Drug Delivery In Cancer Chemotherapy Research Articles

A 3D numerical model of controlled drug delivery to solid tumor by means of mild microwave hyperthermia-activated thermo-sensitive liposomes

A computational 3D analysis of liposomal drug delivery to investigate the effectiveness of this innovative therapy as an alternative to conventional chemotherapy is shown in this study. The temperature field evolution is obtained via the Local Thermal Non-Equilibrium (LTNE) bioheat model by including both variable porosity and blood vessels sizes to describe the local structure of the investigated tissue. Heating is induced by means of a microwave antenna directly inserted in tumor tissue, supplying a pulsating power to avoid tissue necrosis. Interstitial flow and drug diffusion are modeled by means of Darcy's law and convection-diffusion equations, respectively; Starling's law is included to simulate transcapillary exchange. After validating the model with available literature data, the results show that liposomal drug delivery leads to a 10% improvement in therapeutic outcomes (i.e., Fraction of Killed Cells, FKC). It is also proved that considering blood flow in the LTNE porous media model yields a more realistic evolution of drug diffusion and subsequent FKC, while severe tissue damage is avoided because of the pulsating power supply. This study highlights the potential benefits of using liposomal drug delivery in cancer chemotherapy via microwave-induced heating.

Protein-Gated Upconversion Nanoparticle-Embedded Mesoporous Silica Nanovehicles via Diselenide Linkages for Drug Release Tracking in Real Time and Tumor Chemotherapy.

Two novel stimuli-responsive drug delivery systems (DDSs) were successfully created from bovine serum albumin- or myoglobin-gated upconversion nanoparticle-embedded mesoporous silica nanovehicles (UCNP@mSiO2) via diselenide (Se-Se)-containing linkages. More importantly, multiple roles of each scaffold of the nanovehicles were achieved. The controlled release of the encapsulated drug doxorubicin (DOX) within the mesopores was activated by triple stimuli (acidic pH, glutathione, or H2O2) of tumor microenvironments, owing to the conformation/surface charge changes in proteins or the reductive/oxidative cleavages of the Se-Se bonds. Upon release of DOX, the Förster resonance energy transfer between the UCNP cores and encapsulated DOX was eliminated, resulting in an increase in ratiometric upconversion luminescence for DOX release tracking in real time. The two protein-gated DDSs showed some differences in the drug release performances, relevant to structures and properties of the protein nanogates. The introduction of the Se-Se linkages not only increased the versatility of reductive/oxidative cleavages but also showed less cytotoxicity to all cell lines. The DOX-loaded protein-gated nanovehicles showed the inhibitory effect on tumor growth in tumor-bearing mice and negligible damage/toxicity to the normal tissues. The constructed nanovehicles in a spatiotemporally controlled manner have fascinating prospects in targeted drug delivery for cancer chemotherapy.

Ultrafast Low-Temperature Photothermal Therapy Activates Autophagy and Recovers Immunity for Efficient Antitumor Treatment.

Conventional therapeutic approaches to treat malignant tumors such as surgery, chemotherapy, or radiotherapy often lead to poor therapeutic results, great pain, economic burden, and risk of recurrence and may even increase the difficulty in treating the patient. Long-term drug administration and systemic drug delivery for cancer chemotherapy would be accompanied by drug resistance or unpredictable side effects. Thus, the use of photothermal therapy, a relatively rapid tumor elimination technique that regulates autophagy and exerts an antitumor effect, represents a novel solution to these problems. Heat shock protein 90 (HSP90), a protein that reduces photothermal or hypothermic efficacy, is closely related to AKT (protein kinase B) and autophagy. Therefore, it was hypothesized that autophagy could be controlled to eliminate tumors by combining exogenous light with a selective HSP90 inhibitor, for example, SNX-2112. In this study, an efficient tumor-killing strategy using graphene oxide loaded with SNX-2112 and folic acid for ultrafast low-temperature photothermal therapy (LTPTT) is reported. A unique mechanism that achieves remarkable therapeutic performance was discovered, where overactivated autophagy induced by ultrafast LTPTT led to direct apoptosis of tumors and enabled functional recovery of T cells to promote natural immunity for actively participating in the attack against tumors. This LTPTT approach resulted in residual tumor cells being rendered in an "injured" state, opening up the possibility of concurrent antitumor and antirecurrence treatment.

