Ointments are used topically for several purposes, e.g., as protectants, antiseptics,
emollients, antipruritics, kerotolytics, and astringents. The vehicle or base
of an ointment is of prime importance if the finished product is expected to
function as any one of the above categories. In the case of a protective ointment,
it serves to protect the skin against moisture, air, sun rays and other external
factors. It is necessary that the ointment neither penetrates the human skin
barriers nor facilitates the absorption of substances through this barrier.
An antiseptic ointment is used to destroy or inhibit the growth of bacteria.
Frequently bacterial infections are deeply seated; a base which has the capacity
to either penetrate or dissolve and release the medication effectively is therefore
desired. Ointments used for their emollient effect should be easy to apply,
be non-greasy and effectively penetrate the skin.