Sofosbuvir Form E Crystallization for Polymorphic Purity and Flowability
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Solution Overview
Problem
Current processes for producing crystalline forms of Sofosbuvir are impractical for large-scale preparation and result in polymorphically impure materials, with Form 6 exhibiting electrostatic charges leading to poor flowability and content uniformity issues in pharmaceutical compositions.
Innovation Solution
Development of a new crystalline form, Form E of Sofosbuvir, characterized by specific X-ray diffraction patterns and processes involving solvent systems, seeding, and anti-solvent addition to produce a polymorphically pure, stable, and easily handleable form with improved hygroscopic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If crystalline forms of Sofosbuvir are prepared by conventional crystallisation methods, then crystalline material is obtained, but the material is polymorphically impure and exhibits poor flowability due to electrostatic charges
Solution Approach 1:
The patent applies parameter changes by modifying crystallisation conditions including temperature (0-25°C), solvent composition (aqueous ethanol with 50-95% ethanol), and pH (adjusted to 3-5 using HCl). These parameter adjustments enable selective formation of Form E crystals with desired polymorphic purity and reduced electrostatic charging, improving both manufacturing precision and ease of operation.
Solution Approach 2:
The patent utilizes phase transitions during the crystallisation process, where Sofosbuvir transitions from dissolved state in aqueous ethanol to crystalline Form E upon cooling and anti-solvent addition. This controlled phase transition ensures polymorphically pure material formation while minimizing electrostatic charge accumulation that would otherwise impair flowability.
2Reliability
If Form 6 of Sofosbuvir is used in pharmaceutical compositions, then the active ingredient is available, but content uniformity is poor due to electrostatic charging and poor flowability
Solution Approach 1:
The patent changes physical parameters of Sofosbuvir by developing Form E with different crystalline structure characteristics compared to Form 6. This polymorphic transformation alters surface properties and electrostatic charge tendencies, resulting in improved flowability and content uniformity while maintaining pharmaceutical reliability.
3Productivity
If conventional crystallisation processes are used for large-scale preparation, then production capacity is achieved, but polymorphic impurity and handling difficulties persist
Solution Approach 1:
The patent implements parameter changes in the crystallisation process including temperature control (0-25°C), solvent system composition (aqueous ethanol), and pH adjustment (3-5). These modified parameters enable scalable production while consistently yielding polymorphically pure Form E material that is free from the handling difficulties associated with conventional methods.
Solution Approach 2:
The patent uses aqueous ethanol as an intermediary solvent system and HCl as a pH-adjusting mediator to control the crystallisation process. These intermediaries facilitate the formation of pure Form E crystals at scale by mediating the interaction between Sofosbuvir molecules and the crystallisation environment, ensuring both productivity and manufacturing precision.
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
Form E of Sofosbuvir is stable, exhibits improved flowability and compressibility, and maintains low hygroscopicity, facilitating easier handling and storage, and is suitable for high-drug-load formulations, enhancing the preparation of pharmaceutical compositions.
Implementation Method 1
The Form E is prepared by dissolving Sofosbuvir in a solvent and adding an antisolvent and allowing the mixture to stand in a sealed vessel for 15-24 hours under certain conditions
Implementation Method 2
Form E of Sofosbuvir is characterised by an X-ray diffraction pattern having peaks at 8.1, 12.1, 12.4, 13.5, 16.2 and 17.2 degrees two theta ± 0.1 degrees two theta
Data Source
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AI summary
The present disclosure encompasses solid state forms of Sofosbuvir, processes for their production, and pharmaceutical compositions thereof.