Topical route of drug administration refers to the application of medication to the surface of the skin or mucous membrane of the eye, ear, nose, mouth, vagina, etc. with the intent of containing the pharmacological effect of the drug only to the surface or within the layers of skin or mucous membrane. Drugs for topical application are usually available as creams, ointments, gels, lotions, sprays, powders, aerosols, liniments, and drops.
Topical route of administration provides a high local concentration of the drug without affecting the general circulation. However, absorption into the systemic circulation is very common and can lead to adverse effects. Sometimes, this systemic absorption is made use of, for its therapeutic value.
1. Useful for local delivery of agents, particularly those which have toxic effects if administered systemically.
2. Used for most dermatologic and ophthalmologic preparations.
3. Avoidance of first pass metabolism.
4. Convenient to use and easy to apply.
5. The gastro-intestinal incompatibility will be avoided.
6. Avoidance of the risks and inconveniences of administration and the varied conditions of absorption, like pH changes, presence of enzymes, gastric emptying time, etc. in enteral or parenteral routes.
7. Easy termination of medications when needed.
8. Drug delivered selectively to a specific site.
9. Provides drug utilization with short biological half-life and narrow therapeutic window.
10. Better patient compliance.
11. Suitable for self-medication.
12. Avoids fluctuation in drug levels and risks.
13. Provides effectiveness in low doses and by continuous drug input.
14. A large area of application compared to other routes.
15. Improved physiological and pharmacological response.
Read Also: Transdermal Route of Drug Administration
1. Most drugs have a high molecular weight and are poorly lipid-soluble, so are not absorbed via skin or mucous membranes.
2. Possibility of local skin irritation at the site of application.
3. Contact dermatitis due to some drug and/or excipients may occur.
4. Can be used only for those drugs which require low plasma concentration for action
5. Enzymes in the epidermis may denature the drugs.
