Topic for a public choice economic case study

Guaifenesin - Wikipedia, the free encyclopedia: "Although previously deemed 'Generally Regarded as Safe' in its original approval, the drug received a New Drug Application for the extended-release version, which won approval on July 12, 2002. Because of this, the FDA then issued letters to other manufacturers of timed-release guaifenesin to stop marketing their unapproved versions, leaving Adams Respiratory Therapeutics in control of the market."