There are many routes by which the drugs can be delivered into the body. These routes include oral (drugs taken by mouth), injections, nasal (sprayed into nose), inhalation (breathed into the lungs), rectal (injection into the rectum), cutaneous (applied on the skin), and transdermal (delivery through the skin). Injections can be further divided into intravenous (injection into a vein), intramuscular (injection into a muscle), intrathecal (injection into the space around the spinal cord), and subcutaneous (injection beneath the skin). Each drug delivery route has specific advantages and disadvantages, and the route greatly impacts the therapeutic efficacy of the delivered drug inside the body. The oral route is the most common way to deliver drugs into the body. However, it should be noted that the popularity of oral drug administration is not because it is effective, but because it is convenient. Compared to the majority of the other methods, oral drug administration is the simples...
e-Pharmatimes- "Protecting Ideas, Advancing Healthcare: A Pharma Blog"