Lercanidipine Hydrochloride Purification via Solvent Crystallization
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Solution Overview
Problem
Existing processes for preparing lercanidipine hydrochloride often result in the production of impurities, particularly 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)pyridine-3,5-dicarboxylic acid 2-[N-(3,3-diphenyl propyl)-N-methylamino]-1,1-dimethyl ethyl propyl diester, which are difficult to remove and affect the purity of the final product.
Innovation Solution
A process involving the dissolution of lercanidipine hydrochloride in an alcohol-containing solvent, followed by the addition of an aliphatic ester-containing solvent, and subsequent recovery of substantially pure lercanidipine hydrochloride in polymorph form V, characterized by specific X-ray diffraction peaks and a differential scanning calorimetric thermogram, effectively reduces impurities and enhances purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional processes are used to prepare lercanidipine hydrochloride, then the production process is established, but impurities are generated and purification becomes difficult
Solution Approach 1:
The patent changes the physical-chemical parameters of the system by utilizing specific solvent combinations (alcohol-containing solvent and aliphatic ester-containing solvent) and controlling temperature conditions to achieve selective crystallization. This parameter change enables the formation of polymorph form V with high purity, effectively resolving the impurity removal difficulty without requiring complex chromatographic purification processes.
Solution Approach 2:
The patent employs phase transition principles through controlled crystallization processes. By dissolving lercanidipine hydrochloride in alcohol-containing solvent and then adding aliphatic ester-containing solvent, the system undergoes phase separation and crystallization to form pure polymorph form V. This phase transition approach enables effective purification by exploiting differences in solubility and crystallization behavior between the target compound and impurities.
2Manufacturing precision
If multiple purification steps are implemented, then impurity removal improves, but process complexity and time increase
Solution Approach 1:
The patent extracts and removes impurities through selective crystallization by taking out the target compound from the impurity mixture in a purified form. By controlling the crystallization process to favor polymorph form V, the method selectively extracts the pure compound while leaving impurities in the mother liquor, achieving high purity without requiring multiple complex purification steps.
Solution Approach 2:
The patent uses solvent systems as intermediaries to facilitate purification. The alcohol-containing solvent and aliphatic ester-containing solvent act as intermediaries that enable selective dissolution and crystallization. These solvent intermediaries allow the target compound to be separated from impurities through controlled phase transitions, simplifying the overall purification process while maintaining high manufacturing precision.
3Productivity
If conventional crystallization methods are used, then product recovery is achieved, but polymorph control and purity are insufficient
Solution Approach 1:
The patent applies parameter changes by specifically controlling solvent composition ratios, temperature profiles, and addition rates to favor the formation of polymorph form V. By adjusting these parameters, the method achieves both high product recovery and high polymorph purity, resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent employs preliminary action by pre-dissolving lercanidipine hydrochloride in alcohol-containing solvent before adding the aliphatic ester-containing solvent. This preliminary dissolution step ensures uniform distribution and controlled nucleation, leading to formation of pure polymorph form V while maintaining high recovery rates. The preliminary action prevents premature crystallization and ensures controlled polymer formation.
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 yields a substantially pure lercanidipine hydrochloride with improved efficiency, using inexpensive reagents and minimizing waste and impurities, resulting in a high-purity product suitable for pharmaceutical applications.
Implementation Method 1
dissolving lercanidipine hydrochloride in an alcohol-containing solvent
Implementation Method 2
adding an aliphatic ester-containing solvent to the solution
Implementation Method 3
recovery of substantially pure lercanidipine hydrochloride in polymorph form V, characterized by specific X-ray diffraction peaks and a differential scanning calorimetric thermogram
Data Source
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AI summary
Processes for the purification of lercanidipine hydrochloride are provided which uses a binary system of an alcohol-containing solvent such as methanol and an aliphatic ester-containing solvent such as isopropyl acetate. Processes for the preparation of substantially amorphous lercanidipine hydrochloride are also provided. Also provided is lercanidipine hydrochloride substantially in polymorph form V.