The set of legally enforceable rules that govern the market for a drug, involving application of different controls depending on drug risks and needs of local environments. Includes regulation of production (licensed producers), products (price, potency and packaging), availability (licensed vendors, location of outlets, age controls) and marketing (advertising and branding). Legal definition: Regulation describes the way in which government authorities intervene in the market to control a particular legal or legalised drug product (its price, potency, packaging etc.), as well the various aspects of its production, transit, availability, marketing and use. There is no single regulation model – there are a range of regulatory tools that can be deployed in a variety of ways depending on the product and location.