Granted Patent
Utility
US 5,292,517 · App. 07/840,875
pH sensitive, reversible gelling, copolymeric erodible drug delivery system
Inventor:
Nienyuan J. Chang
Patented Case
View Patent ↗
Granted: Mar 8, 1994
Filed: Feb 25, 1992
Inventor
Nienyuan J. Chang
Assignee (at issue)
Allergan, Inc.
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.