Antioxidants are applied in pharmaceutical formulations in order to protect the formulation against the oxidative process. They are substances capable of delaying or inhibiting the oxidation of other molecules. The antioxidants mechanism of action can be divided into three forms:

Interrupting the formation of free radicals: BHA, BHT, α - tocopherol

Promoting the reduction of oxidized components: Ascorbic acid, Sodium metabisulphite

Avoiding oxidation: EDTA, Citric acid