Abstract
Azithromycin extended release (Zmax, Pfizer Inc) is a novel single-dose administration formulation of azithromycin which won FDA approval in June 2005 and is currently approved for the treatment of community acquired pneumonia and acute bacterial sinusitis. Azitromycin is incorporated into sustained-release microspheres which release the drug slowly through 200 microm pores. Because of this sustained release mechanism, most of the drug is released into the lower gastrointestinal tract, reducing gastrointestinal side-effects, and allowing for a higher dose to be administered. The unique pharmacological properties and extremely long half-life of azithromycin make this drug well suited to single-dose administration but gastrointestinal side effects have previously hampered single-dose therapy.