Xiaoling Fang

Angiopep-conjugated poly(ethylene glycol)-co-poly(ε-caprolactone) nanoparticles as dual-targeting drug delivery system for brain glioma.

Dual-targeting nanoparticle drug delivery system was developed by conjugating Angiopep with PEG-PCL nanoparticles (ANG-NP) through bifunctional PEG to overcome the limitations of low transport of chemotherapeutics across the Blood-brain barrier (BBB) and poor penetration into tumor tissue. ANG-NP can target the low-density lipoprotein receptor-related protein (LRP) which is over-expressed on the BBB and glioma cells. Compared with non-targeting nanoparticles, a significantly higher amount of rhodamine isothiocyanate-labeled dual-targeting nanoparticles were endocytosed by U87 MG cells. The antiproliferative and cell apoptosis assay of paclitaxel-loaded ANG-NP (ANG-NP-PTX) demonstrated that ANG-NP-PTX resulted in enhanced inhibitory effects to U87 MG glioma cells. The transport ratios across the BBB model in vitro were significantly increased and the cell viability of U87 MG glioma cells after crossing the BBB was obviously decreased by ANG-NP-PTX. Enhanced accumulation of ANG-NP in the glioma bed and infiltrating margin of intracranial U87 MG glioma tumor-bearing in vivo model were observed by real time fluorescence image. In conclusion, Angiopep-conjugated PEG-PCL nanoparticles were prospective in dual-targeting drug delivery system for targeting therapy of brain glioma.

Multifunctional Pluronic P123/F127 mixed polymeric micelles loaded with paclitaxel for the treatment of multidrug resistant tumors

The aim of this study was to exploit the possibility of combination of active targeting function of folic acid by folate receptor-mediated endocytosis and overcoming multidrug resistance (MDR) by Pluronic block copolymers to promote drug delivery to MDR tumor following intravenous administration with paclitaxel (PTX) as model drug. Folic acid functionalized Pluronic P123/F127 mixed micelles encapsulating PTX (FPF-PTX) was firstly developed and tested in vitro and in vivo, while PTX-loaded Pluronic P123/F127 mixed micelles (PF-PTX) and Taxol were used as control. FPF-PTX was about 20 nm in diameter with spherical shape and high encapsulation efficiency. Cellular uptake of FPF-PTX was found to be higher than that of PF-PTX due to the folate receptor-mediated endocytosis effect. In vitro cytotoxicity, cell apoptosis and cell cycle arrest studies also revealed that FPF-PTX was more potent than those of PF-PTX and Taxol. In vivo pharmacokinetic study in rats showed that the polymeric micelles significantly enhanced the bioavailability of PTX (∼3 fold) than Taxol. Moreover, in BALB/c mice bearing KBv MDR tumor xenografts, stronger antitumor efficacy was shown in FPF-PTX group, with good correlation between in vitro and in vivo. In conclusion, folate-conjugated Pluronic micelles could be a potential vehicle for delivering hydrophobic chemotherapeutic drugs to MDR tumors.

Paclitaxel-loaded Pluronic P123/F127 mixed polymeric micelles: formulation, optimization and in vitro characterization.

The objective of this study was to optimize and characterize a novel polymeric mixed micelle composed of Pluronic P123 and F127 loaded with paclitaxel (PTX). A Doehlert matrix design was utilized to investigate the effect of four variables, namely P123 mass fraction, amount of water, feeding of PTX and hydration temperature on the responses including drug-loading coefficient (DL %), encapsulation ratio (ER %) and the percentage of PTX precipitated from the drug-loaded mixed micelles after 48 h at 37 (PTX precipitated %) for improvement of drug solubilization efficiency and micelle stability. PTX-loaded P123/F127 mixed micelles were prepared by thin-film hydration method. The optimized formulation showed a particle size of about 25 nm with ER %>90%, and a sustained release behavior compared to Taxol. Micelle formation was confirmed by NMR spectroscopy. The mixed micelles had a low CMC of 0.0059% in water. In addition, micelle stability studies implied that introduction of Pluronic F127 (33 wt%) into P123 micelle system significantly increased the stability of PTX-loaded micelles. More importantly, in vitro cytotoxicity was assessed using human lung adenocarcinoma cell lines SPC-A1 and A-549 and was compared to Taxol and the free drug. The cell viability assay against A-549 cells exhibited the 50% inhibition concentration (IC50) of PTX-loaded P123/F127 mixed micelles (0.1 microg/ml) was much lower than those of Taxol injection (0.4 microg/ml) and the free PTX (1.7 microg/ml). Therefore, PTX-loaded P123/F127 mixed micelles may be considered as an effective anticancer drug delivery system for cancer chemotherapy.

