Pyrazolopyrimidine Ester Form II for Stable BTK Prodrug Storage
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Solution Overview
Problem
The amorphous form of the pyrazolopyrimidine ester compound used as a BTK inhibitor prodrug exhibits poor stability and is susceptible to degradation under normal storage conditions, posing challenges for its use in pharmaceutical applications.
Innovation Solution
Development of a crystalline form (Form II) characterized by specific XRPD peaks and improved stability, prepared through crystallization methods using a mixed solvent system, which includes a good solvent and a poor solvent, and optionally with crystal seeds, ensuring high purity of the amorphous compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compound is synthesized using the method disclosed in CN 202111131059.0, then the compound can be obtained, but it exists in amorphous form with poor stability and is susceptible to heat and moisture
Solution Approach 1:
The patent applies parameter changes by modifying the physical state of the compound from amorphous to crystalline form. Specifically, it identifies and characterizes three crystalline forms (Form I, Form II, and Form III) with distinct XRPD patterns, where Form II demonstrates superior stability. This phase transition from amorphous to crystalline state fundamentally changes the stability parameters, resolving the contradiction between obtainability and stability.
Solution Approach 2:
The patent develops a composite solvent system consisting of a good solvent (where the compound is soluble) and a poor solvent (where the compound has limited solubility). This composite solvent approach enables controlled crystallization that produces stable crystalline forms. The synergistic interaction between the two solvents creates optimal conditions for forming stable crystal structures, thereby resolving the stability issue.
2Ease of manufacture
If the amorphous compound is stored under regular storage conditions, then storage is simple, but significant degradation occurs after 10 days at 40°C and almost complete degradation at 60°C and 75% RH
Solution Approach 1:
The patent resolves this contradiction by changing the physical state parameter from amorphous to crystalline. The crystalline forms, particularly Form II, exhibit enhanced stability that allows storage under regular conditions without significant degradation. This parameter change maintains both storage simplicity and reliability simultaneously.
Solution Approach 2:
The patent applies beforehand cushioning by developing a crystallization process that preemptively creates stable crystalline forms before storage. This prior treatment prevents degradation issues that would otherwise occur during storage, cushioning against the harmful effects of heat and moisture exposure.
3Reliability
If crystalline form is developed to improve stability, then stability is enhanced, but additional processing steps are required
Solution Approach 1:
The patent uses parameter changes (phase transition from amorphous to crystalline) to achieve the desired stability improvement. While this does add processing steps, the method is systematically described with clear parameters for identifying the crystalline forms, making the additional complexity manageable and justified by the significant stability gains.
Solution Approach 2:
The patent employs solvent systems as intermediaries to facilitate the transformation from amorphous to crystalline form. The good solvent dissolves the compound, and the poor solvent induces crystallization, acting as a mediator in the phase transition process. This intermediary approach provides a controlled and reproducible method for obtaining stable crystalline forms.
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 form II demonstrates enhanced stability, allowing long-term storage without special environmental controls and maintaining high purity, making it suitable for pharmaceutical use.
Implementation Method 1
Development of a crystalline form (Form II) characterized by specific XRPD peaks and improved stability, prepared through crystallization methods using a mixed solvent system
Data Source
AI summary
The present invention provides a crystalline form Form II of a pyrazolopyrimidine ester compound of the structure of formula (I)This crystalline form has been characterized using X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and infrared (IR) spectroscopy. The present invention also provides a method of preparing the crystalline form Form II of the pyrazolopyrimidine ester compound. This crystalline form allows long-term storage without special requirements in respect of temperature, light, humidity or oxygen level and is significantly advantageous in terms of stability. Moreover, the method involves simple steps and provides good reproducibility and excellent purity. It has a promising prospect of extensive application.