Background: Superparamagnetic iron oxide nanoparticles are attractive materials that have been widely used in medicine for drug delivery, diagnostic imaging, and therapeutic applications. In our study, superparamagnetic iron oxide nanoparticles and the anticancer drug, doxorubicin hydrochloride, were encapsulated into poly (D, L-lactic-co-glycolic acid) poly (ethylene glycol) (PLGA-PEG) nanoparticles for local treatment. The magnetic properties conferred by superparamagnetic iron oxide nanoparticles could help to maintain the nanoparticles in the joint with an external magnet.
Methods: A series of PLGA:PEG triblock copolymers were synthesized by ring-opening polymerization of D, L-lactide and glycolide with different molecular weights of polyethylene glycol (PEG(2000), PEG(3000), and PEG(4000)) as an initiator. The bulk properties of these copolymers were characterized using (1)H nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared spectroscopy, and differential scanning calorimetry. In addition, the resulting particles were characterized by x-ray powder diffraction, scanning electron microscopy, and vibrating sample magnetometry.
Results: The doxorubicin encapsulation amount was reduced for PLGA:PEG(2000) and PLGA:PEG(3000) triblock copolymers, but increased to a great extent for PLGA:PEG(4000) triblock copolymer. This is due to the increased water uptake capacity of the blended triblock copolymer, which encapsulated more doxorubicin molecules into a swollen copolymer matrix. The drug encapsulation efficiency achieved for Fe(3)O(4) magnetic nanoparticles modified with PLGA:PEG(2000), PLGA:PEG(3000), and PLGA:PEG(4000) copolymers was 69.5%, 73%, and 78%, respectively, and the release kinetics were controlled. The in vitro cytotoxicity test showed that the Fe(3)O(4)-PLGA:PEG(4000) magnetic nanoparticles had no cytotoxicity and were biocompatible.
Conclusion: There is potential for use of these nanoparticles for biomedical application. Future work includes in vivo investigation of the targeting capability and effectiveness of these nanoparticles in the treatment of lung cancer.
Keywords: doxorubicin encapsulation; drug encapsulation efficiency; superparamagnetic iron oxide nanoparticles; triblock copolymer; water uptake.