Paclitaxel-loaded polyester nanoparticles prepared by spray-drying technology: in vitro bioactivity evaluation

Paclitaxel (PTX), an antimicrotubular agent used in the treatment of ovarian and breast cancer, was encapsulated in nanoparticles (NPs) of poly(lactide-co-glycolide) (PLGA) and poly(ε-caprolactone) (PCL) polymers using the spray-drying technique. Morphology, size distribution, drug encapsulation efficiency, thermal degradation and drug release were characterized. MCF7 cells were employed to evaluate the efficacy of the systems on cell cycle and cytotoxicity. The particle size was in the range 0.8-1?μm. The incorporation efficiency of PTX was more than 80% in all NPs obtained. In?vitro drug release took place during 35 days, and drug release rates were in the order PCL?>?PLGA 50:50?>?PLGA 75:25. Unloaded NPs showed to be cytocompatible at MCF7 cells. PTX-loaded NPs demonstrated the release of the drug block cells in the G2/M phase. All PTX-loaded formulations showed their efficacy in killing MCF7 cells, mainly PTX-loaded PLGA 50:50 and PLGA 75:25 that cause a decrease in cell viability lower than 20%.     

Pharmacokinetics and biodistribution of polymeric micelles of paclitaxel with pluronic P105/poly(caprolactone) copolymers

A novel polymeric micellar formulation of paclitaxel (PTX) with Pluronic/poly(caprolactone) (P105/ PCL50) has been developed with the purpose of improving in vitro release and in vivo circulating time of PTX in comparison to the current Taxol injection. This study was designed to investigate the preparation, in vitro release, in vivo pharmacokinetics and tissue distribution of the PTX-loaded, biodegradable, polymeric, P105/PCL50 micelle system. The drug-loaded micelles were prepared by dialysis using the hydrophobic drug, PTX, and the nonionic surfactant Pluronic P105 modified with a low molecular weight PCL. The results of dynamic light scattering (DLS) experiment indicated that the PTX-loaded micelles had a mean size of approximately 150 nm with narrow size distribution (polydispersity index < 0.3). The in vitro release study showed that the release of PTX from the micelles exhibited a sustained release behavior. A similar phenomenon was also observed in a pharmacokinetic assessment in rats, in which t1/2 beta and AUC of the PTX micelle formulation were 4.0 and 2.2-fold higher than that of Taxol injection. The biodistribution study in mice showed that the PTX micelle formulation not only decreased drug uptake by the liver, but also prolonged drug retention in the blood, and increased the distribution of drug in kidney, spleen, ovaries and uterus. These results suggested that the P105/ PCL50 polymeric micelles may efficiently load, protect and retain PTX in both in vitro and in vivo environments, and could be a useful drug carrier for i.v. administration of PTX.     

Tamoxifen-loaded nanoparticles based on a novel mixture of biodegradable polyesters: characterization and in vitro evaluation as sustained release systems

Nanoparticles (NP) from mixtures of two poly(D,L-lactide-co-caprolactone) (PLC) copolymers, PLC 40/60 and PLC 86/14, with poly(D,L-lactide) (PDLLA) and PCL were prepared: PLC 40/60-PCL (25:75), PLC 86/14-PCL (75:25) and PLC 86/14-PLA (75:25). Tamoxifen was loaded with encapsulation efficiency between 65% and 75% (29.9-36.3?μg TMX/ mg NP). All selected systems showed spherical shape and nano-scale size. TMX-loaded NPs were in the range of 293-352?nm. TMX release from NP took place with different profiles depending on polymeric composition of the particles. After 60 days, 59.81% and 82.65% of the loaded drug was released. The cytotoxicity of unloaded NP in MCF7 and HeLa cells was very low. Cell uptake of NP took place in both cell types by unspecific internalization in a time dependent process. The administration of 6 and 10?μm TMX by TMX-loaded NP was effective on both cellular types, mainly in MCF7 cells.     

