Fats and oils oxidation

Hydrolysis, the reaction of fats and oils with water, and oxidation, the chemical reaction in which oxygen combines with another substance with the liberation of heat, are the two basic processes that result in the deterioration of oils and fats. Oxidation is mostly responsible for much more of the deterioration of fats and oils than hydrolysis. 

Caution must be exercised with these kinds of substances and they need to be stored properly and not being used if the expiry date is exceeded. The influence of light should not be underestimated. The Ph. Eur. states for many substances, for example tretinoin, phytomenadione, corticosteroids and benzodiazepines that they must be protected against light. In oils and fats oxidation and peroxide formation is increased by light. Sorbic acid in solution (so also in preparations) is sensitive to light. 

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