Granted Patent
Utility
US 4,756,844 · App. 06/947,111
Controlled-release composition having a membrane comprising submicron particles
Inventors:
Wilhelm E. Walles, Donald L. Tomkinson
Patented Case
View Patent ↗
Granted: Jul 12, 1988
Filed: Dec 29, 1986
Inventors
Wilhelm E. Walles
Donald L. Tomkinson
Assignee (at issue)
THE DOW CHEMICAL COMPANY
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.