Tigecycline Crystalline Forms via Controlled Evaporation
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Solution Overview
Problem
Current methods for preparing Tigecycline often result in amorphous forms with suboptimal solid state properties, such as flowability and dissolution rates, which can affect its therapeutic efficacy and stability, necessitating the use of additional excipients and complicating pharmaceutical formulations.
Innovation Solution
Development of crystalline forms of Tigecycline characterized by specific XRD patterns, achieved through crystallization from solvents like nitriles, dimethoxyethane, and n-heptane, which improve the drug's physical stability and flowability, and the use of processes that involve controlled evaporation and solvent selection to produce pure crystalline forms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Tigecycline is prepared by conventional methods, then the production process is simple, but the solid state properties are suboptimal with poor flowability and dissolution rates
Solution Approach 1:
The patent applies parameter changes by controlling crystallization conditions including solvent selection (water, alcohols, esters, ethers, nitriles), temperature ranges (0-50°C), pH adjustment (pH 2-8), and evaporation rates to obtain Tigecycline in desired crystalline forms with improved solid state properties while maintaining manufacturing feasibility
Solution Approach 2:
The patent utilizes phase transitions through controlled evaporation of solvents from Tigecycline solutions to induce crystallization. The process involves dissolving Tigecycline in selected solvents, maintaining specific temperatures, and allowing controlled evaporation to transform the drug from dissolved state to crystalline solid form with enhanced flowability and dissolution characteristics
2Speed
If amorphous Tigecycline is used, then the dissolution rate is faster, but the chemical and physical stability is reduced
Solution Approach 1:
The patent employs parameter changes by controlling crystallization parameters such as solvent type, temperature, pH, and evaporation rate to produce Tigecycline in controlled crystalline forms that achieve an optimal balance between dissolution rate and stability, avoiding both amorphous instability and excessive crystalline slow dissolution
3Device complexity
If poor flowability is present, then no additional excipients are needed, but the handling during processing is difficult
Solution Approach 1:
The patent applies parameter changes through controlled crystallization to produce Tigecycline with improved particle morphology, size distribution, and surface characteristics that inherently provide better flowability and handling properties during pharmaceutical processing, reducing the need for additional glidant excipients
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 forms exhibit enhanced chemical and physical stability, improved flowability, and controlled dissolution rates, allowing for more effective pharmaceutical formulations with targeted release profiles and improved handling characteristics.
Implementation Method 1
Tigecycline is crystallised from a solvent comprising a C1-5 nitrile
Implementation Method 2
U. S. Patent No. 5,675,030 describes a specific method for obtaining solid Tigecycline by evaporation from a dichloromethane solution
Data Source
AI summary
The present invention relates to the use of a solid crystalline form of Tigecycline in the manufacture of pharmaceutical compositions.