Granted Patent
Utility
US 4,973,304 · App. 07/477,128
Device for sustained release of active substance
Inventors:
Neil B. Graham, Ernst R. Huehns, Marion E. McNeill
Patented Case
View Patent ↗
Granted: Nov 27, 1990
Filed: Feb 7, 1990
Inventors
Neil B. Graham
Ernst R. Huehns
Marion E. McNeill
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT CORPORATION
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.