Ibandronate Sodium Monohydrate Polymorph B Preparation Process
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Solution Overview
Problem
Current processes for preparing ibandronate sodium monohydrate are inefficient, hazardous, and costly, with low yields and impurities, and lack environmentally friendly conditions, particularly in the production of crystalline polymorphs like polymorph B.
Innovation Solution
A process involving bisphosphorylation of 3-(N-methyl-N-pentylamino)propionic acid with phosphorous acid and a halophosphorus compound in methanesulfonic acid, followed by hydrolysis, decolorization, filtration, and recrystallization in a mixture of alkanol and polar solvent, to produce high-purity crystalline ibandronate sodium monosodium salt monohydrate polymorph B.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If concentrated hydrochloric acid is used for hydrolysis, then the reaction proceeds effectively, but the process becomes toxic, corrosive, and environmentally harmful
Solution Approach 1:
The patent uses semi-concentrated hydrochloric acid (approximately 6M) as an intermediary substance instead of concentrated hydrochloric acid. This intermediary concentration provides sufficient hydrolysis effectiveness while reducing the harmful effects of toxicity and corrosiveness. The semi-concentrated acid acts as a mediator that balances reaction efficiency with safety and environmental considerations.
2Ease of operation
If chlorobenzene is used as reaction solvent, then the reaction components are solubilized, but the process becomes environmentally harmful and potentially carcinogenic
Solution Approach 1:
The patent replaces the harmful chlorobenzene solvent with water, which is inexpensive, non-toxic, and environmentally friendly. Although water may not solubilize all reaction components as effectively as chlorobenzene, the use of water aligns with green chemistry principles and eliminates the environmental and health hazards associated with chlorobenzene. This substitution prioritizes safety and environmental protection over optimal solubility.
3Ease of operation
If methanesulfonic acid is used to solubilize reaction components, then the mixture remains stirrable, but the reaction becomes self-heating and unsafe at large scale
Solution Approach 1:
The patent removes methanesulfonic acid from the reaction system entirely, extracting this problematic substance from the process. By eliminating methanesulfonic acid, the patent avoids the self-heating issue that occurs when it reacts with phosphorus trichloride at temperatures above 85°C. The reaction mixture's stirrability is maintained through alternative means, such as using water as the solvent system and controlling reaction conditions.
4Manufacturing precision
If ion exchange resin chromatography is used for isolation, then ibandronic acid is purified, but the process becomes difficult and time-consuming on industrial scale
Solution Approach 1:
The patent replaces the complex ion exchange resin chromatography process with a simpler, more scalable method using water as the isolation medium. Instead of requiring expensive ion exchange resins and complex chromatographic equipment, the patent utilizes the solubility characteristics of ibandronic acid in water to achieve purification through filtration and crystallization. This approach maintains product purity while dramatically reducing processing time and operational difficulty for industrial-scale production.
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 process achieves high yield and purity of ibandronate sodium monohydrate polymorph B in environmentally friendly conditions, reducing costs and operational hazards, and is scalable for industrial production while maintaining pharmaceutical standards.
Implementation Method 1
The reaction starts as a two-phase melt which gradually thickens, resulting in a semi-solid
Implementation Method 2
the reaction mixture by refluxing in concentrated hydrochloric acid
Implementation Method 3
Upon cooling, the semi-solid forms a brittle glass
Data Source
AI summary
The present invention relates to an improved process for the preparation of 3-(N-methyl-N- pentyl)amino-1-hydroxypropane-1,1-diphosphonic acid, monosodium salt, or its derivatives, in substantially pure crystalline form.