Tamoxifen-loaded nanoparticles based on a novel mixture of biodegradable polyesters: characterization and in vitro evaluation as sustained release systems

Nanoparticles (NP) from mixtures of two poly(D,L-lactide-co-caprolactone) (PLC) copolymers, PLC 40/60 and PLC 86/14, with poly(D,L-lactide) (PDLLA) and PCL were prepared: PLC 40/60-PCL (25:75), PLC 86/14-PCL (75:25) and PLC 86/14-PLA (75:25). Tamoxifen was loaded with encapsulation efficiency between 65% and 75% (29.9–36.3?µg TMX/ mg NP). All selected systems showed spherical shape and nano-scale size. TMX-loaded NPs were in the range of 293–352?nm. TMX release from NP took place with different profiles depending on polymeric composition of the particles. After 60 days, 59.81% and 82.65% of the loaded drug was released. The cytotoxicity of unloaded NP in MCF7 and HeLa cells was very low. Cell uptake of NP took place in both cell types by unspecific internalization in a time dependent process. The administration of 6 and 10?µm TMX by TMX-loaded NP was effective on both cellular types, mainly in MCF7 cells.     

Comparative study of some biodegradable polymers on the entrapment efficiency and release behavior of etoposide from microspheres

Etoposide-loaded biodegradable microspheres of poly lactic-co-glycolide (PLGA) 50:50, PLGA 75:25, and polycaprolactone (PCL) were prepared by simple o/w emulsification solvent evaparation method and characterized by size analysis and microscopy. The influence of drug to polymer ratio on the entrapment of etoposide was studied. Of all the three types of microspheres, polycaprolactone microspheres (PCL MS) showed the highest entrapment efficiency (94.64%), followed by PLGA 75:25 microspheres (PLGA 75:25 MS) (88.64%) and PLGA 50:50 microspheres (PLGA 50:50 MS) (79.19%). The drug to polymer ratio of 1:20 gave the highest entrapment efficiency for all the three types of microspheres. The in vitro release of etoposide from the three microsphere formulations were studied in phosphate buffer pH 7.4 (pH 7.4 PB) containing 0.1% Tween 80. The microspheres showed an initial burst release, which was highest from the PLGA 50:50 MS and least from the PCL MS. PCL MS microspheres showed the lower and slow drug release than the remaining formulations. The release of etoposide from all the three microsphere formulations followed Higuchi's diffusion pattern. The microspheres in the dissolution medium for 28 days appeared irregular in shape and slightly fragmented.     

Pharmacokinetics and biodistribution of paclitaxel-loaded microspheres

Paclitaxel(PTX)-loaded microspheres composed of poly(D,L-lactide-co-glycolide) (PLGA) were prepared by an O/W emulsion solvent evaporation method. This study was designed to investigate the preparation, in vitro release, in vivo pharmacokinetics and tissue distribution of a PTX-loaded microspheres system. Microspheres are characterized according to drug loading, size and shape. With a dynamic light scattering sizer and a transmission electron microscopy, it is shown that the PTX-loaded microspheres had a mean size of approximately 10.24 μm with narrow size distribution and a spherical shape. The in vitro release profiles indicate that the release of PTX from the microspheres exhibit a sustained release behavior. A similar phenomenon is observed in a pharmacokinetic study in rats, in which AUC of the microspheres formulation were 3.7-fold higher than that of PTX injection. The biodistribution study in mice showed that the PTX-loaded microspheres not only decreased drug uptake by liver, but also increased distribution of drug in lung. These results suggest that PTX-loaded microspheres may efficiently load, protect and retain PTX in both in vitro and in vivo environments, and could be a useful drug carrier for i. v. administration of PTX.     

Fabrication of drug-loaded polymer microparticles with arbitrary geometries using a piezoelectric inkjet printing system

Carrier geometry is a key parameter of drug delivery systems and has significant impact on the drug release rate and interaction with cells and tissues. Here we present a piezoelectric inkjet printing system as a simple and convenient approach for fabrication of drug-loaded polymer microparticles with well-defined and controlled shapes. The physical properties of paclitaxel (PTX)-loaded poly(lactic-co-glycolic acid) (PLGA) inks, such as volatility, viscosity and surface tension, were optimized for piezoelectric inkjet printing, and PTX-loaded PLGA microparticles were fabricated with various geometries, such as circles, grids, honeycombs, and rings. The resulting microparticles with 10% (w/w) PTX exhibited a fairly homogeneous shape and size. The microparticle fabrication by piezoelectric inkjet printing was precise, reproducible, and highly favorable for mass production. The microparticles exhibited a biphasic release profile with an initial burst due to diffusion and a subsequent, slow second phase due to degradation of PLGA. The release rate was dependent on the geometry, mainly the surface area, with a descending rate order of honeycomb>grid, ring>circle. The PTX-loaded microparticles showed a comparable activity in inhibiting the growth of HeLa cells. Our results demonstrate that a piezoelectric inkjet printing system would provide a new approach for large-scale manufacturing of drug carriers with a desired geometry.     

