The use of anti-retroviral agents (ART), namely highly active anti-retroviral therapy (HAART) has significantly diminished the mortality associated with human immunodeficiency virus type-1 (HIV-1) disease. However, treatment failures, dosing complexities, and adverse effects all limit the long-term therapy in infected peoples. Mononuclear phagocytes serve as not only as early reservoirs but also vehicles for dissemination for HIV-1. Based on previous work with indinavir nanoparticles (NP) we want to extend our work to include combination ARV agents and fabricate NP with combinations of drugs. Nanoformulations can support sustained drug release to HIV-1 tissues considered sanctuaries and deliver drug concentrations that far exceed the inhibitory quotient. We hypothesize that combination ARV nanoformulated drug delivery system can be optimized to eradicate HIV-1 from restricted areas of the body. Using a biodegradable polymer (poly (DL-lactide-co 5-caprolactone)), combined ARV agents (ritonavir RTV, lopinavir LPV, and efavirenz EFV) will be entrapped into a nanoparticle and efficiency will be investigated. Liquid chromatography, scanning electron and confocal microscopy, and functional studies in macrophages as a drug delivery system will be gathered. A hollow fiber in vitro model will explore the pharmacodynamics of HIV- 1 inhibition as measured by p24 antigen assay and ART NP drug levels measured by liquid chromatography. Penetration into macrophages will be assessed by liquid chromatography and confocal and transmission electron microscopy. The nanoformulations will be used as a drug delivery system to improve tissue penetrance of ART into the reticuloendothelial system (RES;spleen, liver, lymph nodes) in mice. The pharmacodynamics and pharmacokinetics of combination ARV NP will be determined using in vitro and in vivo systems over extended time periods as compared to free soluble drugs as well as blank nanoparticles. The aims of this proposal are a better understanding of how to optimize the use of NP drug delivery technology to inhibit the production of virus from restricted areas of the body where HIV-1 hides. These approaches offer direct patient benefit for the treatment of HIV-1. PUBLIC HELATH RELEVANCE: This application will investigate the pharmacology of combination antiretrovirals (ritonavir, lopinavir, and efavirenz) fabricated into nanoparticles both in cell culture systems and in animals. The nanoparticles will be delivered to HIV-1 sanctuaries (spleen, liver, lymph nodes). Due to the nanoparticle small size, the particles will stay in tissue longer and allow for less frequent dosing. This nanoparticle delivery system could affect the future of HIV- 1 treatment.