Novel 175Yb-Poly (L-Lactic Acid) Microspheres for Transarterial Radioembolization of Unrespectable Hepatocellular Carcinoma.

Novel biodegradable Poly (L-lactic acid) (PLLA) microspheres containing ytterbium were designed for intra-tumoral radiotherapy, especially for radioembolization. 175Yb possess both therapeutic beta and diagnostic gamma radiations. In this work, a process of making ready radiomicrospheres 175Yb (acac)3-loaded PLLA for more consideration has been investigated. The radiomicrospheres were prepared with approximate size of 20-40 µm, and radionuclidic purity > 92%. The radiomicrospheres were stable in-vitro for up to 72 h in normal saline, and also in human serum albumin (HSA). Biodistribution in mice bearing 4T1 tumor showed specific radionuclide uptake over 48 h. Tumor necrosis was also observed at the injection site up to 12 days after injection. These data indicated that 175Yb-PLLA microspheres could be prepared and considered further for radiomicrospheres tumor therapy.

Preparation and evaluation of 188 Re sulfide colloidal nanoparticles loaded biodegradable poly (L-lactic acid) microspheres for radioembolization therapy.

Radioembolization with radioactive microspheres has been an effective method for the treatment of liver lesions. The aim of this study was to prepare carrier-free 188 Re loaded poly (L-lactic acid) (PLLA) microspheres through 188 Re sulfide colloidal nanoparticles (188 Re-SC nanoparticles). The formation of 188 Re-SC nanoparticles was confirmed by ultraviolet-visible spectrophotometry. The labeling yield of 188 Re-SC nanoparticles was verified using the RTLC method. Effects of synthesis parameters on morphology and size of prepared 188 Re-sulfide colloidal-PLLA microspheres (188 Re-SC-PLLA microspheres) were studied by scanning electron microscopy. In vitro stability of 188 Re-SC-PLLA microspheres was investigated in normal saline at room temperature and in human serum at 37°C. In vivo distribution studies and gamma camera imaging were performed in healthy BALB/c mice. The microspheres could be prepared with sizes between 13 and 48 µm (modal value 29 µm) and radiolabeling efficiency >99%. After incubation, the microspheres were found stable in vitro up to 72 hours. The biodistribution after intravenous injection in healthy BALB/c mice showed high accumulation in lung as a first capture pathway organ for microsphere followed by great retention over 48 hours for these microspheres. These data show that 188 Re-SC-PLLA microspheres are suitable candidate for clinical studies.