Synthetic dimeric-drug phospholipid: a versatile liposomal platform for cancer therapy.

An amphiphilic dimeric-podophyllotoxin (PODO) phospholipid was synthesized to assemble into liposomes as a combination of prodrug and nanocarrier. The results have demonstrated that the cell membrane-like delivery system possessed an improved cellular uptake and favorable antitumor efficacy with reduced side-effects. This strategy provides a new effective platform in drug delivery for cancer chemotherapy.

Liposome Drug Delivery in Cancer Chemotherapy: Review and Multifactorial Analysis

We reviewed the use of liposomes for cancer therapy using computational biostatistics. We used virtual libraries, such as PubMed, LILACS, National Health Institute (NHI) and the Food Drug Administration (FDA) to conduct the review. Cluster analysis and correlation were developed using the Tanimoto coefficient (TC) of 0.7 using the modeling tool ChemMine Tools from databases (PubChem, DailyMed, DrugBank, Drug @ FDA). The results pointed fifteen molecules in the pharmaceutical form of liposome for the oncological clinic. Of these, 13 are classified by size into small-molecules and were analyzed by computational statistical modeling. Of these, only 4 were approved for use by the FDA, and 9 are in phases of research by the pharmaceutical industry as liposomal formulations. Essential differences in physical-chemical properties and molecules structure were observed, indicating original proposal in the development of liposomal as an anticancer drugs.

Acoustic disruption of tumor endothelium and on-demand drug delivery for cancer chemotherapy

Chemotherapy has been the most widely used treatment against cancer, however, it is limited by its systemic toxicity as well as resistance developed by tumors’ physical barriers. Herein, we propose a novel acoustically-mediated treatment regime to on-demand release therapeutics and disrupt tumor structures. By programming a high intensity focused ultrasound transducer, we can locally and digitally release gemcitabine (GEM) as well as open the local blood–tumor barrier or even tumor stroma to enhance intratumor drug delivery via acoustically-oscillating bubbles and liposomes. In our experiments, we modeled tumor endothelium by culturing a monolayer of murine endothelial cells (2H11) on transwell membrane. We locally disrupted the cultured endothelium to enhance drug penetration by using perfluorocarbon liquid droplets as breaking probes and protoporphyrin IX hybridized liposomes as drug carriers. We also demonstrated an on-demand release of GEM by digitally triggering the break of drug carriers. Moreover, we validated the acoustic tumor endothelium disruption in vivo by monitoring penetration of dye (Evans blue) in solid tumors. Therefore, we present an acoustically-mediated delivery method that both releases drug on-demand locally and opens the blood–tumor barrier to enhance drug penetration. This sets the ground for further clinical cancer therapy to improve many systemic cancer treatments.

