Patents by Inventor Alexander H. T. Chu

Alexander H. T. Chu 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).

  • Patent number: 5861110
    Abstract: A method for production of high specific surface area silica gel by hydrolysis of silicon tetrahalide, wherein a solution of silicon tetrahalide in a non-reactive solvent such as alcohol is mixed with water to produce silica gel having a high surface area and narrow pore diameter distribution especially suited for use as normal phase packing material in high performance chromatography columns. The water contains fluoride ions if the halide is chloride. Reverse phase packing material can be prepared by reacting the normal phase silica gel with organochlorosilanes to prepare bonded reverse phase material for use in high performance liquid chromotagraphy systems.
    Type: Grant
    Filed: July 10, 1992
    Date of Patent: January 19, 1999
    Inventors: Paul C. Chieng, Deborah J. Brame, Alexander H. T. Chu
  • Patent number: 5616595
    Abstract: A novel process for recovering water insoluble compounds from a fermentation broth includes sequential steps of concentrating, solubilizing and diafiltering the compound of interest, all through a single closed recirculation system to recover the compound for further downstream purification.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: April 1, 1997
    Assignee: Abbott Laboratories
    Inventors: Alexander H. T. Chu, Gene P. Wloch
  • Patent number: 5574135
    Abstract: A process for the manufacture of vancomycin which does not require preparation of a phosphate intermediate. The process consists of passing a vancomycin broth through a suitable adsorbent, followed by passing the vancomycin through a second adsorbent, producing a purified vancomycin. Purified vancomycin is then crystallized from the solution by adding a base solution that imparts a pH of above about 9.0 to about 9.5 to the purified vancomycin. The crystallized vancomycin is separated from the solution, dissolved in solution and recrystallized by adding a base solution which imparts a pH of above about 9.0 to about 9.5 to the dissolved solution. The recrystallized vancomycin is dissolved and titrated with hydrochloric acid. Vancomycin. HCl is then precipitated from the solution using an organic solvent.
    Type: Grant
    Filed: February 10, 1995
    Date of Patent: November 12, 1996
    Assignee: Abbott Laboratories
    Inventor: Alexander H. T. Chu
  • Patent number: 5258495
    Abstract: A process for the manufacture of vancomycin.HCl which does not require preparation of a phosphate intermediate. The process consists of loading a vancomycin onto a suitable adsorbent and eluting the vancomycin solution therefrom with an ammonium solvent followed by loading the vancomycin solution onto a suitable adsorbent and eluting the purified, vancomycin solution therefrom with a solvent of alcohol and acid. The purified vancomycin is then crystallized from the solution by combining the solution with a sufficient amount of NH.sub.4 Cl to provide a pH of about 2.0 to about 3.5. The crystals are then dissolved in solution. The dissolved solution is combined with acid and the vancomycin recrystallizes from the solution.
    Type: Grant
    Filed: April 27, 1992
    Date of Patent: November 2, 1993
    Assignee: Abbott Laboratories
    Inventor: Alexander H. T. Chu
  • Patent number: 5158758
    Abstract: A method for production of high specific surface area silica gel by hydrolysis of silicon tetrahalide, wherein a solution of silicon tetrahalide in a non-reactive solvent such as alcohol is mixed with water to produce silica gel having a high surface area and narrow pore diameter distribution especially suited for use as normal phase packing material in high performance chromatography columns. The water contains fluoride ions if the halide is chloride. Reverse phase packing material can be prepared by reacting the normal phase silica gel with organochlorosilanes to prepare bonded reverse phase material for use in high performance liquid chromotagraphy systems.
    Type: Grant
    Filed: April 24, 1989
    Date of Patent: October 27, 1992
    Assignee: International Minerals & Chemical Corp.
    Inventors: Paul C. Chieng, Deborah J. Brame, Alexander H. T. Chu
  • Patent number: 5149784
    Abstract: A process for the manufacture of vancomycin which does not require preparation of a phosphate intermediate. The process consists of loading a vancomycin onto a suitable adsorbent and eluting the vancomycin solution therefrom with an ammonium solvent followed by loading the solution onto a second adsorbent and eluting the purified, vancomycin therefrom with a solvent of alcohol and acid. The purified vancomycin is then crystallized by adding a base solution in an amount sufficient to raise the pH of the vancomycin/base solution to a pH of about 9.5 to 10.5 followed by the addition of an organic solvent such as methanol. The crystallized vancomycin is then reslurried in an aqueous solution and then recrystallized by adding a base solution in an amount sufficient to raise the pH to about 9.5 to about 10.5, followed by the addition of an organic solvent such as methanol. The recrystallized vancomycin is dissolved and titrated with hydrochloric acid to a pH of about 3.0 to 3.5.
    Type: Grant
    Filed: July 10, 1990
    Date of Patent: September 22, 1992
    Assignee: Abbott Laboratories
    Inventor: Alexander H. T. Chu
  • Patent number: 5041374
    Abstract: Polyether antibiotic material is liberated from agglomerates containing a lipid material and the polyether antibiotic material by separating the polyether antibiotic from the lipid through formation of an acid salt of the lipid and a desired acid salt of the polyether antibiotic. The agglomerates can be formed during fermentation or produced by adding lipids afterwards.
    Type: Grant
    Filed: May 29, 1986
    Date of Patent: August 20, 1991
    Assignee: International Minerals & Chemical Corp.
    Inventors: Alexander H. T. Chu, Robert J. Urban
  • Patent number: 4871866
    Abstract: A process for purifying lysocellin which comprises mixing lysocellin solids with sufficient halogen acid to convert fatty acid ester salt impurities into water-soluble metal halogen salts and water-insoluble free fatty acids and to convert lysocellin salts into water-soluble metal halogen salts and water-insoluble lysocellin acid, separating the halogen salts from the lysocellin acid and fatty acid solids, mixing the lysocellin acid and fatty acid solids with sufficient caustic reagent to convert free fatty acids into water-soluble alkali metal salts and to convert lysocellin acid into a water-insoluble alkali metal lysocellin salts, and separating the water-soluble fatty acid alkali metal salts from the alkali metal lysocellin solids.
    Type: Grant
    Filed: August 24, 1987
    Date of Patent: October 3, 1989
    Assignee: Pitman-Moore, Inc.
    Inventors: Alexander H. T. Chu, M. James Levi