Verapamil Hydrochloride Crystalline Forms Stability
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Solution Overview
Problem
Current methods for producing (R)-(+)-verapamil hydrochloride lack stable and pure crystalline forms suitable for pharmaceutical applications, affecting its solubility, stability, and handling during processing.
Innovation Solution
Development of novel crystalline forms, specifically Form E and Form T of (R)-(+)-verapamil hydrochloride, through a crystallization process involving dissolution in suitable solvents like ethyl acetate and toluene, followed by cooling and drying, which yield specific X-ray diffraction patterns and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional production methods are used for (R)-(+)-verapamil hydrochloride, then the drug substance can be produced, but the crystalline forms lack stability and purity suitable for pharmaceutical applications
Solution Approach 1:
The patent applies parameter changes by optimizing crystallization conditions including solvent selection (ethyl acetate, toluene, or their mixtures), temperature control (cooling from dissolution temperature to room temperature or lower), and pH adjustment (maintaining pH 3-5 during crystallization). These parameter modifications enable the formation of stable crystalline forms with defined X-ray diffraction patterns and improved storage stability while maintaining high purity.
Solution Approach 2:
The patent utilizes phase transitions through the crystallization process where (R)-(+)-verapamil hydrochloride transitions from dissolved state in hot solvent to crystalline solid form upon cooling. The specific crystallization conditions promote formation of stable polymorphic forms with characteristic X-ray diffraction patterns, ensuring both stability and purity required for pharmaceutical applications.
2Ease of operation
If conventional production methods are used for (R)-(+)-verapamil hydrochloride, then the drug substance can be produced, but the solubility and handling characteristics are insufficient for pharmaceutical processing
Solution Approach 1:
The patent improves handling characteristics and solubility by optimizing crystallization parameters including solvent choice (ethyl acetate, toluene, or mixtures), temperature profile (dissolution at elevated temperature followed by controlled cooling), and pH control (maintaining pH 3-5). These changes produce crystalline forms with improved flow properties, reduced hygroscopicity, and enhanced solubility characteristics suitable for pharmaceutical processing operations.
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 novel crystalline forms exhibit enhanced storage stability, solubility, and purity, making them suitable for pharmaceutical use in treating conditions related to specific receptors and ion channels, with reduced impurity levels and improved handling characteristics.
Implementation Method 1
Development of novel crystalline forms, specifically Form E and Form T of (R)-(+)-verapamil hydrochloride, through a crystallization process involving dissolution in suitable solvents like ethyl acetate and toluene, followed by cooling and drying
Implementation Method 2
through a crystallization process involving dissolution in suitable solvents like ethyl acetate and toluene, followed by cooling and drying
Data Source
AI summary
Novel crystal forms of (R)-(+)-verapamil hydrochloride are disclosed.