Provided herein are nanoparticles and methods for using nanoparticles. The nanoparticles include at least three antiretroviral agents. When introduced to cells the nanoparticles cause an increase in the intracellular concentration of the antiretroviral agents to a level that is at least the IC50 against HIV-I or HIV-2. This concentration may be maintained for at least 21 days after the cells are contacted with the nanoparticle. When administered to a subject the nanoparticles cause the concentration of the antiretroviral agents to increase to at least 100 ng/ml in the serum of the subject, at least 0.5 μg/gram tissue in an organ of the subject, or a combination thereof. Such a concentration may be maintained for at least 21 days after the administration.