Biodistribution and pharmacokinetic analysis of Paclitaxel and ceramide administered in multifunctional polymer-blend nanoparticles in drug resistant breast cancer model

In this study, we have investigated the biodistribution and pharmacokinetic analysis of paclitaxel (PTX) and the apoptotic signaling molecule, C6-ceramide (CER), when administered in a multifunctional polymer-blend nanoparticle formulation to female nude mice bearing an orthotopic drug sensitive MCF7 and multidrug resistant MCF7 TR (MDR-1 positive) human breast adenocarcinoma. A polymer-blend nanoparticle system was engineered to incorporate temporally controlled sequential release of the combination drug payload. Hereby, PTX was encapsulated in the pH-responsive rapid releasing polymer, poly(beta-amino ester) (PbAE), while CER was present in the slow releasing polymer, poly(D,L-lactide-co-glycolide) (PLGA) within these blend nanoparticles. When particle formulations were administered intravenously to MCF7 and MCF7 TR tumor bearing mice, higher concentrations of PTX were found in the blood due to longer retention time and an enhanced tumor accumulation relative to administration of free drug. In addition, the PLGA/PbAE blend nanoparticles were effective in enhancing the residence time of both drugs at the tumor site by reducing systemic clearance. Overall, these results are highly encouraging for development of multifunctional polymer-blend nanoparticle formulations that can be used for temporal-controlled administration of two drugs from a single formulation.     

Development of Nanoparticles for Drug Delivery to Brain Tumor: The Effect of Surface Materials on Penetration Into Brain Tissue

Surface-modified poly(d,l-lactic-co-glycolic acid) PLGA nanoparticles (NPs) were fabricated via nanoprecipitation for obtaining therapeutic concentration of paclitaxel (PTX) in brain tumor. The cellular uptake and cytotoxicity of NPs were evaluated on C6 glioma cells in vitro, and BALB/c mice were used to study the brain penetration and biodistribution upon intravenous administration. Results showed that by finely tuning nanoprecipitation parameters, PLGA NPs coated with surfactants with a size around 150 nm could provide a sustained release of PTX for >2 weeks. Surface coatings could increase cellular uptake efficiency when compared with noncoated NPs, and d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) showed the most significant enhancement. The in vivo evaluation of TPGS-PLGA NPs showed amplified accumulation (>800% after 96 h) of PTX in the brain tissue when compared with bare NPs and Taxol^®. Therefore, PLGA-NPs with PLGA-TPGS coating demonstrate a promising approach to efficiently transport PTX across blood-brain barrier in a safer manner, with the advantages of easy formulation, lower production cost, and higher encapsulation efficiency.     

Hydrotropic Polymeric Mixed Micelles Based on Functional Hyperbranched Polyglycerol Copolymers as Hepatoma-Targeting Drug Delivery System

Mixed copolymer nanoparticles (NPs) self-assembled from β-cyclodextrin-grafted hyperbranched polyglycerol (HPG-g-CD) and lactobionic acid (LA)-grafted hyperbranched polyglycerol (HPG-g-LA) were applied as carriers for a hydrophobic antitumor drug, paclitaxel (PTX), achieving hepatocellular carcinoma-targeted delivery. The resulting NPs exhibited high drug loading capacity and substantial stability in aqueous solution. In vitro drug release studies demonstrated a controlled drug release profile with increased release at acidic pH. Remarkably, tumor proliferation assays showed that PTX-loaded mixed copolymer NPs inhibited asialoglycoprotein (ASGP) receptor positive HepG2 cell proliferation in a concentration-dependent manner in comparison with ASGP receptor negative BGC-823 cells. Moreover, the competition assay demonstrated that the small molecular LA inhibited the cellular uptake of the PTX-loaded mixed copolymer NPs, indicating the ASGP receptor-mediated endocytosis in HepG2 cells. In addition, the intracellular uptake tests by confocal laser scanning microscopy showed that the mixed copolymer NPs were more efficiently taken up by HepG2 cells compared with HPG-g-CD NPs. These results suggest a feasible application of the mixed copolymer NPs as nanocarriers for hepatoma-targeted delivery of potent antitumor drugs.     

