Simultaneous therapeutic and diagnostic applications of magnetic PLGA nanoparticles loaded with doxorubicin in rabbit.

In this study, DOX (Doxorubicin) and Fe 3 O 4 magnetic nanocrystals (SPIONs (Superparamagnetic iron oxide nanocrystals)) were encapsulated in the PLGA-PEG: poly(lactide-co-glycolide)-b-poly(ethylene glycol) nanoparticles for theranostic purposes. The final prepared formulation which is called NPs (Nanoparticles) exhibited a particle size with a mean diameter of ~ 209 nm and a sufficient saturation magnetization value of 1.65 emu/g. The NPs showed faster DOX release at pH 5.5 compared to pH 7.4. Also, the cytotoxicity effect of NPs increased compared to Free-DOX alone in C6 glioma cancer cells. For in vivo investigations, the 2.2 Kg rabbits were injected with NPs formulations via a central articular anterior vein in their ears. Furthermore, the images of rabbit organs were depicted via MR (Magnetic resonance) and fluorescent imaging techniques. A negative contrast (dark signal) was observed in T 2 (Relaxation Time) weighted MR images of IV (Intravenously)-injected rabbits with NPs compared to the control ones. The organ's florescent images of NPs-injected rabbits showed a high density of red color related to the accumulation of DOX in liver and kidney organs. These data showed that the NPs have no cytotoxicity effect on the heart. Also, the results of histopathological tests of different organs showed that the groups receiving NPs and Free-DOX were almost similar and no significant difference was seen, except for the cardiac tissue in which the pathological effects of NPs were significantly less than the Free-DOX. Additionally, pharmacokinetic studies were also conducted at the sera and whole bloods of IV-injected rabbits with NPs and Free-DOX. The pharmacokinetic parameters showed that NPs could enhance the DOX retention in the serum compared to the Free-DOX. Altogether, we aimed to produce a powerful delivery nanosystem for its potential in dual therapeutic and diagnostic applications which are called theranostic agents.