What is Good Distribution Practice (GDP)?

Good Distribution Practice (GDP) is the set of rules that keeps a medicine's quality intact while it is stored and transported after leaving the manufacturer. It covers the warehouse, transport, documentation and recall arrangements together.

When a medicine leaves the production line, its quality is documented: it has been tested and the batch has been released. From then on the product passes through warehouses, vehicles, wholesalers and pharmacies. Good Distribution Practice (GDP) is the set of rules that keeps its quality unchanged along that journey. The same rules also make it harder for falsified medicines to enter the supply chain.

How is GDP different from GMP?

Good Manufacturing Practice (GMP) governs how a product is made and how a batch is released. GDP starts where release ends: where the product is stored and under which conditions, how it is transported and to whom it is delivered. Both have the same aim. The patient should receive the quality that was tested at the factory.

What does GDP cover?

The EU GDP guidelines published in 2013 (2013/C 343/01) have ten chapters:

Quality management
Personnel
Premises and equipment
Documentation
Operations
Complaints, returns, suspected falsified medicinal products and recalls
Outsourced activities
Self-inspections
Transportation
Specific provisions for brokers

The World Health Organization’s counterpart is its guidance on good storage and distribution practices for medical products (WHO TRS No. 1025, Annex 7). Both texts answer the same question: whoever holds the product, it must stay within its label conditions and remain traceable.

What does it ask for in practice?

The expectations can sound abstract, but each has a concrete meaning in a warehouse. A few examples:

A wholesale distributor runs a quality system and names a responsible person for it.
The temperature profile of a storage area is mapped before the area is used. Permanent monitoring devices are then placed according to that map.
Monitoring equipment is calibrated at defined intervals, and an alarm goes off when conditions leave their range.
Stock rotates so that the product with the nearest expiry date leaves first (FEFO), and exceptions are recorded.
Each deviation is written down and investigated, then kept with its outcome.
The recall arrangements are checked for effectiveness regularly, at least once a year.

Why does the warehouse matter so much?

The warehouse is usually where a product spends the longest time in the distribution chain. A rack, a loading dock or a cold room door are all places where the product can leave the condition on its label. That is why most of what GDP asks of a warehouse is about measuring the condition, recording it and knowing what to do when it slips. We explain how temperature mapping works in a separate article.

The second big theme is traceability. If nobody knows which batch sits on which shelf and where it was shipped, a product cannot be brought back when something goes wrong. That is why FEFO and batch traceability and recall readiness sit at the centre of GDP.

The situation in Türkiye

In Türkiye the authority for medicines and medical devices is the Turkish Medicines and Medical Devices Agency (TİTCK). Pharmaceutical warehouses operate under the rules it sets. For any individual product, the storage condition that applies is always the one on its approved label.

In short

GDP is less a document than a way of working. The quickest way to see whether a warehouse works that way is to ask three questions: how are conditions measured, who holds the records, and who is the first to know when something goes wrong?