Enhanced antitumor efficacy by Paclitaxel-loaded Pluronic P123/F127 mixed micelles against non-small cell lung cancer based on passive tumor targeting and modulation of drug resistance

The aim of this work was to demonstrate the advantage of using paclitaxel (PTX)-loaded Pluronic P123/F127 mixed micelles (PF-PTX) against non-small cell lung cancer (NSCLC) compared to Taxol. Modulation of multidrug resistance (MDR) by Pluronic mixed micelles was evaluated in lung resistance protein (LRP)-overexpressing human lung adenocarcinoma A-549 cell line. Influence of PF-PTX on in vitro cytotoxicity was determined by MTT assay, while cellular apoptosis was detected by cell nuclei staining and Annexin V-FITC apoptosis detection kit. Cell cycle arrest was also confirmed by flow cytometry. Additionally, in vivo fate and antitumor efficacy of PF-PTX were extensively evaluated in comparison with Taxol. It was demonstrated that PF-PTX had superior anti-proliferation activity against A-549 cells compared with Taxol as measured by IC(50). The enhanced anti-cancer efficacy of PF-PTX was associated with PTX-induced apoptosis and cell arrest in the G(2)/M phase. Intracellular ATP depletion and decreased mitochondrial potential caused by Pluronic copolymers were found to be related to modulation of MDR. PF-PTX also exhibited significant advantages in pharmacokinetics and A-549 xenograft tumor model versus Taxol. The PF-PTX formulation achieved 3.0-fold longer mean residence time in circulation, 2.2-fold larger area under the plasma concentration-time curve than Taxol. At 28days, tumor volume in PF-PTX group was only 31.8% that of the Taxol. Therefore, PF-PTX significantly enhanced the anti-cancer activity of PTX and might be considered a promising drug delivery system to overcome MDR in lung cancer.

Nanoparticles of 2-deoxy-d-glucose functionalized poly(ethylene glycol)-co-poly(trimethylene carbonate) for dual-targeted drug delivery in glioma treatment

Based on the facilitative glucose transporter (GLUT) over-expression on both blood-brain barrier (BBB) and glioma cells, 2-deoxy-d-glucose modified poly(ethylene glycol)-co-poly(trimethylene carbonate) nanoparticles (dGlu-NP) were developed as a potential dual-targeted drug delivery system for enhancing the BBB penetration via GLUT-mediated transcytosis and improving the drug accumulation in the glioma via GLUT-mediated endocytosis. In vitro physicochemical characterization of the dual-targeted nanoparticulate system presented satisfactory size of 71 nm with uniform distribution, high encapsulation efficiency and adequate loading capacity of paclitaxel (PTX). Compared with non-glucosylated nanoparticles (NP), a significantly higher amount of dGlu-NP was internalized by RG-2 glioma cells through caveolae-mediated and clathrin-mediated endocytosis. Both of the transport ratios across the in vitro BBB model and the cytotoxicity of RG-2 cells after crossing the BBB were significantly greater of dGlu-NP/PTX than that of NP/PTX. In vivo fluorescent image indicated that dGlu-NP had high specificity and efficiency in intracranial tumor accumulation. The anti-glioblastoma efficacy of dGlu-NP/PTX was significantly enhanced in comparison with that of Taxol and NP/PTX. Preliminary safety tests showed no acute toxicity to hematological system, liver, kidney, heart, lung and spleen in mice after intravenous administration at a dose of 100 mg/kg blank dGlu-NP per day for a week. Therefore, these results indicated that dGlu-NP developed in this study could be a potential dual-targeted vehicle for brain glioma therapy.

