The worldwide spread of AIDS (acquired immunodeficiency
syndrome), an epidemic disease in continuous development, has
required and still requires potent antiretroviral chemotherapeutic
agents for reducing the number of deaths caused by HIV-1
(human immunodeficiency virus type 1), the etiological agent of
AIDS. Global estimates of WHO/UNAIDS showed 33.4 million
people infected with HIV/AIDS at the end of 2008, with 2.7
million newly infected and 2.0 million deaths.