NDCs - Concept, Construction and Compliance

All drug products, whether prescription, over-the-counter, homeopathic or even combination cosmetic-drug products are required to have a National Drug Code number, otherwise known as an NDC.  This number is a unique 10-digit, 3-segment number that identifies the labeler (which could be the manufacturer or the distributor), the product, and the package size. 

The concept of an NDC, what it is and how it’s configured seems to be confusing to many companies who are under the impression that it must be obtained from the FDA. But the process is actually much easier than that once it is understood how the number is constructed.

The FDA assigns only the first part of the NDC, known as the labeler code.  This is a 5-digit number assigned to a firm upon application of a Labeler Code Request which is done through the agency’s electronic submission portal.  A “labeler” is a firm that manufactures, repackages, relabels, or distributes (under its own name) the drug. As such, private label distributors are required to have their own labeler code.  

The NDC is not required to appear on product labeling, but if a firm wishes to include it, the FDA has set forth specific criteria regarding its placement, prominence and display.  These requirements are outlined further in 21 CFR 207.35 (b)(3). 

Once it has its labeler code, the firm itself assigns the last remaining numeric characters of the NDC (the Product Code and Package Code).  As worded in 21 CFR 207.35 (b)(2)(ii):

“The manufacturer or distributor will assign the Product Code and the Package Code before drug listing and include these codes in Drug Product Listing. The manufacturer or distributor may use either of two methods in assigning the Product and Package Codes: a 3-2 Product-Package Code configuration (e.g., 542-12) or a 4-1 Product-Package Code configuration (e.g., 5421-2). A manufacturer or distributor with a given Labeler Code shall use only one such Product-Package Code configuration and shall use this same configuration in assigning the Product-Package Codes for all drugs included in the drug listing.”

While there are products with 4-4-2 NDC configurations, these are associated with companies that were in existence when 4-digit labeler codes were being assigned. The FDA currently assigns 5-digit codes only.

Once the labeler code is obtained, the company assigns the product code and package code as follows:  

The Product Code identifies the product - its strength, dosage form, and formulation. There is no set procedure or pattern but it will be unique to each firm based on their choosing. Different formulations, or different strengths of the same formulation, should have different product codes.  Likewise, products that share the same formulation but have different characteristics (e.g. shape, color) should also have different codes.  

The Package Code identifies the trade package size and type.  Different package codes differentiate between the quantitative and qualitative attributes of the product packaging, like the number of pills a bottle, or the weight or volume of a product, or the type of package like bottle, blister pack or tube.

Whether to use a 3-2 configuration or 4-1 configuration will be dependent on the number and type of products / packaging configurations of a given firm.  Consideration should be given to future growth and expansion so that a maximum number of numeric combinations are possible. In any case, it’s strongly recommended that a firm defines its numbering system in a procedure so that it is consist across the product range.  This also helps to avoid errors and duplication.

The NDC is “registered” with the FDA at the time of drug listing, i.e., when the product enters commercial distribution and subsequently gets published in the agency’s NDC Directory, a searchable database on their website. It the product is discontinued, that NDC cannot be assigned to another product for 5 years after the last expiration date of that product. Note that Drug Listing does not confer any type of FDA approval; but rather serves as a mechanism for the agency to monitor currently marketed drug products.