Conversion of modification D to modification A of doxazosin mesylate

US6500830B1 · kind B1 · utility

Assignee

• Knoll, Inc. · DE

Inventors

• Peter Klein · Itzehoe, DE
• Marco Thyes
• Dieter Hix · Großkarlbach, DE

Key dates

• Filing date: Jul 3, 2000
• Grant date: Dec 31, 2002
• Expiry date: Jul 3, 2020

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61P9/12
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing doxazosin mesylate in modification A which comprises dissolving doxazosin with methanesulfonic acid in methanol or a mixture of an aprotic, polar organic solvent and methanol, removing any turbidity from the resulting solution, and stirring the resulting clear solution until no further precipitate separates out, removing, washing with methanol, heating the precipitate in the moist state in ethanol and, after cooling, isolating the resulting product is described.