ABSTRACT
Drug delivery systems aim to provide accurate and convenient drug administration, to produce the desired therapeutic response with minimal side effects and to maximize patient compliance. Common routes of drug administration include oral, sublingual, buccal, parenteral, respiratory, nasal, transdermal, rectal, vaginal, ocular, and otic. Targeted drug delivery to the site of action maximizes the pharmacological effect and minimizes side effects relating to unwanted responses at other sites. The oral route is the most commonly used route for systemic drug delivery. It is both convenient and economical. The respiratory route of administration by inhalation is a wellestablished method of administration for various drugs. Drug absorption in the respiratory tract occurs mainly by passive diffusion, by which absorption is determined by molecular size and lipophilicity. Other absorption routes include transport through aqueous pores, carrier-mediated active transport processes, and lymphatic transport. Various aerosol devices are used for respiratory drug administration.