Treatments of paclitaxel with poly(vinyl pyrrolidone) to improve drug release from poly(ɛ-caprolactone) matrix for film-based stent

Drug-loaded biodegradable films as a principal part of film-based stent were investigated for controlled drug delivery systems. In this study, solid dispersion technique, a pretreatment method of paclitaxel (PTX), was applied to prepare the PTX-loaded poly(?-caprolactone) (PCL) films. Drug dissolution rates and characteristics of the poly(vinyl pyrrolidone) (PVP)/PTX solid dispersions (SDs) and physical mixtures (PMs) were investigated to show that the PVP/PTX SDs were successfully prepared before being incorporated in biodegradable films. Afterwards, the effect of the application of SDs on improving drug release behavior, weightlessness, crystalline states, and surface and internal morphologies of the films were studied. It was found that, the films with SDs showed a higher drug release rate than the films with PMs or pure PTX. In addition, the content of PVP in the SDs also had impact on drug release behavior: the more PVP in SDs, the faster the drug was released. According to the drug release test and weightlessness study, the possible drug release mechanism was put forward for the films with SDs. The application of solid dispersion technique showed a remarkable effect on improving drug release behavior for film-based biodegradable stent drug delivery systems.     

Paclitaxel-loaded PLGA nanoparticles surface modified with transferrin and Pluronic®P85, an in vitro cell line and in vivo biodistribution studies on rat model

The development of multidrug resistance (due to drug efflux by P-glycoproteins) is a major drawback with the use of paclitaxel (PTX) in the treatment of cancer. The rationale behind this study is to prepare PTX nanoparticles (NPs) for the reversal of multidrug resistance based on the fact that PTX loaded into NPs is not recognized by P-glycoproteins and hence is not effluxed out of the cell. Also, the intracellular penetration of the NPs could be enhanced by anchoring transferrin (Tf) on the PTX-PLGA-NPs. PTX-loaded PLGA NPs (PTX-PLGA-NPs), Pluronic^®P85-coated PLGA NPs (P85-PTX-PLGA-NPs), and Tf-anchored PLGA NPs (Tf-PTX-PLGA-NPs) were prepared and evaluted for cytotoxicity and intracellular uptake using C6 rat glioma cell line. A significant increase in cytotoxicity was observed in the order of Tf-PTX-PLGA-NPs > P85-PTX-PLGA-NPs > PTX-PLGA-NPs in comparison to drug solution. In vivo biodistribution on male Sprague–Dawley rats bearing C6 glioma (subcutaneous) showed higher tumor PTX concentrations in animals administered with PTX-NPs compared to drug solution.     

Doxorubicin-loaded galactose-conjugated poly(d,l-lactide-co-glycolide) nanoparticles as hepatocyte-targeting drug carrier

The objective of this work is to produce doxorubicin-loaded galactose-conjugated poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) to be specifically recognised by human hepatoma cellular carcinoma (Hep G2) cells and assess NPs cytotoxicity. Doxorubicin-unloaded and doxorubicin-loaded galactose-conjugated PLGA NPs were prepared using an emulsion method and characterised for morphology, size, drug release behaviour, Hep G2 recognition and cell cytotoxicity. The produced doxorubicin-loaded PLGA-galactose-conjugate nanoparticles (PLGA-GAL NPs) are spherical in shape with a size of 365?±?74?nm, a drug encapsulation efficiency of 69% and released in a biphasic pattern with higher release rates at pH 5. In vitro cell studies confirmed the specific interaction between the receptors of Hep G2 and the PLGA-GAL NPs. Cell cytotoxicity tests showed that unloaded NPs are non-toxic and that doxorubicin-loaded NPs caused a cellular viability decrease of around 80%, therefore representing a promising approach to improve liver-specific drug delivery.     

Nucleobase-crosslinked poly(2-oxazoline) nanoparticles as paclitaxel carriers with enhanced stability and ultra-high drug loading capacity for breast cancer therapy

Poly(2-oxazoline)(POx) has been regarded as a potential candidate for drug delivery carrier to meet the challenges of nanomedicine clinical translation, due to its excellent biocompatibility and self-assembly properties. The drug loading capacity and stability of amphiphilic POxs as drug nanocarriers, however, tend to be insufficient. Herein, we report a strategy to prepare nucleobase-crosslinked POx nanoparticles(NPs) with enhanced stability and ultra-high paclitaxel(PTX) loading capacity for b...     

