PDE9 Inhibitor Monohydrate Crystal Form for Solubility and Stability
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Solution Overview
Problem
Existing forms of the PDE9 inhibitor 6-[(3S,4S)-4-methyl-1-(pyrimidin-2-ylmethyl)pyrrolidin-3-yl]-3-tetrahydropyran-4-yl-7H-imidazo[1,5-a]pyrazin-8-one lack enhanced solubility, oral bioavailability, and physical stability, which are crucial for effective drug development and treatment of diseases like sickle cell disease.
Innovation Solution
The development of a monohydrate crystalline form (MH2) of the PDE9 inhibitor, characterized by specific XRPD peaks and thermal properties, which is prepared through controlled crystallization processes using specific solvents, enhancing its solubility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amorphous or hydrate forms of the compound are used, then the compound can be obtained, but the compound exhibits poor flow properties, variable water content, and inconsistent density
Solution Approach 1:
The patent applies parameter changes by transforming the compound from amorphous or hydrate forms to a defined crystalline form (Form A). This phase transition changes the physical parameters including water content (from variable to <5%), density (from inconsistent to 1.37-1.40 g/cm³), and flow properties (from poor to good). The crystalline structure provides consistent, reproducible physical properties that resolve the reliability issue.
Solution Approach 2:
The patent utilizes phase transitions by converting the compound from amorphous or hydrate phases to a crystalline phase. This phase change eliminates the variable water content characteristic of hydrates and the poor flow properties of amorphous materials. The crystalline form exhibits consistent density and improved flow characteristics, directly addressing the technical problems stated in the background.
2Adaptability or versatility
If multiple crystalline forms (polymorphs) exist for the compound, then the compound can be obtained in different forms, but it becomes difficult to determine which form is present and to control conversion between forms
Solution Approach 1:
The patent applies the taking out principle by isolating and characterizing a specific crystalline form (Form A) from the mixture of possible polymorphs. Instead of dealing with all possible crystalline forms, the invention extracts and defines the properties of Form A specifically, providing clear identification criteria (PXRD patterns, density range, water content limits) that simplify form determination and control.
Solution Approach 2:
The patent uses parameter changes to distinguish and control crystalline forms by establishing specific parameter ranges for Form A: density (1.37-1.40 g/cm³), water content (<5%), and characteristic PXRD patterns. These defined parameters provide clear criteria for identifying and controlling the crystalline form, reducing the complexity of polymorph management.
3Productivity
If the compound is obtained without proper crystalline form control, then production can proceed, but the final product exhibits poor flow properties and inconsistent density affecting tablet compression
Solution Approach 1:
The patent applies preliminary action by ensuring the compound is converted to the desired crystalline form (Form A) before the tablet compression step. The method establishes specific crystallization conditions and provides identification criteria that confirm the correct form is present prior to manufacturing. This preliminary form control prevents downstream processing issues during tablet compression, maintaining both productivity and manufacturing precision.
Solution Approach 2:
The patent uses parameter changes to control the crystalline form parameters (density, water content, crystal structure) before the compound enters the manufacturing process. By establishing the correct crystalline form with specific parameters (density 1.37-1.40 g/cm³, water content <5%) before production, the patent ensures good flow properties and consistent tablet compression without sacrificing productivity.
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 monohydrate form MH2 exhibits improved solubility and stability, enabling more effective pharmaceutical compositions for treating sickle cell disease by inhibiting PDE9 activity and increasing fetal hemoglobin production.
Implementation Method 1
crystalline polymorph forms of 6-[(3S,4S)-4-methyl-1-(pyrimidin-2-ylmethyl)pyrrolidin-3-yl]-3-tetrahydropyran-4-yl-7H-imidazo[1,5-a]pyrazin-8-one
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
The present disclosure relates to crystalline polymorph forms of 6-[(3S,4S)-4-methyl-1-(pyrimidin-2-ylmethyl)pyrrolidin-3-yl]-3-tetrahydropyran-4-yl-7H-imidazo[1,5-a]pyrazin-8-one.