensuring consistent particle growth and enhanced stability in the final pharmaceutical formulation

Inventive Principle:
Principle #36Phase transitions

2Adaptability or versatility

If different polymorphic forms of Compound A are used, then formulation properties can be controlled, but the physical and solid state chemical properties vary between polymorphs

Engineering Contradiction:
Improveformulation properties controlVSAvoidphysical and solid state chemical properties
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by characterizing specific regions or aspects of each polymorphic form's properties. The invention identifies distinct crystal structures, melting points, and solubility characteristics for each polymorphic form (A1 and A2), allowing selective use of specific property profiles depending on formulation requirements while maintaining compositional stability within each form

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If Compound A is prepared using existing procedures, then the compound can be synthesized, but the product may contain mixtures of polymorphic forms requiring additional purification

Engineering Contradiction:
Improvesynthesis procedureVSAvoidpolymorphic form purity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by incorporating specific crystallization conditions and polymorph selection steps directly into the synthesis procedure. The invention describes methods to obtain the desired polymorphic form (A1 or A2) as the primary or sole product during the crystallization step, eliminating the need for subsequent polymorph purification and simplifying the overall manufacturing process

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 anhydrous polymorph A2 form provides improved stability, solubility, and handling characteristics, ensuring consistent drug delivery and prolonged stability in ocular formulations, effectively reducing intraocular pressure.

Implementation Method 1

heating in a liquid vehicle to achieve at least 75% purity

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

The development of anhydrous polymorph A2 of Compound A, characterized by specific crystal data

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP2807178B9Anhydrous polymorphs of (2r,3s,4r,5r)-5-(6-(cyclopentylamino)-9h-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl) } methyl nitrate and processes of preparation thereof
Publication Date: 2017.11.29 INOTECK PHARMA CORP
  • EP2807178B9 patent drawingFigure 1
  • EP2807178B9 patent drawingFigure 2
  • EP2807178B9 patent drawingFigure 3

AI summary

The present invention provides novel anhydrous polymorph forms of 2R,3S,4R,5R)-5-(6-(cyclopentylamino)-9H-purin-9-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methyl nitrate (Compound A). The present invention also provides processes for preparation of the anhydrous polymorphic forms of compound A.