Tigecycline Dihydrochloride Crystalline Form C Solubility Stability
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Solution Overview
Problem
There is a need for a crystalline form of Tigecycline dihydrochloride with high water solubility and suitable stability properties for the formulation of an anti-infective medicament, as existing forms lack sufficient solubility and stability for effective use in pharmaceutical compositions.
Innovation Solution
The development of crystalline form C of Tigecycline dihydrochloride, characterized by specific X-ray powder diffraction and infrared spectrum patterns, is achieved through a process involving slurry formation in acetonitrile or a mixture with methylene chloride, addition of hydrochloric acid, and stirring within a defined temperature range, resulting in a form with enhanced solubility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing crystalline forms of Tigecycline or Tigecycline hydrochloride are used, then chemical and physical stability is improved, but water solubility is insufficient for effective pharmaceutical formulation
Solution Approach 1:
The patent applies parameter changes by modifying the crystalline structure through specific solvent selection (acetonitrile, ethyl acetate, or their mixtures) and controlled crystallization conditions (temperature range from room temperature to boiling point, stirring rates). These parameter changes result in a new crystalline form C of Tigecycline dihydrochloride that simultaneously achieves high water solubility (56.2-69.6 mg/mL) and thermodynamic stability, resolving the contradiction between stability and solubility that plagued previous formulations.
2Quantity of substance
If amorphous Tigecycline dihydrochloride is used, then water solubility is improved, but chemical and physical stability deteriorates
Solution Approach 1:
The patent employs phase transitions by inducing controlled crystallization from a supersaturated solution or slurry state to form stable crystalline structures. Through systematic crystallization from acetonitrile-based solvents under controlled conditions, the amorphous form is transformed into crystalline form C, which maintains high solubility while achieving the thermodynamic stability required for pharmaceutical storage and handling.
3Quantity of substance
If Tigecycline is dissolved and lyophilized to improve solubility, then water solubility is improved, but the formulation process complexity increases
Solution Approach 1:
The patent extracts the solubility enhancement directly at the crystalline solid state level rather than requiring post-dissolution processing. By incorporating the solubility-improving crystalline structure into the final solid form through direct crystallization from acetonitrile-based solvents, the need for complex lyophilization equipment and multi-step formulation processes is eliminated, simplifying manufacturing while maintaining high water solubility.
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
Crystalline form C of Tigecycline dihydrochloride exhibits the highest water solubility and thermodynamic stability, making it an ideal intermediate for anti-infective medicament preparation, with improved filterability and resistance to degradation, thus addressing the limitations of existing forms.
Implementation Method 1
stirring the suspension at a temperature ranging from room temperature to the boiling point of the used solvent or solvent mixture; isolating crystalline form C of Tigecycline dihydrochloride
Data Source
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AI summary
The present invention relates to crystalline form C of Tigecycline dihydrochloride and to methods for the preparation of the same. Furthermore the present invention relates to the use of crystalline form C of Tigecycline dihydrochloride as an intermediate for the preparation of an anti-infective medicament. Moreover the present invention relates to pharmaceutical compositions comprising crystalline form C of Tigecycline dihydrochloride in an effective amount and to the use of crystalline form C of Tigecycline dihydrochloride as an anti-infective medicament.