# A Non-Fungible Token Solution for the Track and Trace of Pharmaceutical Supply Chain
## 3 Track and Trace and Serialization Process of a Pharmaceutical Factory
### Serialization Process  
As previously stated, the prerequisite for the implementation of the serialization process is the adoption of a unique code that allows the quick identification of a package and the product in which it is carried. Three main packaging layers can be identified in the pharmaceutical industry, as shown in Figure 2.  
**Primary Packaging** is the packaging in contact with the drug. The most notable examples of primary packaging is the aluminium blister suitable for hard packing of medical and pharmaceutical products such as pills, capsules, and tablets. Other examples are vials and flacons. The serialization of the primary packaging is not a requirement in any market except for those in which the patient can directly purchase the primary packaging.  
**Secondary Packaging** contains the medicine or medicines inside the primary packaging. A carton box, known also a unit box, is the best example of this packaging. The serialization of this packaging is a must for regulations compliance; for the EU-FMD and other regulations, an additional tamper-evident mechanism is also required to avoid counterfeiting and guarantee that the medicine has not been opened before handed to the patient.  
**Tertiary Packaging** is used to carry out business-to-business operations in the supply chain. Tertiary packaging includes pallets, bundles, and cases. This level of packaging is the most important point to ensure traceability with serialization.  
In serialization, the packaging has to follow a hierarchical aggregation because the marking of each box with a unique identifier allows for dating back from the outer to the inner packaging level and vice versa, assuming that the packaging hierarchy is known and tracked in a computerized database. In fact, unit loads are not assembled randomly but according to the information carried by a work order [77]. To be compliant with the serialization specifications described in the 2011/62/EU Directive, each box of each level must be marked with a unique identifier. The codification of the identifier must respect several rules that depend on the packaging level (e.g., unit box, case box, or unit load) of the product packaged and, more importantly, on the encoding specification of the country in which the product will be traded.  
The structures of the unique code definitions of each country are similar to each other and, in fact, following the GS1 standard, they are printed in the form of a 2D QR code. Because each country adopts slightly different QR code formats, in order to ship and commercialize a drug product, the pharmaceutical companies have to prepare the packaging of the products accordingly. Using the GS1 standard, the basic pieces of information required to create the QR codes are the following:  
Figure 2: Serialization and packaging hierarchy (unit box, case box, and pallet).  
_GTIN_: The global trade item number (GTIN) can be used to identify a product at any packaging level, e.g., consumer unit, inner pack, case, or pallet. This information provides a common language to uniquely identify the item worldwide for all relevant entities and trading partners;
* _Serial number_: A numeric or alphanumeric character sequence consisting of up to 20 digits, which must be unique for each GTIN;
* _Lot information_: A company-specific production that allows identification of the information of the lot produced;
* _Expiration date_: The expiration date of the product.  
The GTIN can be obtained from the company that needs to commercialize a product by registering its global location number (GLN) with the local GS1 organization of the country. The global location number is a 13-digit number used to uniquely identify any legal entity, functional entity, or physical location. This unique identifier is comprised of a GS1 company prefix, location reference, and check digit. The GLN is used to uniquely identify any location or legal entity anywhere in the world. Figure 3 shows two examples of standard QR codes for Europe and the U.S.