Magnetically assisted intraperitoneal drug delivery for cancer chemotherapy

Intraperitoneal (IP) chemotherapy has revived hopes during the past few years for the management of peritoneal disseminations of digestive and gynecological cancers. Nevertheless, a poor drug penetration is one key drawback of IP chemotherapy since peritoneal neoplasms are notoriously resistant to drug penetration. Recent preclinical studies have focused on targeting the aberrant tumor microenvironment to improve intratumoral drug transport. However, tumor stroma targeting therapies have limited therapeutic windows and show variable outcomes across different cohort of patients. Therefore, the development of new strategies for improving the efficacy of IP chemotherapy is a certain need. In this work, we propose a new magnetically assisted strategy to elevate drug penetration into peritoneal tumor nodules and improve IP chemotherapy. A computational model was developed to assess the feasibility and predictability of the proposed active drug delivery method. The key tumor pathophysiology, including a spatially heterogeneous construct of leaky vasculature, nonfunctional lymphatics, and dense extracellular matrix (ECM), was reconstructed in silico. The transport of intraperitoneally injected magnetic nanoparticles (MNPs) inside tumors was simulated and compared with the transport of free cytotoxic agents. Our results on magnetically assisted delivery showed an order of magnitude increase in the final intratumoral concentration of drug-coated MNPs with respect to free cytotoxic agents. The intermediate MNPs with the radius range of 200–300 nm yield optimal magnetic drug targeting (MDT) performance in 5–10 mm tumors while the MDT performance remains essentially the same over a large particle radius range of 100–500 nm for a 1 mm radius small tumor. The success of MDT in larger tumors (5–10 mm in radius) was found to be markedly dependent on the choice of magnet strength and tumor-magnet distance while these two parameters were less of a concern in small tumors. We also validated in silico results against experimental results related to tumor interstitial hypertension, conventional IP chemoperfusion, and magnetically actuated movement of MNPs in excised tissue.

Formulation and In-Vitro Evaluation of Niosomal drug Delivery in Cancer Chemotherapy

Drug delivery systems are defined as formulations aim for transportation of a drug to the desired area of action within the body. The aim of the study was to investigate the feasibility of using Niosomes as a drug delivery system for Cisplatin By entrapment of drug in Niosomes, dose also could be reduced. Niosomes were prepared by Ethanol injection method using cholesterol and Surfactant. Particle size, zeta potential, entrapment efficiency and in vitro drug release studies were performed. The targeted niosome delivery system is composed of drug, surfactant and cholesterol. With regard to the influence of formulation variables on the percent drug loading (PDL), different compositions with varying ratios of surfactant and cholesterol were studied. In –Vitro drug release mechanism was studied for 24 hours.

Acid-Cleavable Unimolecular Micelles from Amphiphilic Star Copolymers for Triggered Release of Anticancer Drugs.

In this contribution, amphiphilic star copolymers (H40-star-PCL-a-PEG) with an H40 hyperbranched polyester core and poly(ε-caprolactone)-a-poly(ethylene glycol) copolymer arms linked with acetal groups are synthesized using ring-opening polymerization and a copper (I)-catalyzed alkyne-azide cycloaddition click reaction. The acid-cleavable acetal groups between the hydrophilic and hydrophobic segments of the arms endow the amphiphilic star copolymers with pH responsiveness. In aqueous solution, unimolecular micelles can be formed with good stability and a unique acid degradability, as is desirable for anticancer drug carriers. For the model drug of doxorubicin, the in vitro release behavior, intracellular release, and inhibition of proliferation of HeLa cells show that the acid-cleavable unimolecular micelles with anticancer activity can be dissociated in an acidic environment and efficiently internalized by HeLa cells. Due to the acid-cleavable and biodegradable nature, unimolecular micelles from amphiphilic star copolymers are promising for applications in intracellular drug delivery for cancer chemotherapy.

Comparison of Two Approaches for the Attachment of a Drug to Gold Nanoparticles and Their Anticancer Activities.

Drug attachment is important in drug delivery for cancer chemotherapy. The elucidation of the release mechanism and biological behavior of a drug is essential for the design of delivery systems. Here, we used a hydrazone bond or an amide bond to attach an anticancer drug, doxorubicin (Dox), to gold nanoparticles (GNPs) and compared the effects of the chemical bond on the anticancer activities of the resulting Dox-GNPs. The drug release efficiency, cytotoxicity, subcellular distribution, and cell apoptosis of hydrazone-linked HDox-GNPs and amide-linked SDox-GNPs were evaluated in several cancer cells. HDox-GNPs exhibited greater potency for drug delivery via triggered release comediated by acidic pH and glutathione (GSH) than SDox-GNPs triggered by GSH alone. Dox released from HDox-GNPs was released in lysosomes and exerted its drug activity by entering the nuclei. Dox from SDox-GNPs was mainly localized in lysosomes, significantly reducing its efficacy against cancer cells. In addition, in vivo studies in tumor-bearing mice demonstrated that HDox-GNPs and SDox-GNPs both accumulate in tumor tissue. However, only HDox-GNPs enhanced inhibition of subcutaneous tumor growth. This study demonstrates that HDox-GNPs display significant advantages in drug release and antitumor efficacy.

