Succinate Salt Form of a CDK4/6 Inhibitor for Oral Bioavailability

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Solution Overview

Problem

Existing compounds like N-Cyclopentyl-5-(2-((5-((4-ethylpiperazin-1-yl) methyl) pyridin-2-yl) amino)-5-fluoropyrimidin-4-yl)-4-methylthiazol-2-amine face issues with solubility, stability, and oral bioavailability, hindering their development as effective CDK inhibitors for treating proliferative disorders.

Innovation Solution

Conversion of the compound into pharmaceutically acceptable salts, particularly succinate, with specific preparation methods to enhance solubility and stability, and improve bioavailability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the compound is used in its original form, then it shows CDK inhibitory activity, but it has poor solubility and oral bioavailability

Engineering Contradiction:
ImproveCDK inhibitory activityVSAvoidsolubility and oral bioavailability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies parameter changes by converting the compound into different salt forms (succinate, maleate, fumarate, citrate, hydrochloride, sulfate, phosphate, nitrate, hydrobromide, methanesulfonate, benzenesulfonate, benzoate, p-toluenesulfonate, 1,2-ethanedisulfonate, 2-naphthalenesulfonate, hippurate, glutarate, adipate, ascorbate, malonate, gentisate, nicotinate, L-malate, L-tartrate, or DL-lactate). This chemical modification changes the physical and chemical parameters of the compound, particularly improving water solubility and oral bioavailability while maintaining CDK inhibitory activity.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the compound is converted to salt forms to improve solubility, then solubility and bioavailability improve, but the compound structure becomes more complex

Engineering Contradiction:
Improvesolubility and bioavailabilityVSAvoidcompound structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent uses salt formation as an intermediary approach. By introducing pharmaceutically acceptable counterions (such as succinate, maleate, fumarate, citrate, hydrochloride, sulfate, phosphate, nitrate, hydrobromide, methanesulfonate, benzenesulfonate, benzoate, p-toluenesulfonate, 1,2-ethanedisulfonate, 2-naphthalenesulfonate, hippurate, glutarate, adipate, ascorbate, malonate, gentisate, nicotinate, L-malate, L-tartrate, or DL-lactate), the compound's solubility and bioavailability are enhanced without fundamentally altering the core pharmacophore structure responsible for CDK inhibition.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4244222B1Succinate and crystal form thereof as therapeutics
Publication Date: 2025.11.26 AUCENTRA THERAPEUTICS PTY LTD
  • EP4244222B1 patent drawingFigure 1
  • EP4244222B1 patent drawingFigure 2
  • EP4244222B1 patent drawingFigure 3

AI summary

Disclosed are salts of N-Cyclopentyl-5-(2-((5-((4-ethylpiperazin-1-yl) methyl) pyridin-2-yl) amino)-5-fluoropyrimidin-4-yl)-4-methylthiazol-2-amine and polymorphs thereof, which are inhibitors of protein kinases, in particular cyclin-dependent kinase 4/6 (CDK4/6), and can be used to treat proliferative disorders, such as cancer, and other diseases related to protein kinase/CDK activity.