Efavirenz Polymorph Crystallization via Seeding and Anti-Solvent
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for preparing polymorphic forms of efavirenz lack reproducibility, stability, and scalability, particularly under varying heat and humidity conditions, and do not consistently produce pure and stable forms.
Innovation Solution
A novel process involving dissolution of efavirenz in specific solvents, followed by cooling, seeding, and the addition of an anti-solvent to isolate pure polymorphic forms M1, I, II, β, and ω, utilizing techniques like freeze-drying and distillation to achieve high purity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing processes for preparing polymorphic forms of efavirenz are used, then various polymorphic forms can be obtained, but the processes lack reproducibility and stability under varying heat and humidity conditions
Solution Approach 1:
The patent applies parameter changes by systematically varying crystallization conditions including solvent types (formic acid, pyridine, acetic acid, ethyl acetate, toluene, hexane), temperatures (0-50°C ranges), and anti-solvent addition rates to obtain different polymorphic forms (M1, I, II, β, ω) with distinct XRD patterns and stability profiles under various heat and humidity conditions
Solution Approach 2:
The patent employs preliminary action through seeding techniques where pre-formed crystals of desired polymorphic forms are introduced to supersaturated solutions to guide and control the crystallization process, ensuring reproducible formation of specific polymorphic forms while reducing sensitivity to environmental variations
2Manufacturing precision
If existing purification methods are used, then crude efavirenz can be obtained, but the purity and stability are insufficient
Solution Approach 1:
The patent applies extraction principles by using anti-solvent addition (water, n-heptane, or isopropyl alcohol) to precipitate pure polymorphic forms from solution, effectively separating the desired product from impurities and achieving high purity levels (95-99% by HPLC) while maintaining stability
Solution Approach 2:
The patent utilizes phase transitions through controlled cooling of saturated solutions from 40-50°C to 0-25°C, inducing crystallization of polymorphic forms with specific physical properties, and through freeze-drying processes that transform liquid solvents into gas phase, leaving behind pure solid polymorphic forms with enhanced stability
3Manufacturing precision
If complex multiple purification steps are applied, then purity can be improved, but the process complexity and time increase
Solution Approach 1:
The patent merges multiple operations into integrated crystallization processes where dissolution, cooling, seeding, anti-solvent addition, and filtration are combined into sequential unit operations that achieve high purity (95-99% by HPLC) while reducing overall process complexity compared to traditional multi-step purifications
Solution Approach 2:
The patent employs intermediaries such as formic acid, pyridine, acetic acid, ethyl acetate, and toluene as solvents that facilitate the crystallization process, enabling efficient separation and purification of polymorphic forms through their specific solubility characteristics and ease of removal
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 process ensures consistent production of high-purity and stable polymorphic forms of efavirenz, maintaining physical and chemical stability across different temperature and humidity conditions.
Implementation Method 1
dissolving efavirenz in a solvent
Implementation Method 2
cooling the reaction mass followed by seeding the resultant
Implementation Method 3
cooling the reaction mass
Implementation Method 4
adding anti-solvent and isolating the pure efavirenz polymorphic Form β
Implementation Method 5
removing the solvent and isolating the efavirenz polymorphic Form β, wherein the solvent is removed by employing freeze drying or distillation method
Implementation Method 6
removing the solvent and isolating the efavirenz polymorphic Form β, wherein the solvent is removed by employing freeze drying or distillation method
Data Source
AI summary
Disclosed herein is a novel process for preparing polymorphic Forms of (S)-6-chloro-(cyclopropylethynyl)-1,4-di-hydro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one referred as M1, I, II, β, and ω.