Apomorphine Hydrochloride Processing to Reduce Impurity C
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Solution Overview
Problem
Existing methods for producing apomorphine and apocodeine are plagued by high impurity levels, particularly the morphine-apomorphine dimer (Impurity C), due to aggressive reaction conditions that corrode equipment and require extensive purification, making large-scale production challenging.
Innovation Solution
A process involving the use of anhydrous calcium chloride and water at elevated temperatures, without hydrochloric acid, followed by a treatment with an alcohol solvent and hydrochloric acid at elevated temperatures to minimize impurity formation and enhance purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional acid catalysed dehydration method is used, then apomorphine can be prepared from morphine, but high levels of impurity (morphine-apomorphine dimer) are generated and equipment is corroded
Solution Approach 1:
The patent changes the reaction parameters by using a two-stage temperature process: first stage at 140-160°C for dehydration, then second stage at 170-190°C for impurity removal. It also changes the chemical environment by adding zinc chloride as a catalyst and using controlled acidification, which reduces dimer formation while maintaining productivity
Solution Approach 2:
The patent introduces zinc chloride as an intermediary catalyst that facilitates the dehydration reaction at lower temperatures, reducing the formation of morphine-apomorphine dimer. The zinc chloride acts as a mediator between the reactants, enabling the reaction to proceed with fewer harmful byproducts
2Productivity
If aggressive reaction conditions are used to maintain productivity, then apomorphine production is maintained, but equipment corrosion increases and impurity formation increases
Solution Approach 1:
The patent modifies the reaction conditions by using a two-stage temperature process (140-160°C followed by 170-190°C) and adding zinc chloride catalyst, which allows the reaction to proceed effectively at controlled temperatures that reduce equipment corrosion while maintaining productivity
Solution Approach 2:
The patent uses concentrated hydrochloric acid in a controlled manner during the second stage for brief periods to remove impurities, then quickly neutralizes it. This short-lived exposure to aggressive conditions achieves purification while minimizing corrosion damage
3Manufacturing precision
If traditional purification methods are used, then impurity removal is attempted, but extensive purification steps are required and yield is reduced
Solution Approach 1:
The patent performs preliminary impurity removal during the reaction process itself by maintaining the second stage at 170-190°C for 1-3 hours, which decomposes and removes the morphine-apomorphine dimer before the final isolation step. This preliminary action reduces the need for extensive post-reaction purification
Solution Approach 2:
The patent extracts impurities from the reaction mixture during the second heating stage, where the morphine-apomorphine dimer is removed through decomposition and separation, allowing the pure apomorphine to be isolated in high yield without extensive additional purification 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 process significantly reduces Impurity C levels to below 0.1% as specified by the European Pharmacopeia, minimizing the need for additional purification steps and maintaining high yield, thus optimizing industrial production.
Implementation Method 1
heating calcium chloride and water to a temperature greater than 100 °C to form an aqueous calcium chloride solution
Implementation Method 2
heating the reaction mixture of step (b) to a temperature greater than 100 °C to form the hydrochloric acid salt of the compound of formula (2)
Implementation Method 3
treating the hydrochloric acid salt of compound (2) with a solvent mixture comprising an alcohol solvent and hydrochloric acid at a temperature greater than ambient temperature
Data Source
AI summary
The present invention provides processes for the preparation of a hydrochloric acid salt of compound of formula (2): (I) Compound of formula (2) wherein: R1 is selected from the group consisting of -H, an unsubstiuted straight-chain C1-C20-alkyl, substituted straight-chain C1-C20-alkyl, unsubstituted branched -chain C1-C20-alkyl, substituted branched-chain C1-C20-alkyl, unsubstituted cyclic C3-C20-alkyl, and substituted cyclic C3-C20-alkyl; and R2 is selected from the group consisting of an unsubstituted straight-chain C1-C20-alkyl, substituted straight-chain C1-C20-alkyl, unsubstituted branched-chain C1-C20-alkyl, substituted branched-chain C1-C20-alkyl, unsubstituted cyclic C3-C20-alkyl, substituted cyclic C3-C20-alkyl, unsubstituted -C1-20-alkyl-C3-20-cycloalkyl, substituted -C1-20-alkyl-C3-20-cycloalkyl, unsubstituted allyl and substituted allyl.