Patents by Inventor Hans E. Keller

Hans E. Keller 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).

  • Vitamin A compositions
    Patent number: 4254100
    Abstract: Microcrystalline vitamin A acetate dry free-flowing powders containing microcrystalline vitamin A acetate and a process for their preparation are disclosed.
    Type: Grant
    Filed: March 7, 1980
    Date of Patent: March 3, 1981
    Assignee: Hoffmann-La Roche Inc.
    Inventors: Hans E. Keller, Heinrich Klaeui