According to the European Medicines Agency Good distribution practice (GDP) ensures that the level of quality determined by GMP is maintained throughout the distribution network, so that authorised medicines are distributed to retail pharmacists and others selling medicines general public without any alteration of their properties.
The principles of GDP are stated in Directive 92/25/EEC.
For more information, see the guidelines on GDP of medicinal products for human use.
(Source: European Medicines Agency)