Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

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.

View full-text article in PMC

. 2012 Dec 5;7(12):e49470. doi: 10.1371/journal.pone.0049470

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2012 Kapczynski et al

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.

PMC Copyright notice

Based on the 432 new molecular entities (with at least one patent) approved by the U.S. Food and Drug Administration between 1985 and 2005. Categories are based on authors' coding of the claims from the 1304 patents (1261 distinct patents) associated with these drugs. “PIPES” refers to Polymorph, Isomer, Prodrug, Ester, and Salt claims. “Independent” secondary patents are those with no chemical compound claims. The horizontal axis is drug approval year. The vertical axis measures the moving average of the share of drugs in an approval year with at least one patent in a category.