Anhydrous Lactate Salt Crystallization via Dynamic Temperature Control

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Solution Overview

Problem

There is a lack of methods for effectively preparing anhydrous lactate salts of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide, which are valuable for their pharmacological properties as histone deacetylase inhibitors, as previous descriptions do not provide specific protocols for these salts or their preparation.

Innovation Solution

A method involving dissolving or suspending the free base of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide in a solvent and treating it with a salt-forming agent, such as lactic acid, at controlled temperatures to precipitate the anhydrous lactate salt, while varying parameters like temperature and solvent composition to achieve crystalline forms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If no specific salt preparation method is provided (as in prior art), then the compound can be used for its pharmacological properties, but there is a lack of effective preparation methods for anhydrous lactate salts with high crystallinity and stability

Engineering Contradiction:
Improvecrystallinity and stability of lactate saltVSAvoidavailability of preparation method
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by systematically varying temperature, solvent composition, and pH conditions during salt formation to achieve the desired anhydrous lactate salt with high crystallinity. Specific parameters include controlling temperature ranges (e.g., 0-25°C for crystallization), adjusting solvent ratios (e.g., ethanol-water mixtures), and maintaining specific pH levels to optimize salt precipitation and crystallization.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions by controlling the transition from dissolved state to crystalline precipitate through temperature changes and solvent evaporation. The process involves heating to dissolve the free base, then cooling to induce crystallization of the anhydrous lactate salt, effectively using thermal phase transitions to achieve high crystallinity and purity.

Inventive Principle:
Principle #36Phase transitions

2Reliability

If conventional salt preparation methods are used, then general salt formation is possible, but specific protocols for anhydrous lactate salts are not provided, resulting in inconsistent crystallinity and stability

Engineering Contradiction:
Improveconsistency of salt preparationVSAvoidcomplexity of preparation protocol
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-determining optimal conditions for salt formation based on solubility studies and preliminary experiments. The method includes pre-selecting appropriate solvents (e.g., ethanol, isopropanol, or ethanol-water mixtures), pre-establishing temperature profiles, and pre-calculating stoichiometric ratios of free base to lactic acid to ensure consistent anhydrous salt formation without requiring complex real-time adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by introducing a mediating solvent system that facilitates controlled salt formation. The solvent acts as an intermediary medium that allows gradual precipitation and crystallization of the anhydrous lactate salt, enabling consistent results while simplifying the overall process through a well-defined solvent-mediated mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If salt formation is performed without controlled temperature and solvent parameters, then the process is simple, but the resulting salt lacks high crystallinity and pharmacological efficacy

Engineering Contradiction:
Improvepharmacological efficacy of saltVSAvoidtemperature control during preparation
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent applies dynamics by implementing a dynamic temperature profile during salt formation. The process involves initial heating to dissolve the free base and lactic acid, maintaining a specific temperature range during reaction, then controlled cooling to induce crystallization. This dynamic temperature control ensures high crystallinity and pharmacological efficacy while managing the complexity through a standardized protocol.

Inventive Principle:
Principle #15Dynamics

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

This method allows for the consistent preparation of anhydrous lactate salts with high crystallinity and stability, enhancing their pharmacological efficacy and usability in therapeutic applications.

Implementation Method 1

treating the N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide free base at an appropriate temperature with a salt forming agent, wherein the salt forming agent is selected from the group consisting of suppliers of hydrochloride, lactate, maleate, mesylate, tartarate, acetate, benzoate, citrate, fumarate, gentisate, malate, malonate, oxalate, phosphate, propionate, sulfate, succinate, sodium, potassium, calcium or zinc ions

Methodology Applied
Scientific EffectAcid-base neutralization: Chemical Bonding

Implementation Method 2

cooling the reaction mixture; and optionally (e) isolating the precipitated hydrochloride salt

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 3

stirring the reaction mixture for a time sufficient to cause precipitation of the hydrochloride salt

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Data Source

PatentEP2032532B8Process for making salts of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide
Publication Date: 2015.07.01 NOVARTIS AG

AI summary

Salts of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide are prepared by various methods.