© 2021 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.Poly(ethylene-alt-maleic anhydride) copolymers are used in various applications as emulsion stabilizers, detergent compositions, viscosity modifiers and drug delivery systems. This work aimed at determining the stability and activity of poly(ethylene-alt-maleic anhydride) copolymer (PEAMA) as drug carrier candidate at different pHs and in various artificial body fluid media such as 5% dextrose solution, PBS solution and 0.9% isotonic NaCl solution. To determine the stability of PEAMA, the polydispersity, particle size, mobility and zeta potential of PEAMA were measured at different pH values and in various artificial body fluid media via zetasizer. The activity of PEAMA was investigated at different pH values and in various artificial body fluid media based on the time effect by UV/VIS measurements. According to the obtained results, the optimum conditions of stability and activity of PEAMA copolymer were determined.