"Sheddable" PEG-lipid to balance the contradiction of PEGylation between long circulation and poor uptake.

PEGylated lipids confer longer systemic circulation and tumor accumulation via the enhanced permeability and retention (EPR) effect. However, PEGylation inhibits cellular uptake and subsequent endosomal escape. In order to balance the contradiction between the advantages of long circulation and the disadvantages of poor uptake of PEGylated lipids, we prepared a "sheddable" PEG-lipid micelle system based on the conjugation of PEG and phosphatidyl ethanolamine (DSPE) with a pH sensitive benzoic imine bond. In a physiological environment, the PEG-protected micelles were not readily taken up by the reticuloendothelial system (RES) and could be successfully delivered to tumor tissue by the EPR effect. In a tumor acidic microenvironment, the PEG chains detached from the surfaces of the micelles while the degree of linker cleavage could not cause a significant particle size change, which facilitated the carrier binding to tumor cells and improved the cellular uptake. Subsequently, the "sheddable" PEG-lipid micelles easily internalized into cells and the increased acidity in the lysosomes further promoted drug release. Thus, this "sheddable" PEG-lipid nanocarrier could be a good candidate for effective intracellular drug delivery in cancer chemotherapy.

A magnetic anti-cancer compound for magnet-guided delivery and magnetic resonance imaging.

Research on controlled drug delivery for cancer chemotherapy has focused mainly on ways to deliver existing anti-cancer drug compounds to specified targets, e.g., by conjugating them with magnetic particles or encapsulating them in micelles. Here, we show that an iron-salen, i.e., μ-oxo N,N'- bis(salicylidene)ethylenediamine iron (Fe(Salen)), but not other metal salen derivatives, intrinsically exhibits both magnetic character and anti-cancer activity. X-Ray crystallographic analysis and first principles calculations based on the measured structure support this. It promoted apoptosis of various cancer cell lines, likely, via production of reactive oxygen species. In mouse leg tumor and tail melanoma models, Fe(Salen) delivery with magnet caused a robust decrease in tumor size, and the accumulation of Fe(Salen) was visualized by magnetic resonance imaging. Fe(Salen) is an anti-cancer compound with magnetic property, which is suitable for drug delivery and imaging. We believe such magnetic anti-cancer drugs have the potential to greatly advance cancer chemotherapy for new theranostics and drug-delivery strategies.

Development, characterization and toxicological evaluations of phospholipids complexes of curcumin for effective drug delivery in cancer chemotherapy

The purpose of this study was to prepare and characterize the complexes between curcumin (CU) phosphatidylcholine (PC) and hydrogenated soya phosphatidylcholine (HSPC) and to evaluate their anticancer activity. These CU–PC and CU–HSPC complexes (CU–PC-C and CU–HSPC-C) were evaluated for various physical parameters like Fourier transform infrared spectroscopy, melting point, solubility, scanning electron microscopy and the in vitro drug release study. These data confirmed the formation of phospholipids complexes. The in vitro hemolysis study showed that the complex was non-hemolytic. The anti-cancer potential of the complexes was demonstrated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay in MCF-7 cell line. This increase may be due to the amphiphilic nature of the complexes, which significantly enhances the water and lipid solubility of the CU. Unlike the free CU (which showed a total of only 90% drug release at the end of 8 h), complex showed around 40–60% release at the end of 8 h in dissolution studies. It showed that (when given in equimolar doses) complexes have significantly decreased the amount of CU available for absorption as compared with CU-free drug. Both CU-PC-C and CU-HSPC-C were found to be non-toxic at the dose equivalent to 2000 mg/kg of body weight of CU in the toxicity study. Acute and subacute toxicity studies confirmed the oral safety of the formulation. A series of genotoxicity studies was conducted, which revealed the non-genotoxicity potential of the developed complexes. Thus, it can be concluded that the phospholipid complexes of CU may be a promising candidate in cancer therapy.

