Lamivudine (LAM), known as 3TC, is an antiviral drug in the class of nucleoside analogue reverse transcriptase inhibitors (NRTIs). LAM is widely used for treatment of human immunodeficiency virus (HIV) and proven effective against hepatitis B virus (HBV). It is commercially available in tablet and oral solution dosage forms and used both in children and adult patients. Even though oral bioavailability is high as 60-80%, the problem with treatment is that it requires frequent admin- istration due to its short half-life of 4 to 6 hours. Considering that chronic use with constant exposure causes accumulation and dose dependent side effects, it is necessary to develop new systems to improve therapy with LAM [1]. Modified release kinetics can be achieved by nanoparticles (NPs) prepared with various materials including polymers. One of the most com- mon polymer groups used is Eudragit; which has many variations that can be used alone or in combinations. Eudragit RS 100 (ERS) is a copolymer of poly (ethylacrylate, methyl-methacrylate and chlorotrimethyl-ammonioethylmethacrylate) con- taining quaternary ammonium groups [2].

In this study, LAM loaded NPs are prepared by nano spray drying method and their in vitro characteristic properties are evaluated.