Besylate Benzodiazepine Polymorphs for Moisture-Stable Formulation
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Solution Overview
Problem
The free base of the compound Methyl 3-[(4S)-8-bromo-1-methyl-6-(2-pyridinyl)-4H-imidazol[1,2-a][1,4]benzodiazepin-4-yl]propanoate exhibits instability at elevated temperatures and high humidity, leading to deliquescence and significant content loss.
Innovation Solution
The formation of highly crystalline benzene sulfonic acid besylate salts with specific polymorphic forms, such as besylate Forms 1 to 4, which exhibit improved thermal stability and low hygroscopicity, is achieved through reaction with benzene sulfonic acid in various solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the free base of the compound is stored at elevated temperatures and high humidity, then the compound remains in its original form, but the compound exhibits deliquescence and content loss
Solution Approach 1:
The patent changes the physical and chemical parameters of the compound by forming a besylate salt, which fundamentally alters its hygroscopic properties. The salt form exhibits different moisture absorption characteristics compared to the free base, transforming it from a hygroscopic substance to a low-hygroscopicity material that maintains stability under humid conditions.
Solution Approach 2:
The invention creates a composite structure by combining the compound with benzene sulfonic acid to form a salt. This composite material (the besylate salt) exhibits improved stability and low hygroscopicity, effectively resolving the contradiction between reliability and hygroscopicity by creating a new material with superior properties.
2Reliability
If the free base of the compound is stored at elevated temperatures, then the compound remains stable, but the compound shows notable decreases in content
Solution Approach 1:
The patent changes the thermal stability parameter of the compound by forming a besylate salt. The salt form exhibits improved thermal stability that prevents degradation and content loss at elevated temperatures, while maintaining the desired pharmaceutical properties. This parameter change transforms the compound from temperature-sensitive to thermally stable.
3Reliability
If crystalline polymorphic forms of the besylate salt are produced, then the salt shows improved thermal stability and low hygroscopicity, but the manufacturing process becomes more complex
Solution Approach 1:
The patent controls the crystallization process by adjusting parameters such as solvent selection, temperature profiles, and cooling rates to obtain specific polymorphic forms. By optimizing these parameters, the process achieves the desired thermal stability and low hygroscopicity while maintaining manufacturing feasibility through controlled crystallization techniques.
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 besylate salts demonstrate enhanced stability and solubility, maintaining structural integrity and chemical purity under humid conditions, suitable for pharmaceutical applications.
Implementation Method 1
the formation of highly crystalline benzene sulfonic acid besylate salts with specific polymorphic forms, such as besylate Forms 1 to 4
Implementation Method 2
show good thermal stability, low hygroscopicity and high aqueous solubility
Data Source
AI summary
The invention relates to besylate salts of the compound of formula (I):Methods of preparing the salts, and their use as medicaments, in particular for sedative or hypnotic, anxiolytic, muscle relaxant, or anticonvulsant purposes is also described.