Folate and CD44 Receptors Dual-Targeting Hydrophobized Hyaluronic Acid Paclitaxel-Loaded Polymeric Micelles for Overcoming Multidrug Resistance and Improving Tumor Distribution

The drug efflux mediated by P-glycoprotein (P-gp) transporter is one of the important factors responsible for multidrug resistance (MDR), and then the efficient intracellular drug delivery is an important strategy to overcome MDR of tumor cells. We describe and compare CD44 receptor single-targeting and folate (FA), CD44 receptors dual-targeting hyaluronic acid-octadecyl (HA-C18 ) micellar formulations to overcome MDR of tumor cells and to improve tumor distribution. In comparison with Taxol solution, the cytotoxicity of paclitaxel (PTX) loaded in HA-C18 and FA-HA-C18 micelles against drug-resistant tumor cells was improved significantly because of the increased intracellular delivery by active receptor-mediated endocytosis. Compared with the single-targeting micelles, dual-targeting micelles possessed better MDR-overcoming performance. Pharmacokinetic study demonstrated HA-C18 and FA-HA-C18 PTX-loaded micelles possessed much longer circulation and moderately larger AUC than Taxol solution. Above all, the tumor distribution in MCF-7 tumor-bearing mice of PTX encapsulated in HA-C18 and FA-HA-C18 micelles were 2.8 and 4.0 times higher than that of Taxol solution. It was concluded that dual-targeting FA-HA-C18 micelles demonstrate excellent MDR-overcoming ability and improved tumor distribution, and provide a novel effective nanoplatform for anticancer drug delivery in cancer chemotherapy.

Optimal robust control of drug delivery in cancer chemotherapy: A comparison between three control approaches

During the drug delivery process in chemotherapy, both of the cancer cells and normal healthy cells may be killed. In this paper, three mathematical cell-kill models including log-kill hypothesis, Norton–Simon hypothesis and Emax hypothesis are considered. Three control approaches including optimal linear regulation, nonlinear optimal control based on variation of extremals and H∞-robust control based on μ-synthesis are developed. An appropriate cost function is defined such that the amount of required drug is minimized while the tumor volume is reduced. For the first time, performance of the system is investigated and compared for three control strategies; applied on three nonlinear models of the process. In additions, their efficiency is compared in the presence of model parametric uncertainties. It is observed that in the presence of model uncertainties, controller designed based on variation of extremals is more efficient than the linear regulation controller. However, H∞-robust control is more efficient in improving robust performance of the uncertain models with faster tumor reduction and minimum drug usage.

Research Spotlight: Applications of Ultrasound for image-guided Drug Delivery in Cancer Chemotherapy

Many challenges persist in the field of cancer drug delivery. The field of image-guided drug delivery emerged from the need for accurate in vivo quantification of various pharmacokinetic and therapeutic delivery parameters. Today it continues to be an essential tool in delivery system R&D while providing innovative noninvasive strategies for advancement. This article will focus specifically on the role of ultrasound in this area. Ultrasound provides a novel means by which drugs can be delivered through guided placement of a local delivery device, or through the destruction of ultrasound contrast agents at the target location. The techniques developed by our research group have examined these areas and have also led to a more thorough understanding into the parameters that affect drug release kinetics in vivo from in situ-forming implants. In addition, we have developed a new ultrasound contrast agent capable of extravascular delivery to tumors for improved detection and eventual treatment. Both areas will be discussed in this research spotlight.

