The US Food and Drug Administration (FDA) is calling for help in compiling a blacklist of sorts of drugs that should not be permitted to be compounded under the terms of the just-passed Drug Quality and Security Act (DQSA) of 2013.

Among the law's many provisions is one that allows FDA to establish a list of products that no federally regulated compounded pharmacy-also known as "outsourcing facilities"-can manufacture by virtue of their complexity.

Edit: Per FDA's FR Notice, it appears that FDA also wants this to apply to facilities regulated at the state level under 503A: "FDA intends to develop and publish a single list of drug products and categories of drug products that cannot be compounded and still qualify for any of the exemptions set forth in sections 503A and 503B because they present demonstrable difficulties for compounding." -- Editor

FDA has found that some products, and particularly those intended to be sterile, are especially challenging to manufacture. Some drugs in particular may be "reasonably likely to lead to an adverse effect on the safety or effectiveness of the drug or category of drugs," legislators wrote in the DQSA.

In general, difficult-to-compound drugs are characterized as such by virtue of the manufacturing processes' effects on their potency, purity, quality, consistency, and bioavailability. FDA has also highlighted the complexity of the manufacturing process itself, saying that the more steps a product requires to be made, the more opportunities there are for something to go wrong.

But while this fact makes conceptual sense, regulators now have a far more challenging task ahead of them: Figuring out which products belong on its compounding blacklist, formally known as "Drug Products that Present Demonstrable Difficulties for Compounding" and informally as a "difficult-to-compound" list.

In a Federal Register announcement on 2 December 2013-just days after the DQSA was signed into law-FDA said it wanted public input on which drugs should comprise such a list.

"To identify candidates for the difficult-to-compound list, FDA is seeking public input in the form of specific drug products or categories of drug products that are difficult to compound," the agency wrote.

Once it has a list of candidates, FDA will then consult with a newly created Pharmacy Compounding Advisory Committee (PCAC) before issuing a final difficult-to-compound list by regulation.

Nominations should include the name of the drug product, as well as a reason why it belongs on the list. FDA also noted that even some complex products will be allowed to remain on the market if they offer particular benefits to patients.

The list of products will be updated in phases, with future additions taking place in the form of amendments. The public will be able to petition FDA to add additional products to the list, regulators said.

Federal Register Notice