Use of Blockchain Technology in the Pharmaceutical Industry to Track Medicines in Zambia

Abstract

In Zambia, we do not have a foolproof system that can help in tracking drugs from the manufacturers through the supply chain to the consumers in real time. This paper highlights how we solved this problem through the use of blockchain technology. Blockchain technology provides a distributed record of transactions (ledger) that allows transactions to be written efficiently and permanently. Further, it provides a mechanism for verifying such transactions. The developed solution, the Medicine Tracking System (MTS), uses a public blockchain architecture that works on a Proof of Work (PoW) consensus algorithm. The MTS keeps a record of all the major transactions that occur between the manufacturer and the end-user of the medicine. A transaction can be a sale, a receipt of medicine, a delivery, an issuance of a prescription or even a report of damage. Each transaction is input into the system by the main player or actor at each occurrence of the transaction, keeping note of the details such as the date and location of the transaction. By tracking these details about a transaction, it was possible to trace with certainty and accuracy the path that a particular medicine traversed to the end-user and all the actors involved along the way. Therefore, any unauthorised actors were easily identified and dealt with. Further, the quality of the medicine was monitored and kept in check. Because each transaction is time-sensitive, the duration of medicines in transit or storage was measured concerning their expiry date. The PoW consensus algorithm was used to achieve agreement or consensus on every transaction sent to the network. Multiple nodes participated in validating a transaction, and these had to reach consensus by following the mechanisms provided for by this algorithm. This was achieved by creating a unique timestamp for each transaction and then packaging it into a block. The contents of the block were then hashed using PoW and added to the chain with a pointer to the preceding block's hash through a process called mining. To successfully mine a block, a miner has to compute the solution to a mathematical problem. The mined block then has to be broadcast to the network. This created a record of transactions that could not be altered unless the PoW was redone. The results of the system show that users in the pharmaceutical chain can record transactions they are involved in. Furthermore, the system can transmit all transactions to the blockchain, where miners can capture them, verify them, and add them to the blockchain database, forming an indelible record of transactions. Unlike existing blockchain-based pharmaceutical systems such as MediLedger, PharmaLedger, and Blockpharma, which primarily focus on regulatory integration within high-income countries, our MTS is specifically designed for the Zambian pharmaceutical ecosystem, which lacks the necessary infrastructure and connectivity to adopt existing global models. The novelty of MTS lies in its context-aware implementation, which combines blockchain transparency with localised mobile interfaces, lightweight nodes, and integration with the Zambia Medicines Regulatory Authority framework. This localised adaptation demonstrates how blockchain can be operationalised in low-resource and semi-decentralised environments, providing a scalable, verifiable, and regulatory-compliant model for medicine traceability in developing countries.