Other routes of drug applicaton

Pulmonic absorption is very fast - just like the exchange of oxygen and carbon dioxide. An adult s lung has a full 80 m of exchange-active area. 

Once the drug has entered the systemic circulation, it needs to reach its target site. Target sites may be located in various compartments  

Within the blood vessels. Example blood coagulation / clot dissolution. No problems of distribution here, drug molecules of any size and shape can be used (when intravenously applied). 

In the organ tissue, outside the blood vessels, but extracellular or superficially exposed on the cell surface. Example Most receptors for hormones and transmitters. 

In the organ tissue, intracellularly located. Example Many enzyme inhibitors. 

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