"A very good indication of the success of the prodrug approach can be obtained by examining the prevalence of prodrugs on the market. It might come as a surprise to many people that currently approximately 10% of all globally marketed medicines can be classified as prodrugs, and in 2008 alone,
33% of all approved small-molecular-weight drugs were prodrugs (Rautio, 2010; Stella, 2010). Despite these impressive numbers,
we have only begun to appreciate the full potential of the prodrug approach in modern drug development, and many novel prodrug innovations await discovery. "
from your link
http://m.pharmrev.aspetjournals.org/content/63/3/750.full
Go Prurisol! Go CTIX!