Some substances such as elemental carbon and phosphorus exist in more than one crystalline form and are said to be polymorphic. Polymorphs generally have different melting points and solubilities, even though they are chemically identical.
Theobroma oil can exist in four different polymorphic forms of which only one is stable.
This is an important consideration in the preparation of theobroma suppositories. When the liquid formed subsequently cools, the solid is more stable and melts at 34 C. Different polymorphs exhibit different solubilities. This may be useful in case of slightly soluble drugs. Polymorphism can also be a factor in suspension technology. Cortisone acetate has been found to exist in at least five different forms, four of which are unstable in water and change to the stable form.