Description
CVM establishes assay limits for drugs in medicated feeds (i.e., Type B and Type C medicated feeds) as part of the approval process for Type A medicated articles. The term “assay limits” refers to how much the measured amount of drug can deviate from the labeled amount of drug. The assay limits for Type B and Type C medicated feeds are specified as a range and published in 21 CFR §558.4(d). When a medicated feed assay value falls within this range using a validated method accepted by CVM, it indicates that the measured drug level in medicated feed is consistent with the labeled drug level. The assay limits are not intended to permit a feed manufacturer to add more or less than the labeled amount of drug to the medicated feed. Assay limits are used pre-approval to ensure that medicated feeds in Target Animal Safety (TAS), Effectiveness (EFF), Chemistry, Manufacturing, and Controls (CMC), Bioequivalence (BE), and Human Food Safety (HFS) residue chemistry studies contain the appropriate amount of drug, and post-approval for compliance and customer service purposes.
Scope & Applicability
Product Classes
7Final medicated feed intended for consumption; Medicated feed intended for consumption as a complete feed; medicated feed intended for direct consumption by animals; Medicated feed intended for direct consumption by animals
intermediate medicated feed; A medicated feed intended for further manufacture of another medicated feed.; Intermediate medicated feed; Intermediate medicated feed product; medicated feed intended for further mixing; Intermediate medicated feed used to manufacture Type C feed
manufactured using Type A medicated article
For free-choice medicated feeds, CVM suggests using the same PAVs listed in the table.
Assay limits for Type B and Type C medicated feeds are specified as a range.
Assay limits for Type B and Type C medicated feeds are specified as a range.
Specific category of animal drug products
Stakeholders
1Entity responsible for submitting applications under section 524B
Regulatory Context
Attributes
4Calculated as a fraction of Horwitz variability (sigma H).
A %CV for uniformity across the batch of 10 - 15% is considered good.
This guidance recommends a standardized set of PAVs for medicated feeds, based on feed type and drug inclusion rate.
Medicated feed assay limits are based on Permissible Analytical Variability (PAV).
Related CFR Sections (2)
- 21CFR510.455§ 510.455 Requirements for free-choice medicated feeds.
(a) What is free-choice medicated feed? For the purpose of this part, free-choice medicated feed is medicated feed that is placed in feeding or grazing areas and is not intended to be consumed fully at a single feeding or to constitute the entire diet of the animal. Free-choice feeds include, but arRead full regulation →
- 21CFR558.4§ 558.4 Requirement of a medicated feed mill license.
(a) A feed manufacturing facility must possess a medicated feed mill license in order to manufacture a Type B or Type C medicated feed from a Category II, Type A medicated article.Read full regulation →
See Also (3)
- CVM GFI #136 Protocols for the Conduct of Method Transfer Studies for Type C Medicated Feed Assay Methods (Status: Final)
- CVM GFI #292 Chemistry, Manufacturing, and Controls Considerations for Type A Medicated Articles (Status: Draft)
- CVM GFI #120 Veterinary Feed Directive Regulation Questions and Answers (Status: Final)