Enhanced anti-glioblastoma efficacy by PTX-loaded PEGylated poly(ɛ-caprolactone) nanoparticles: In vitro and in vivo evaluation.

The aim of this work was to investigate the anti-tumor effect of paclitaxel (PTX)-loaded methoxy poly(ethylene glycol)-poly(ɛ-caprolactone) nanoparticles (MPEG-NP/PTX) against glioblastoma multiforme (GBM). MPEG-NP/PTX was prepared by the emulsion and evaporation technique with particle size of 72.5±2.2nm and did not change remarkably during the period of 21-day storage at 4°C. The drug-loading coefficient and encapsulation ratio of optimized formulation were 8.2±0.6% and 90.4±2.3%, respectively. The in vitro release behavior exhibits a biphase release manner and was affected by PEG segment. In vitro cytotoxicity was assessed using C6 cell lines and was compared to Taxol and PTX-loaded poly(ɛ-caprolactone) conventional nanoparticles (NP/PTX). Cell viability assay against C6 cells exhibited higher or at least comparable cytotoxicity than that of Taxol and NP/PTX. More importantly, in vivo real-time fluorescence imaging analysis in intracranial C6 glioblastoma bearing mice showed that the methoxy poly(ethylene glycol)-poly(ɛ-caprolactone) nanoparticles (MPEG-NP) displayed much stronger fluorescence signal and 3-fold larger Area-Under-Curve (AUC) than poly(ɛ-caprolactone) conventional nanoparticles (NP) in tumor-bearing brain. Furthermore, in vivo anti-glioblastoma effect exhibited the mean survive time of MPEG-NP/PTX (28 days) was much longer than those of Taxol injection (20 days) and NP/PTX (23 days). Therefore, MPEGylated poly(ɛ-caprolactone) nanoparticles significantly enhanced the anti-glioblastoma activity of PTX and might be considered a promising drug delivery system against advanced glioblastoma.

Self-aggregated pegylated poly (trimethylene carbonate) nanoparticles decorated with c(RGDyK) peptide for targeted paclitaxel delivery to integrin-rich tumors

Cyclic RGD peptide-decorated polymeric micellar-like nanoparticles (MNP) based on PEGylated poly (trimethylene carbonate) (PEG-PTMC) were prepared for active targeting to integrin-rich cancer cells. An amphiphilic diblock copolymer, α-carboxyl poly (ethylene glycol)-poly (trimethylene carbonate) (HOOC-PEG-PTMC), was synthesized by ring-opening polymerization. The c(RGDyK) ligand, a cyclic RGD peptide that can bind to the integrin proteins predominantly expressed on the surface of tumor cells with high affinity and specificity, was conjugated to the NHS-Activated PEG terminus of the copolymer. The c(RGDyK)-functionalized PEG-PTMC micellar nanoparticles encapsulating PTX (c(RGDyK)-MNP/PTX) was fabricated by the emulsion/solvent evaporation technique and characterized in terms of morphology, size and zeta potential. Cellular uptake of c(RGDyK)-MNP/PTX was found to be higher than that of MNP/PTX due to the integrin protein-mediated endocytosis effect. In vitro cytotoxicity, cell apoptosis and cell cycle arrest studies also revealed that c(RGDyK)-MNP/PTX was more potent than those of MNP/PTX and Taxol. Pharmacokinetic study in rats demonstrated that the polymeric micellar nanoparticles significantly enhanced the bioavailability of PTX than Taxol. In vivo multispectral fluorescent imaging indicated that c(RGDyK)-MNP/PTX had high specificity and efficiency in tumor active targeting. Therefore, the results demonstrated that c(RGDyK)-decorated PEG-PTMC MNP developed in this study could be a potential vehicle for delivering hydrophobic chemotherapeutic agents to integrin-rich tumors.

