Implantable Polyurethane Scaffolds Loading with PEG-Paclitaxel Conjugates for the Treatment of Glioblastoma Multiforme

Improvement of the treatment for Glioblastoma multiforme(GBM)especially the development of in situ controllable drug release is still a major concern.In this study,we developed waterborne biodegradable polyurethane(WBPU)scaffolds incorporated with redox-sensitive and RGD-decorated paclitaxel(PTX)polymer-drug conjugates(PDCs)for targeted GBM therapy in situ.The drug scaffolds could be implanted at residual GBM site post-operation.Dual-targeting PTX-PDCs were obtained through step-by-step conjugation of disulfide linked PTX,poly(ethylene glycol)(PEG),and arginine-glycine-aspartic acid(RGD).The RGD-modified PTX-PDCs were spherical nanoparticles(NPs)that would be released from scaffolds and identified GBM cells actively.Internalized redox-sensitive PTX-PDCs would be decomposed and release PTX inside GBM cells under the circumstances of glutathione(GSH).The release profiles of PTX from the scaffolds with/without GSH were investigated.In vitro cytotoxicity assay revealed that the dual-targeting PTX-PDCs from scaffolds could specifically kill GBM cells and protect normal cells,suggesting that dual-targeting PTX-PDC-loaded scaffolds may have the potential to repair tumor-induced brain injury.In vivo anti-recurrence assay indicated that the PTX-PDC-scaffolds could deliver PTX-PDCs to the GBM cells followed by inhibiting tumor growth and inducing apoptosis.In general,the PTX prodrug-loaded devices exhibited significant anti-GBM effects and normal tissue protection simultaneously,indicating that the WBPU scaffolds incorporated with dual-targeting PTX-PDCs may be a promising strategy for local therapy of GBM.

A multiple-dose pharmacokinetics of polyethylene glycol recombinant human interleukin-6 (PEG-rhIL-6) in rats

Radiation therapy has been widely applied in cancer treatment.However,it often causes thrombocytopenia (deficiency of white blood cells) as an adverse effect.Recombinant human interleukin-6 (rhIL-6) has been found to be a very effective way against this thrombocytopenia,but IL-6 has low stability in blood,which reduces its efficacy.To increases the stability and half-life of rhIL-6,it was modified by polyethylene glycol (PEG).The pharmacokinetics and the tissue distribution of PEG-rhIL-6 labeled with 125I were examined after subcutaneous injection in rats.The pharmacokinetic pattern of PEG-rhIL-6 was defined with linear-kinetics,and we fitted a one-compartment model with half-lives of 10.44–11.37 h (absorption,t1/2Ka) and 19.77–21.53 h (elimination,t1/2Ke),and peak concentrations at 20.51–21.96 h (tpeak) in rats.Half-lives and tpeak of PEG-rhIL-6 were longer than those of rhIL-6 previously reported.In the present study,for deposition of PEG-rhIL-6 in rats,the tissue distribution examination showed that blood was the major organ involved,rather than liver.However,as to the elimination of PEG-rhIL-6,the major organ was the kidney.The excretion fraction of the injection dose recovered from urine was 23.32% at 192 h after subcutaneous administration.Less than 6% of PEG-rhIL-6 was eliminated via the feces at 192 h.These results indicate that PEG-rhIL-6 is a good candidate drug formulation for patients with cancer.

Effect of Trastuzumab on the Micellization Properties, Endocytic Pathways and Antitumor Activities of Polyurethane-based Drug Delivery System

Polyurethane micelles（PM）-based nanovehicles have shown great potential in targeted delivery of therapeutics and diagnostics into tumors.However,the pathways of PMs entering cancer cells and the action mechanism of targeting ligands have yet to be understood.In this contribution,the actively-targeted PM were developed using trastuzumab as a model targeting group.It was found that PM were mainly taken up by SKOV-3 tumor cells via a micropinocytosis process,while the incorporation of trastuzumab to PM enabled a receptor-mediated endocytosis of nanocarriers in cancer cells,leading to more efficient cell entry and enhanced anticancer efficacy of chemotherapeutic drugs both in vitro and in vivo.This study is advantageous to the understanding of the action mechanism of trastuzumab,and significant for the construction of improved formulations for targeted delivery and precise therapy.