Owning Both a 503A Pharmacy and a 503B Outsourcing Facility

A single owner running both a 503A compounding pharmacy and a 503B outsourcing facility sits at the intersection of two frameworks that the Food and Drug Administration regulates as two separate operations, each with its own registration, oversight, and facility definition. Section 503A of the Food, Drug, and Cosmetic Act governs pharmacist and physician compounding tied to an identified patient's prescription. Section 503B governs outsourcing facilities registered with FDA that follow current good manufacturing practice and can compound and ship product without a patient-specific prescription. Owning both keeps the two rulebooks separate and raises four questions: whether the two can share an address, how far staff and recordkeeping separation has to go, how product can move between them, and how FDA and the states view common ownership when the 503A side ships compounded product across state lines.

Sharing a Physical Address

FDA's May 2018 guidance, Facility Definition Under Section 503B of the FD&C Act, permits a 503B outsourcing facility to operate at the same street address as a 503A pharmacy, but only under what FDA calls complete segregation. FDA's published indicia of segregation are specific: no shared rooms, no shared fixed compounding equipment or supplies, separate entrances and exits, no shared internal pass-through, and permanent physical barriers between the two. A curtain or a shared workbench does not meet that standard. Section 503B itself defines an outsourcing facility as a facility at one geographic location or address, so the address itself is part of what makes a 503B facility distinct.

Staff, Inventory, Records, and Labeling

FDA's published segregation guidance speaks most directly to physical space, equipment, and labeling: a compounder is responsible for labeling, promoting, and advertising its compounded drug products so customers are not misled about whether an outsourcing facility or a 503A establishment produced them. The guidance does not spell out, with the same specificity, how staffing or inventory records must be kept distinct beyond what segregated space and equipment already require. In practice, personnel and inventory records still need to show unambiguously which batch was compounded under which authority, because a state board inspecting the 503A side and FDA inspecting the 503B side are each entitled to records of only their own framework's activity. Where current guidance does not address a specific arrangement, treat the gap as a question to confirm against FDA's current guidance, and with counsel, before going into operation, not as permission.

Transfers of Product Between the Entities

Moving inventory from the 503B operation to the 503A pharmacy, or compounding on one registration using material meant for the other, draws FDA attention because a product's regulatory status follows the pathway under which it was compounded, not the owner's convenience. Product compounded under 503B's batch, no-prescription authority does not become 503A product because a commonly owned pharmacy later dispenses it. Current guidance does not set out a specific transfer protocol for commonly owned entities, which is reason to document the basis for any transfer in writing rather than assume one registration's paperwork covers both.

Each product in a combined 503A and 503B operation stays governed by whichever section's rules applied the day it was compounded, not by which entity happens to dispense it.

Common Ownership and Interstate Distribution

Section 503A's default rule, absent a signed memorandum of understanding between FDA and the state, caps a 503A pharmacy's out-of-state distribution of compounded drug products at 5% of its total prescription orders dispensed or distributed. The statute lets a pharmacy in a state that signs FDA's standard MOU distribute compounded drugs out of state without that cap, but FDA considers the standard MOU it published in October 2020 suspended after a court remanded it in September 2021, does not expect states that signed it to carry out its terms, and has told the public it does not currently intend to enforce the 5% limit while it completes rulemaking on a replacement. Until that rulemaking is final, neither the 5% limit nor the MOU route is being actively enforced, and how a commonly owned, affiliated 503B facility's interstate shipments would count toward a 503A pharmacy's own distribution under any final rule is unaddressed. Confirm the current enforcement posture on FDA's compounding information page before relying on any specific percentage.

Why Early Legal Counsel Is Critical

It is critical that a pharmacy owner weighing or already operating a combined 503A and 503B structure retain experienced healthcare defense counsel before finalizing the facility layout, staffing, or transfer protocol between the two operations. Early legal involvement can review a segregation plan against FDA's current guidance, confirm how state board rules apply alongside FDA's oversight of the 503B side, and document the ownership structure and distribution calculation before an inspection raises the question first. Delaying that review until a finding is made can leave the facility defending a structure never confirmed against current guidance.

How Health Law Alliance Can Help

Health Law Alliance advises pharmacy owners who operate, or are weighing, a combined 503A and 503B structure on facility segregation, recordkeeping, and the common-ownership questions FDA and state boards raise during inspection, including how cGMP obligations on the 503B side interact with state board oversight on the 503A side. If your pharmacy is structuring or defending a combined operation, contact our compounding pharmacy attorneys for a free, confidential consultation.