In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, nasopharynx, or the eye. Some hydrophobic chemicals such as steroid hormones can be absorbed into the body after being applied to the skin in the form of a cream, gel or lotion. Transdermal patches have become a popular means of administering some drugs for birth control, hormone replacement therapy, and prevention of motion sickness.

References

• Goodman & Gilman's The Pharmacological Basis of Therapeutics