Distillation Method For The Purification Of Sevoflurane And The Maintenance Of Certain Equipment That May Be Used In The Distillation Process

a technology of sevoflurane and distillation method, which is applied in the direction of cleaning using liquids, ether preparation, organic chemistry, etc., can solve the problems of insufficient purification of products, difficult separation/disproportionation of products from sevoflurane by distillation, and added expense for their use and disposal

Inactive Publication Date: 2009-11-05
HALOCARBON PROD CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011]Since the sevoflurane of the present invention is substantially free of impurities that may lead to decomposition, there is no need for special containers to store the se

Problems solved by technology

Many of these impurities can be removed by distillation, but it has been, disclosed in U.S. Pat. No. 5,684,211 that crude sevoflurane can decompose or disproportionate under distillative conditions and that, the product could not be adequately purified as a result of this decomposition/disproportionation.
It is difficult to separate this decomposition/disproportionation product from sevoflurane by distillation because their boiling points are very similar.
Potential drawbacks to the use of such agents, however, include added expense for their use and disposal, as well as the necessity t

Method used

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Embodiment Construction

[0029]The present invention provides an improved process for preparing commercial quantities of stable, pharmaceutically acceptable sevoflurane substantially free of impurities and without the use of decomposition suppression agents.

[0030]The phrase “substantially pure sevoflurane,” as used herein is sevoflurane which contains less than 300 ppm of total impurities, and less than 100 ppm of any individual impurity, in a preferred embodiment, the term “substantially pure sevoflurane” means sevoflurane which contains less than 100 ppm of total impurities, and most preferably less than 20 ppm of any individual impurity. Total impurities are defined as impurities not including water.

[0031]The term “stable” as used herein means that, the substantially pure sevoflurane remains substantially pure as herein defined for at least two years from the time of production at ambient temperature, or for at least three months at 40° C. Stability is achieved without the addition of sevoflurane decompo...

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Abstract

Processes for preparing commercial quantities of a stable, pharmaceutically acceptable sevoflurane substantially tree of impurities are claimed. In another embodiment, a process for removing reactive metal, salts from the surface of metallic equipment used in the distillation of sevoflurane and rendering a non-inert metallic surface of the metallic equipment inert.

Description

[0001]Sevoflurane is produced by several known methods. A commonly used method involves the reaction of formaldehyde (or a formaldehyde equivalent), hydrogen fluoride (HF), and hexafluoroisopropanol (HFIP). U.S. Pat. No. 4,250,334 describes a process in which HFIP is added to a mixture of a stoichiometric excess of paraformaldehyde and HF plus sufficient sulfuric acid to sequester most of the water formed in the reaction. WO 97 / 25303 describes a process for the production of sevoflurane in which essentially pure bis(fluoromethyl)ether (BFME) is allowed to react with HFIP and sulfuric acid. U.S. Pat. No. 6,469,219 describes a process in which HFIP and a formaldehyde equivalent are allowed to react with excess HF under distillative or extractive conditions in order to produce sevoflurane. Other synthetic routes generate a different impurity profile, but stilt require a final distillation in order to produce a pharmaceutically acceptable form of sevoflurane.[0002]In all of these proces...

Claims

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Application Information

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IPC IPC(8): C07C41/42B08B3/08
CPCC07C41/42C07C43/123
Inventor JONES, BARRYSWINSON, JOELMAZZELL, PAUL
Owner HALOCARBON PROD CORP
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