Patents by Inventor Don Wha Lee

Don Wha Lee has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Process for preparing cyclosporin A
    Patent number: 5874572
    Abstract: A process for the isolation of cyclosporin A comprising the steps of: adding a lower alkanol solvent to a culture fluid of a mutant of Tolypocladium inflatum to form a mixture, filtering the mixture to form an extract, transferring the extract to methylene chloride as a solvent therefor, and column chromatographing the resultant product on silica gel.
    Type: Grant
    Filed: June 16, 1997
    Date of Patent: February 23, 1999
    Assignee: Chong Kun Dang Corp.
    Inventors: Jung Woo Kim, Nam Hee Choi, Sang Chul Lee, Gang Sun Choi, Yun Beom Ham, Don Wha Lee, Kyeong Bok Min
  • Process for manufacturing clavulanic acid salt
    Patent number: 5734048
    Abstract: According to the present invention, a process for manufacturing alkali metal salt of clavulanic acid wherein impure clavulanic acid in aqueous solution is extracted by a solvent mixture of ketone and alkyl acetate under acidic condition, treated in a conventional manner, and a solution of alkali metal salt of alkanoic acid dissolved in ketone or alkanol solvent is added to obtain pure alkali metal salt of clavulanic acid is provided.Since the process according to the present invention omits a step of formation of amine salt, an economic and simple method for manufacturing alkali metal salt of clavulanic acid in a high yield without excessive use of solvent is provided.
    Type: Grant
    Filed: November 7, 1995
    Date of Patent: March 31, 1998
    Assignee: Chong Kun Dang Corp.
    Inventors: Jung Woo Kim, Nam Hee Choi, Gang Sun Choi, Don Wha Lee