Patent 7598222 was granted and assigned to Eli Lilly and Company on October, 2009 by the United States Patent and Trademark Office.
Disclosed is a method of preparing a GLP-1 compound that is soluble in aqueous solution at pH 7.4 from a GLP-1 compound that is substantially insoluble in aqueous solution at pH 7.4. The insoluble GLP-1 compound is dissolved in aqueous base or in aqueous acid to form a GLP-1 solution. The GLP-1 solution is then neutralized to a pH at which substantially no amino acid racemization of the GLP-1 compounds occurs, after which the soluble GLP-1 compound is isolated from the neutralized solution.