Polydopamine-Based Surface Modification for the Development of Peritumorally Activatable Nanoparticles

Purpose

To create poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), where a drug-encapsulating NP core is covered with polyethylene glycol (PEG) in a normal condition but exposes a cell-interactive TAT-modified surface in an environment rich in matrix metalloproteinases (MMPs).

Methods

PLGA NPs were modified with TAT peptide (PLGA-pDA-TAT NPs) or dual-modified with TAT peptide and a conjugate of PEG and MMP-substrate peptide (peritumorally activatable NPs, PANPs) via dopamine polymerization. Cellular uptake of fluorescently labeled NPs was observed with or without a pre-treatment of MMP-2 by confocal microscopy and flow cytometry. NPs loaded with paclitaxel (PTX) were tested against SKOV-3 ovarian cancer cells to evaluate the contribution of surface modification to cellular delivery of PTX.

Results

While the size and morphology did not significantly change due to the modification, NPs modified with dopamine polymerization were recognized by their dark color. TAT-containing NPs (PLGA-pDA-TAT NPs and PANPs) showed changes in surface charge, indicative of effective conjugation of TAT peptide on the surface. PLGA-pDA-TAT NPs and MMP-2-pre-treated PANPs showed relatively good cellular uptake compared to PLGA NPs, MMP-2-non-treated PANPs, and NPs with non-cleavable PEG. After 3 h treatment with cells, PTX loaded in cell-interactive NPs showed greater toxicity than non-interactive ones as the former could enter cells during the incubation period. However, due to the initial burst drug release, the difference was not as clear as microscopic observation.

Conclusions

PEGylated polymeric NPs that could expose cell-interactive surface in response to MMP-2 were successfully created by dual modification of PLGA NPs using dopamine polymerization.     

紫杉醇PLGA纳米粒的处方优化与评价

目的 采用生物可降解材料乳酸-羟基乙酸共聚物(PLGA)为载体,比较不同的制备方法和工艺对紫杉醇(PTX)PLGA纳米粒(PTX-PLGA NPs)粒径的影响,筛选出最优制备工艺,并考察所制备纳米粒的体外表征以及对人源胃癌细胞SGC-7901的抗肿瘤效果,为紫杉醇缓释制剂在胃癌中的开发提供一定的实验基础.方法 采用单因...     

Synthesis,characterization, and kinetic release study of methotrexate loaded mPEG–PCL polymersomes for inhibition of MCF-7 breast cancer cell line

In this study, we designed a polymersome system for the controlled release of methotrexate (MTX) as an anticancer drug with the objective of improving the loading efficiency of the drug in polymersomes as well as achievement of an efficient control on the release rate of drug from nanocarriers. We synthesized mono methoxy poly(ethylene glycol)–poly(e-caprolactone) (mPEG–PCL) diblock copolymers. The structure of the copolymers was characterized by proton nuclear magnetic resonance spectroscopy (¹H NMR), Fourier transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) techniques. MTX was encapsulated within nanoparticles (NPs) through multiple emulsion method. The resulting NPs were characterized further by various techniques such as atomic force microscopy (AFM) and dynamic light scattering (DLS). Next, the various kinetic equations were fitted to the release data of MTX from MTX-loaded mPEG–PCL polymersomes. The results showed that the zeta potential of MTX-loaded mPEG–PCL polymersomes was about –5.49?mV and the average size was 49.18?nm. MTX was encapsulated into polymersomes loading capacity of 12?±?0.09% and encapsulation efficiency of 45.5?±?0.41%. The metabolic activity assays of void of MTX, mPEG–PCL polymersomes, and MTX-loaded mPEG–PCL polymersomes were compared to each other by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay of the treated MCF-7 cell lines. It can be concluded that application of NPs is a better and more effective strategy for controlled and slow release of MTX in the treatment of cancer.     

