This questions and answers (Q&A) guidance provides FDA’s current thinking on quality-related scientific and regulatory topics that appear frequently in controlled correspondence submissions. The contents of this document do not have the force and effect of law and are not meant to bind the public in any way, unless specifically incorporated into a contract.

This document is intended only to provide clarity to the public regarding existing requirements under the law. FDA guidance documents, including this guidance, should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in Agency guidance means that something is suggested or recommended, but not required.