An official website of the United States government
Here's how you know
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Fig. 2. Number of drug substance patents containing CyPr, CyBu, oxetane, azetidine and BCP substructures filed between 2009 and 2019.28 β-Lactones and β-lactams were excluded from the analysis.