Oxidative Damage Induced by Phototoxic Pheophorbide a 17-Diethylene Glycol Ester Encapsulated in PLGA Nanoparticles

Pheophorbide a 17-diethylene glycol ester (XL-8), is a promising high-active derivative of known photosensitizer chlorin e6 used in photodynamic therapy. However, high lipophilicity and poor tumor accumulation limit XL-8 therapeutic application. We developed a novel XL-8 loaded with poly(D,L-lactide-co-glycolide) nanoparticles using the single emulsion-solvent evaporation method. The nanoparticles possessed high XL-8 loading content (4.6%) and encapsulation efficiency (87.7%) and a small size (182 ± 19 nm), and negative surface charge (−22.2 ± 3.8 mV) contributed to a specific intracellular accumulation. Sustained biphasic XL-8 release from nanoparticles enhanced the photosensitizer photostability upon irradiation that could potentially reduce the quantity of the drug applied. Additionally, the encapsulation of XL-8 in the polymer matrix preserved phototoxic activity of the payload. The nanoparticles displayed enhanced cellular internalization. Flow cytometry and confocal laser-scanning microscopy studies revealed rapid XL-8 loaded nanoparticles distribution throughout the cell and initiation of DNA damage, glutathione depletion, and lipid peroxidation via reactive oxygen species formation. The novel nanoformulated XL-8 simultaneously revealed a significant phototoxicity accompanied with enhanced photostability, in contrast with traditional photosensitizers, and demonstrated a great potential for further in vivo studies.

Preparation of Fe3O4@SiO2–ZnO catalyst and its catalytic synthesis of rosin glycol ester

In order to solve the problems of low recovery, low availability, and high cost in the synthesis of rosin glycol ester, a series of supported ZnO magnetic catalysts were prepared with Fe3O4 as the magnetic center, and their structures and compositions were characterized by TEM, XRD, and XPS. Through screening, the results show that Fe3O4@SiO2–ZnO has the best catalytic effect, far better than other catalysts, and has good stability. At the same time, the effects of zinc source and its load and different reaction conditions on the synthesis of rosin glycol ester were also investigated. The results showed that: When zinc chloride was used as zinc source, theoretical loading of zinc source was 0.45 g, reaction temperature was 270°C, reaction time was 5 h, and catalyst dosage was 0.2 g, the esterification rate of rosin-glyceryl ester was 87.2% and acid value was 26.5 mg KOH g−1.