PEGylated synthetic surfactant vesicles (Niosomes): novel carriers for oligonucleotides

Gum arabic-coated magnetic nanoparticles for potential application in simultaneous magnetic targeting and tumor imaging

Magnetic iron oxide nanoparticles (MNP) coated with gum arabic (GA), a biocompatible phytochemical glycoprotein widely used in the food industry, were successfully synthesized and characterized. GA-coated MNP (GA-MNP) displayed a narrow hydrodynamic particle size distribution averaging about 100 nm; a GA content of 15.6% by dry weight; a saturation magnetization of 93.1 emu/g Fe; and a superparamagnetic behavior essential for most magnetic-mediated applications. The GA coating offers two major benefits: it both enhances colloidal stability and provides reactive functional groups suitable for coupling of bioactive compounds. In vitro results showed that GA-MNP possessed a superior stability upon storage in aqueous media when compared to commercial MNP products currently used in magnetic resonance imaging (MRI). In addition, significant cellular uptake of GA-MNP was evaluated in 9L glioma cells by electron spin resonance (ESR) spectroscopy, fluorescence microscopy, and MRI analyses. Based on these findings, it was hypothesized that GA-MNP might be utilized as a MRI-visible drug carrier in achieving both magnetic tumor targeting and intracellular drug delivery. Indeed, preliminary in vivo investigations validate this clinical potential. MRI visually confirmed the accumulation of GA-MNP at the tumor site following intravenous administration to rats harboring 9L glioma tumors under the application of an external magnetic field. ESR spectroscopy quantitatively revealed a 12-fold increase in GA-MNP accumulation in excised tumors when compared to contralateral normal brain. Overall, the results presented show promise that GA-MNP could potentially be employed to achieve simultaneous tumor imaging and targeted intra-tumoral drug delivery.

Novel PEG-coated niosomes based on bola-surfactant as drug carriers for 5-fluorouracil

Innovative niosomes made up of α,ω-hexadecyl-bis-(1-aza-18-crown-6) (bola), Span 80® and cholesterol (2:5:2 molar ratio) are proposed as suitable delivery systems for the administration of 5-fluorouracil (5-FU), an antitumoral compound largely used in the treatment of breast cancer. The bola-niosomes, after sonication procedure, showed mean sizes of ~200 nm and a loading capacity of ~40% with respect to the amount of 5-FU added during the preparation. Similar findings were achieved with PEG-coated bola-niosomes (bola, Span 80(R), cholesterol, DSPE-mPEG2000, 2:5:2:0.1 molar ratio respectively). 5-FU-loaded PEG-coated and uncoated bola-niosomes were tested on MCF-7 and T47D cells. Both bola-niosome formulations provided an increase in the cytotoxic effect with respect to the free drug. Confocal laser scanning microscopy studies were carried out to evaluate both the extent and the time-dependent bola-niosome-cell interaction. In vivo experiments on MCF-7 xenograft tumor SCID mice models showed a more effective antitumoral activity of the PEGylated niosomal 5-FU at a concentration ten times lower (8 mg/kg) than that of the free solution of the drug (80 mg/kg) after a treatment of 30 days.

Efficient tumor targeting of hydroxycamptothecin loaded PEGylated niosomes modified with transferrin

The aim of the present report was to exploit the possibility of combination of the stealth action by polyethylene glycol cyanoacrylate-co-hexadecyl cyanoacrylate (PEG-PHDCA) modified niosomes and active targeting function of transferrin (Tf) by transferrin receptor-mediated endocytosis to promote drug delivery to solid tumor following intravenous administration with hydroxycamptothecin (HCPT) as model drug. HCPT-loaded PEG-niosomes (PEG-NS) were prepared by thin-film hydration and ultrasound method; the periodate-oxidated Tf was coupled to terminal amino group of PEG to produce the active targeting vesicles with average diameters of 116 nm. The uptake of Tf-PEG-NS into KB cells was concentration and time dependent, which could be inhibited by low temperature and free Tf, indicating that the endocytosis process was energy-driven and receptor specific. Compared with HCPT injection, non-stealth niosomes and PEG-NS, Tf-PEG-NS demonstrated the strongest cytotoxicity to three carcinomatous cell lines (KB, K562 and S180 cells), the greatest intracellular uptake especially in nuclei, the highest tumor concentration and largest area under the intratumoral hydroxycamptothecin concentration curve, as well as the most powerful anti-tumor activity with the inhibition rate of 71% against S180 tumor in mice. The results showed that the transferrin modified PEGylated niosomes could be one of the promising solutions to the delivery of anti-tumor drugs to tumor.