Food and Drug Administration (FDA) has added the first four bulk drug substances to the 503B Bulks List to provide Americans access to compounded medicines when they cannot be met by an FDA-approved drug. The first four added drug substances for topical use that may be used for compounding by outsourcing facilities include: 

  • diphenylcyclopropenone, 
  • glycolic acid,  
  • squaric acid dibutyl ester, and  
  • trichloroacetic acid.  

More details are available in the Drugs section of the FDA website,