Crystalline Zn-DTPA Forms for Stable Oral Formulations
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Solution Overview
Problem
Current methods for producing trisodium zinc diethylene triamine pentaacetic acid (Zn-DTPA) result in an amorphous, hygroscopic product that is difficult to handle and unstable under atmospheric conditions, making it unsuitable for oral pharmaceutical formulations.
Innovation Solution
The production of Zn-DTPA in crystalline forms, specifically Forms I and II, which exhibit reduced hygroscopicity and enhanced chemical stability, achieved through methods involving precipitation with methanol or azeotropic distillation with n-butanol, resulting in a stable powder with improved handling properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the standard synthesis method is used to produce Zn-DTPA, then the complex formation is satisfactory, but the product is amorphous and highly hygroscopic, making it difficult to handle
Solution Approach 1:
The invention changes the physical-chemical parameters of the product by controlling crystallization conditions (solvent type, temperature, concentration) to transform the amorphous hygroscopic product into a crystalline form with reduced hygroscopicity and improved handling properties
Solution Approach 2:
The invention utilizes phase transition from amorphous to crystalline state through controlled crystallization processes, where the product transitions from a disordered amorphous phase to an ordered crystalline phase, fundamentally changing its physical properties including hygroscopicity and stability
2Productivity
If the product is concentrated by distilling off water, then isolation is achieved, but the resulting amorphous product absorbs more than 10 wt% water within 24 hours
Solution Approach 1:
The invention changes the isolation parameters by replacing water removal with organic solvent addition and controlled crystallization, transforming the isolation mechanism from evaporation-based to crystallization-based, thereby producing a stable crystalline product
Solution Approach 2:
The invention introduces organic solvents (methanol, ethanol, acetone, or n-butanol) as intermediaries to facilitate product isolation and crystallization, where these solvents mediate the formation of stable crystalline structures with reduced water absorption
3Adaptability or versatility
If Zn-DTPA is exposed to humidity for oral formulation, then administration route is expanded, but the product melts due to hygroscopy
Solution Approach 1:
The invention changes the physical parameters of Zn-DTPA by inducing crystallization under controlled conditions, transforming it from an amorphous hygroscopic substance to a crystalline form with enhanced stability that can withstand oral formulation requirements
Solution Approach 2:
The invention applies preliminary anti-action by pre-crystallizing the product in a stable form before exposure to humid conditions during oral formulation, thereby preventing the melting that would otherwise occur due to hygroscopic water absorption
4Reliability
If crystalline forms are produced through precipitation or azeotropic distillation, then hygroscopicity is reduced, but additional process steps are required
Solution Approach 1:
The invention utilizes phase transitions (precipitation and azeotropic distillation) to produce crystalline forms with reduced hygroscopicity, where the phase change from solution to crystal provides inherent stability without requiring complex additional processing steps
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 of Zn-DTPA demonstrate significantly reduced water absorption, maintaining stability even at high humidity, allowing for the development of reliable oral pharmaceutical formulations and expanded applications.
Implementation Method 1
precipitation with methanol
Implementation Method 2
azeotropic distillation with n-butanol
Data Source
Figure 1~2
AI summary
The invention relates to the production of zinc trisodium pentetic acid (Zn-DTPA) and to new crystalline forms of said salt.