Polymorph I Mono-Phosphate Salt mGlu5 Modulator
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Solution Overview
Problem
The existing form of 6-fluoro-2-[4-(pyridin-2-yl)but-3-yn-1-yl]imidazo[1,2-a]pyridine has limited aqueous solubility, which hampers its pharmacological properties, whereas its mono-phosphate salt exhibits significantly improved solubility, making it a more effective compound for treating central nervous system disorders and other conditions modulated by mGlu5 receptors.
Innovation Solution
The development of a crystalline form (Polymorph I) of the 6-fluoro-2-[4-(pyridin-2-yl)but-3-yn-1-yl]imidazo[1,2-a]pyridine mono-phosphate salt, characterized by specific X-Ray diffraction peaks and infrared spectra, which is produced through salt formation with phosphoric acid and subsequent precipitation, offering enhanced solubility and pharmaceutical suitability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the free base form of 6-fluoro-2-[4-(pyridin-2-yl)but-3-yn-1-yl]imidazo[1,2-a]pyridine is used, then the compound maintains its original chemical structure and stability, but the aqueous solubility is limited (0.5 mg/mL)
Solution Approach 1:
The patent applies parameter changes by converting the free base form to a mono-phosphate salt form, which fundamentally alters the chemical parameters of the compound. This salt formation increases aqueous solubility from 0.5 mg/mL to 21.0-32.5 mg/mL (40-65 fold improvement) while maintaining the core pharmacological activity against mGlu5 receptors. The parameter change from base to salt form resolves the solubility limitation without requiring complex formulation techniques.
2Quantity of substance
If the mono-phosphate salt form is used, then the aqueous solubility increases significantly (21.0 to 32.5 mg/mL), but the compound requires salt formation process and crystalline form control
Solution Approach 1:
The patent addresses crystalline form control by identifying and characterizing specific polymorphic forms of the mono-phosphate salt. The invention describes Polymorph I with distinct X-ray diffraction peaks at 2θ = 8.4, 10.2, 12.5, 15.7, 16.8, 18.6, 20.5, 21.3, 28.1, and 29.4 degrees. By controlling the phase transition to this specific polymorphic form during crystallization, the patent ensures reproducible solubility and stability while managing the complexity of salt formation through standardized crystallization protocols.
3Quantity of substance
If salt formation with phosphoric acid is performed, then the solubility is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent uses phosphoric acid as an intermediary substance to facilitate salt formation with the free base. This intermediary approach allows controlled conversion to the mono-phosphate salt form, achieving the desired solubility enhancement (40-65 fold increase) through a well-defined chemical reaction. The intermediary phosphoric acid enables systematic control of the salt formation process, including pH management and crystallization conditions, thereby resolving the manufacturing complexity through standardized chemical protocols.
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 of the mono-phosphate salt significantly improves the solubility of the compound, allowing for better pharmacological properties and effective use in treating various disorders related to mGlu5 receptors, including central nervous system disorders, pain, and psychiatric conditions.
Implementation Method 1
The mono-phosphate of 6-fluoro-2-[4-(pyridin-2-yl)but-3-yn-1-yl]imidazo[1,2-a]pyridine exhibits surprisingly much better solubility characteristics as compared to the corresponding free base
Implementation Method 2
characterized by at least 3 peaks selected from X-Ray diffraction peaks obtained with a Cu Kα radiation at 2 θ (2 Theta (deg)) = 8.4, 10.2, 12.5, 15.7, 16.8, 18.6, 20.5, 21.3, 28.1, 29.4
Implementation Method 3
characterized by at least 3 peaks selected from X-Ray diffraction peaks obtained with a Cu Kα radiation
Implementation Method 4
characterized by an infrared spectrum having sharp bands at 3059, 2937, 2233, 1592, 1564, 1537, 1515, 1477, 1429, 1317, 1262, 1168, 1162, 1117, 863, 819, 772, 691
Data Source
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AI summary
The present invention relates to crystalline and amorphous forms of 6-fluoro-2-[4-(pyridin-2-yl)but-3-yn-1-yl]imidazo[1,2-a]pyridine mono-phosphate salt and methods of making these solid forms thereof. The invention compounds are modulators of mGlu5 which are useful for the treatment or prevention of central nervous system disorders as well as other disorders modulated by mGlu5 receptors. The invention is also directed to pharmaceutical compositions and the use of such compounds in the manufacture of medicaments, as well as to the use of such compounds for the prevention and treatment of such diseases in which mGlu5 is involved.