Studies On The Preparation And Properties Of Magnetic Targeted Drug Nanoparticles

Photodynamic therapy (PDT) is an innovative treatment method for various diseases, such as cancers, age-related macular degeneration (AMD), actinic keratosis, rheumatoid arthritis and so on. PDT is based on the concept that a photosensitizer (PS) excited by laser can transfer its energy to molecular oxygen to produce reactive oxygen species (ROSs), such as singlet oxygen (¹O₂) or free radical that can cause an irreversible oxidizing damage to surrounding tissues. The defect of PDT is photosensitizer has skin phototoxic reaction to patient who has to stay in dark room for about one month, so the clinical application is restricted. In recent years, magnetic nanoparticles (MNP) offer exciting new opportunities toward developing effective drug guiding delivery systems, as it is easily transferred to the target site by an external localized magnetic field gradient. In this paper, PDT was combined with magnetic nanoparticles to enhance the targeting ability of drugs and lower skin phototoxic reaction which will be helpful for the extensive application of PDT in clinics.Three PDT drug magnetic nanocarriers were synthesized. Firstly, superparamagnetism Fe₃O₄ nanoparticles were prepared by the titration hydrolyzation method, and then modified by oleic acid. Secondly, the Fe₃O₄ nanoparticles was used to absorb the PDT drug 2, 7, 12, 18-tetramethyl-3, 8-di-( 1 -propoxyethyl)-13, 17-bis-(3-hydroxypropyl) porphyrin (PHPP), and magnetic chitosan composite nanoparticles were prepared by an electrostatic self-assembly technique. Thirdly, Fe₃(VOA compound was used to adsorb PHPP. Magnetic silica nanocarriers were synthesized by microemulsion method combined with sol-gel method, and magnetic PLA nanocarriers were synthesized by Solvent Evaporation Method. The nanocarriers prepared were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible (UV-vis) absorption spectra and Fluorescence intensity to detect their crystal structure, modality, size, drug contents and fluorescence capability, respectively. The three nanocarriers were approximately spherical, (PHPP-Fe₃O₄/OA)/SiO₂ had the size in 16.4±3.9 nm, (PHPP-Fe₃O₄)/CS 20.6±5.1 nm , and (PHPP-Fe₃O₄/OA)/PLA 30-50 nm. Fe₃O₄ nanoparticles were spinel, while SiO₂ and PLA were amorphous corresponding to the XRD spectrum. The FT-IR spectrum and the fluorescence excitation peak indicated that the drug existed in the nanocarriers. The drug encapsulation efficiency of (PHPP-Fe₃O₄/OA)/SiO₂ was 20.8%, and (PHPP-Fe₃O₄)/CS's was 87.5%. The drug loading of (PHPP-Fe₃O₄/OA)/PLA was 27.98%. It was proved that (PHPP-Fe₃O₄/OA)/SiO₂ has distinctive Photodynamic effect to tumor cell Hela. The Photodynamic activity of (PHPP-Fe₃O₄)/CS and (PHPP-Fe₃O₄/OA)/PLA to tumor cell Hela are being carried out.The magnetic SiO₂ nanoparticles loaded with naproxen were synthesized by acidifying technology. The reaction condition was study fully. The nanocarriers were characterized by XRD, TEM and UV-vis absorption spectra to detect their crystal structure, modality, size, and drug contents. The synthesized nanoparticles were size in 10～20 nm. The drug encapsulation efficiency is～31.4% and the drug loading is 7.6%. The initial rapid release is about 40% within 4 h. In succession, it is a slower release phase as the entrapped drug slowly diffuses out, the slower release period is about 30 h until 80%.