The goal of this study was to investigate the solution behavior of nanosystems composed of self-assembling amphiphilic diblock copolymers, poly(ethylene oxide-b-phenyl oxazoline) and poly(isoprene-b-ethylene oxide) (PEO-b-PPhOx and PI-b-PEO), with encapsulated iron oxide nanoparticles (γ-Fe₂O₃). The hybrid nanosystems were tested in aqueous solution, under physiological conditions and in mixtures with serum proteins. Light scattering methods were used to probe changes in size and mass of the formed aggregates in different solution conditions and as a function of storage time. The developed stable hybrid systems with encapsulated magnetic nanoparticles were able to entrap the anti-inflammatory drug, indomethacin. This work demonstrates versatile nanosystems with metal oxide characteristics for bio-imaging and the potential for drug delivery in aqueous media.