Nanoparticle delivery systems for HIV pre-exposure prophylaxis (PrEP): advances and challenges.

HIV pre-exposure prophylaxis (PrEP) encompasses antiviral drugs or formulations that aim to prevent the establishment of a permanent infection if exposure occurs. Conventional oral PrEP approaches require a daily drug regimen for effective prophylaxis, which can become burdensome, and pill fatigue creates challenges for adherence. There is, consequently, interest in the development of long-acting formulations of antiretrovirals that provide protection over extended periods of time after a single treatment. Nanoformulations and nanoparticle delivery strategies play an important role in achieving long acting (LA)-PrEP. This manuscript reviews emerging nanoparticle delivery platforms for LA-PrEP with a particular focus on four distinct classes of nanomaterials, namely, polymeric nanoparticles, lipid-based nanoparticles, inorganic nanoparticles, and hybrid nanoparticles. Nanoparticle design considerations and targeting strategies for the individual classes are examined, and the opportunities and challenges for the different nanomaterials approaches in the context of LA-PrEP are discussed.