The brain targeting mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(ɛ-caprolactone) nanoparticles

In order to evaluate the potential and mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(ε-caprolactone)nanoparticles (ANG-PEG-NP) as brain targeting drug delivery system, Rhodamine B isothiocyanate (RBITC) was used as a fluorescent probe molecule to label ANG-PEG-NP through covalent bonding. The brain transcytosis across the blood-brain barrier (BBB) and brain delivery in mice of RBITC labeled ANG-PEG-NP were investigated in this paper. Results showed that ANG-PEG-NP enhanced significantly the uptake by BCECs compared with that of PEG-NP through caveolae- and clathrin-mediated endocytosis, involving a time-dependent, concentration-dependent and energy-dependent mode. The transport of ANG-PEG-NP across the in vitro BBB model was significantly increased than that of PEG-NP. After injection a dose of 100 mg/kg RBITC labeled ANG-PEG-NP or PEG-NP in mouse caudal vein, the brain coronal section showed a higher accumulation of ANG-PEG-NP in the cortical layer, lateral ventricle, third ventricles and hippocampus than that of PEG-NP. By using an excess of free LRP ligand (Angiopep-2 and/or Aprotinin) as a specific receptor inhibitor, it was evidenced that the uptake by BCECs in vitro, transport across in vitro BBB model and penetration into brain tissue in vivo of RBITC labeled ANG-PEG-NP could be inhibited significantly, which demonstrated the brain targeting mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(ε-caprolactone)nanoparticles might be a LRP receptor mediated transcytosis process. Understanding these issues is important for the future development of ANG-PEG-NP as a brain targeting drug delivery system for neurodegenerative disorders including glioma and Alzheimers disease.

The potential of Pluronic polymeric micelles encapsulated with paclitaxel for the treatment of melanoma using subcutaneous and pulmonary metastatic mice models

The increasing global incidence of malignant melanoma combined with the poor prognosis and low survival rates of patients necessitates the development of new chemotherapeutic strategies. Thus, the objective of this present study was to investigate the therapeutic efficacy of Pluronic polymeric micelles encapsulating paclitaxel (PTX) in both B16F10 melanoma subcutaneous mice model and pulmonary metastatic mice model. Herein, we developed a PTX-loaded polymeric micelles (PF-PTX) consisting of Pluronic P 123 and F127 block copolymers with small particle size (∼25 nm), high encapsulation efficiency (>90%), good stability in lyophilized form and pH-dependent in vitro release. Furthermore, influence of PF-PTX on in vitro cytotoxicity was determined by MTT assay using B16F10 melanoma cell line, while cellular distribution of PF-PTX was detected by confocal microscopy. Additionally, C57BL/6 mice bearing subcutaneous or pulmonary B16F10 melanoma tumors were treated with Taxol or PF-PTX, and antitumor effect was compared. It was found that antitumor efficacy of PF-PTX in both tumor models showed significant tumor growth delay and increased survival. In summary, the simple Pluronic-based nanocarrier could be harnessed for the delivery of anticancer drug to melanoma, with increased therapeutic index.

Pharmacokinetics and biodistribution of polymeric micelles of paclitaxel with Pluronic P123

AbstractAim:To investigate the preparation, in vitro release, in vivo pharmacokinetics and tissue distribution of a novel polymeric micellar formulation of paclitaxel (PTX) with Pluronic P123.Methods:The polymeric micelles of paclitaxel with Pluronic P123 were prepared by a solid dispersion method. The characteristics of micelles including particle size distribution, morphology and in vitro release of PTX from micelles were carried out. PTX-loaded micellar solutions were administered through the tail vein to healthy Sprague-Dawley rats and Kunming strain mice to assess the pharmacokinetics and tissue distribution of PTX, respectively. Taxol, the commercially available intravenous formulation of PTX, was also administered as control.Results:By using a dynamic light scattering sizer and a transmission electron microscopy, it was shown that the PTX-loaded micelles had a mean size of approximately 25 nm with narrow size distribution and a spherical shape. PTX was continuously released from Pluronic P123 micelles in release medium containing 1 mol/L sodium salicylate for 24 h at 37°C. In the pharmacokinetic assessment, t½β and AUC of micelle formulation were 2.3 and 2.9-fold higher than that of Taxol injection. And the PTX-loaded micelles increased the uptake of PTX in the plasma, ovary and uterus, lung, and kidney, but decreased uptake in the liver and brain in the biodistribution study.Conclusion:Polymeric micelles using Pluronic P123 can effectively solubilize PTX, prolong blood circulation time and modify the biodistribution of PTX.