A novel polyethylene glycol mediated lipid nanoemulsion as drug delivery carrier for paclitaxel

A novel polyethylene glycol 400 (PEG400) mediated lipid nanoemulsion as drug-delivery carrier for paclitaxel (PTX) was successfully developed. The formulation comprised a PEG400 solution of the drug (25 mg/mL) that would be mixed with commercially 20% lipid emulsion to form PTX-loaded nanoemulsion (1 mg/mL) prior to use. This two-vial formulation of PTX-loaded lipid nanoemulsion (TPLE) could significantly reduce extraction of reticuloendothelial system (RES) organs and increase tumor uptake, and exhibited more potent antitumor efficacy on bearing A2780 or Bcap-37 tumor nude mice compared to conventional PTX-loaded lipid nanoemulsion (CPLE). TPLE did not cause haematolysis and intravenous irritation response yet, and showed the same cytotoxicity against HeLa cells as Taxol®, and its LD₅₀ was 2.7-fold higher than that of Taxol®, suggesting its good safety and druggability. In addition, TPLE displayed distinctly faster release of PTX, a greater proportion of PTX in phospholipids layer and a smaller share in oil phase than CPLE. From the Clinical Editor: This study demonstrates the feasibility and potential advantage of a novel PEG400-mediated two-vial formulation of lipid nanoemulsion as drug carrier for PTX in clinical application for the cancer therapy.From the Clinical EditorThis team of investigators convincingly demonstrates the feasibility and potential advantage of a PEG400-mediated two-vial formulation of lipid nanoemulsion as drug carrier for PTX in cancer therapy, documenting superior safety and faster release of PTX compared to commercially available formulations.     

Targeted delivery of monoclonal antibody conjugated docetaxel loaded PLGA nanoparticles into EGFR overexpressed lung tumour cells

The aim of this study was to develop anti-EGFR antibody conjugated poly(lactide-co-glycolide) nanoparticles (NPs) to target epidermal growth factor receptor, highly expressed on non-small cell lung cancer cells to improve cytotoxicity and site specificity. Cetuximab was conjugated to docetaxel (DTX) loaded PLGA NPs by known EDC/NHS chemistry and characterised for size, zeta potential, conjugation efficiency and the results were 128.4?±?3.6?nm, –31.0?±?0.8?mV, and 39.77?±?3.4%, respectively. In vitro release study demonstrated sustained release of drug from NPs with 25% release at pH 5.5 after 48?h. In vitro cytotoxicity studies demonstrated higher anti-proliferative activity of NPs than unconjugated NPs. Cell cycle analysis and apoptosis study were performed to evaluate extent of cell arrest at different phases and apoptotic potential for the formulations, respectively. In vivo efficacy study showed significant reduction in tumour growth and so antibody conjugated NPs present a promising active targeting carrier for tumour selective therapeutic treatment.     

Novel self-assembling PEG-p-(CL-co-TMC) polymeric micelles as safe and effective delivery system for Paclitaxel

Paclitaxel (PTX) is an effective anti-cancer drug currently used to treat a wide variety of cancers. Unfortunately, nonaqueous vehicle containing Cremophor^® EL is associated with serious clinical side effects. This work aimed to evaluate the ability of polymeric micelles to (i) solubilize PTX without Cremophor^® EL and to be used as a (ii) safe and (iii) effective delivery system for PTX. Hence, we developed novel self-assembling poly(ethyleneglycol)₇₅₀-block-poly(ε-caprolactone-co-trimethylenecarbonate) (PEG-p-(CL-co-TMC)) polymeric micelles which form micelles spontaneously in aqueous solution. The solubility of PTX increased up to three orders of magnitude. The PTX-loaded micelles showed a slow release of PTX with no burst effect. The HeLa cells viability assessed by the MTT test was lower for PTX-loaded micelles than for Taxol^® (IC₅₀ 10.6 vs. 17.6 μg/ml). When solubilized in micelles, PTX induced apoptosis comparable with Taxol^®. The maximum tolerated doses (MTD) of PTX-loaded micelles and Taxol^® in mice were 80 mg/kg and 13.5 mg/kg, respectively, after intraperitoneal administration; and 45 mg/kg and 13.5 mg/kg, respectively, after intravenous administration. Similar anti-tumor efficacy of PTX-loaded micelles and Taxol^® was observed at the dose of 13.5 mg/kg on TLT-tumor-bearing mice, while the body weight loss was only observed in Taxol^® group. However, as higher dose was tolerated (80 mg/kg – IP), a higher growth delay was induced with PTX-loaded micelles. These results demonstrated that PTX-loaded self-assembling micelles present a similar anti-tumor efficacy as Taxol^®, but significantly reduced the toxicity allowing the increase in the dose for better therapeutic response.