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US 6,855,813 B2Granted
Process for the preparation of azithromycin monohydrate
AssigneeAlembic Limited
InventorSrinivasan Rengaraju
Life of this patent
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Abstract
The invention relates to a process for making Azithromycin crystals using a number of process steps that avoids the use of cumbersome and/or inefficient extraction and/or isolation procedures.
Claims12
A process for making Azithromycin monohydrate crystals, said process comprising the steps of:
- (a) dissolving 9-Deoxo-9a-aza-9a-homoerythromycin A in acetonitrile, to form a solution;
- (b) adding formic acid and formaldehyde to said solution;
- (c) refluxing said solution to form a reaction mixture;
- (d) adjusting the pH of said reaction mixture from about 10 to about 11 with alkaline solution;
- (e) optionally filtering the pH adjusted reaction mixture of step (d);
- (f) adding water to said reaction mixture to precipitate said Azithromycin monohydrate crystals directly from said reaction mixture;
- (g) filtering out said Azithromycin monohydrate crystals precipitated in said step (f);
- and
- (h) drying said Azithromycin monohydrate crystals,
- wherein said process is conducted without an extraction step.
7 more elements
A process for making Azithromycin monohydrate crystals, said process comprising the steps of:
- (a) dissolving 9-Deoxo-9a-aza-9a-homoerythromycin A in acetonitrile to form a solution;
- (b) adding formic acid and formaldehyde to said solution;
- (c) refluxing said solution to form a reaction mixture;
- (d) adjusting the pH of said reaction mixture from about 10 about 11 with alkaline solution;
- (e) optionally filtering the pH adjusted reaction mixture of step (d);
- and
- (f) adding water to said reaction mixture to precipitate said Azithromycin monohydrate crystals directly from said reaction mixture,
- wherein said process is conducted without an extraction step.
5 more elements
A process for making Azithromycin monohydrate, said process comprising the steps of:
- (a) reductively methylating, in a reaction mixture, 9-Deoxo-9a-aza-9a-homoerythromycin A dissolved in acetonitrile, and
- (b) adding water to said reaction mixture to precipitate said Azithromycin monohydrate directly from said reaction mixture,
- wherein said process is conducted without an extraction step.
Dependencies are inferred from the claim text.