Magnetic nanoparticles (NP) of iron oxides and their composites with hydroxyapatite (HA) are used for the targeted delivery of biologically active compounds (BAS) and drugs and have a significant advantage over traditional methods of therapy, since the active substances immobilized on the nanocarrier are protected from chemical, enzymatic and immune degradation on the way to the target of therapy. A simple one-step method for the synthesis of magnetic nanocarriers of bioactive compounds (BAC) — new amides and benzohydrazides of the 2-arylaminopyrimidine series, containing fragments of the structure of known antitumor drugs, as well as functional NH2 groups providing chemosorption of BAC nanoparticles, was developed. A distinctive feature of the preparation of composites is the presence of 2-arylaminopyrimidine derivatives in the nanocarrier forming medium, including nanosized hydroxyapatite and magnetite - (HAP)FexOy or ((HAP)FexOy)PAD (PAD - polyaldehydedextran) in the covalent immobilization method. The composition, morphology and magnetic characteristics of synthesized nanocomposites were studied. Composites ((HAP) FexOy) BAS with an adsorbed biologically active substance based on 2-arylaminopyrimidinamide derivatives are bioactive nanosystems ready for in vivo applications, for example, for the treatment of bone diseases. To check the effectiveness of a such system using, the kinetics of the BAC release was studied in the work, on the basis of which it was shown that the biologically active compound is released in two stages within 5 hours: 80% of the active substance is released in the first 2 hours, and then the remainder is released in the next 3 hours substances.