ABSTRACT
Oils and fats are based on two simple building blocks: glycerol and fatty acids. Dating back to antiquity, fats and oils have played an important role in the composition of cosmetics, providing emolliency and moisturisation, and acting as solvents and vehicles to carry other agents. Oils can be classified by the source from which they are derived such as petrochemical or natural, animal or vegetable. Oils and fats are water-insoluble substances of plant or animal origin that consist predominantly of triglycerides, minor lipids and biologically active ingredients. Crystallization peak time as a function of temperature can then be compared in different oil systems. A routine characterisation of an oil-based formulation covers determination of solid fat content, polymorphic stability, crystallization kinetics and rheology. Differential scanning calorimetry can also be used to measure polymorphism, as melting behaviour may be correlated to crystals present in the oils.