Thiol and pH dual-responsive dynamic covalent shell cross-linked micelles for triggered release of chemotherapeutic drugs

We report on the fabrication of dynamic covalent shell cross-linked (SCL) micelles of amphiphilic diblock copolymers functionalized with aldehyde moieties in the hydrophilic block by utilizing difunctional crosslinkers cleavable in response to pH and thiols. Well-defined amphiphilic diblock copolymer, PCL-b-P(OEGMA-co-MAEBA), was synthesized via ring opening polymerization (ROP) of ε-caprolactone (CL) and atom transfer radical polymerization (ATRP) of oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA) and p-(methacryloxyethoxy)benzaldehyde (MAEBA) comonomers. In aqueous solution, the diblock copolymer self-assembles into micelles consisting of hydrophobic PCL cores and hydrophilic P(OEGMA-co-MAEBA) coronas covalently anchored with aldehyde groups. The subsequent shell cross-linking reaction was conducted at pH 6.2 upon addition of difunctional dithiolbis(propanoic dihydrazide) (DTP). The formation of dynamic acylhydrazone cross-linking linkages was facilitated under the catalysis of aniline. The obtained SCL micelles can be de-crosslinked via two biologically relevant modes, namely, acidic pH-triggered cleavage of acylhydrazone bonds into aldehyde and hydrazide and thiol-triggered cleavage of disulfide linkages, which have been utilized for triggered release of physically encapsulated chemotherapeutic drugs. The dual-responsive dynamic covalent SCL micelles were examined by dynamic laser light scattering (LLS), 1H NMR, Ellman's assay, and enzymatic degradation tests. In addition, camptothecin (CPT)-loaded SCL micelles were used to investigate thiol and pH-modulated CPT release profiles. Compared with CPT-loaded non-cross-linked (NCL) micelles, CPT-loaded SCL micelles can largely minimize drug leakage under physiological conditions, whilst exhibiting accelerated drug release under mildly acidic or thiol-rich microenvironments, which are relevant to those of acidic organelles (endosomes and lysosomes) or cytosol within tumor cells. Cell cytotoxicity studies revealed that drug-free SCL micelles are almost nontoxic, whereas CPT-loaded SCL micelles can efficiently deliver chemotherapeutic drug (CPT) into HepG2 cells, leading to considerable nucleic accumulation at extended incubation duration. The reported dynamic covalent shell cross-linking strategy can exert intricate control concerning the micellar stability and the release profile of encapsulated drugs in response to biological microenvironments, which augurs well for their potential use as novel smart nanocarriers for drug delivery in cancer chemotherapy.

Evaluation of triblock copolymeric micelles of δ- valerolactone and poly (ethylene glycol) as a competent vector for doxorubicin delivery against cancer

BackgroundSpecific properties of amphiphilic copolymeric micelles like small size, stability, biodegradability and prolonged biodistribution have projected them as promising vectors for drug delivery. To evaluate the potential of δ-valerolactone based micelles as carriers for drug delivery, a novel triblock amphiphilic copolymer poly(δ-valerolactone)/poly(ethylene glycol)/poly(δ-valerolactone) (VEV) was synthesized and characterized using IR, NMR, GPC, DTA and TGA. To evaluate VEV as a carrier for drug delivery, doxorubicin (DOX) entrapped VEV micelles (VEVDMs) were prepared and analyzed for in vitro antitumor activity.ResultsVEV copolymer was successfully synthesized by ring opening polymerization and the stable core shell structure of VEV micelles with a low critical micelle concentration was confirmed by proton NMR and fluorescence based method. Doxorubicin entrapped micelles (VEVDMs) prepared using a modified single emulsion method were obtained with a mean diameter of 90 nm and high encapsulation efficiency showing a pH dependent sustained doxorubicin release. Biological evaluation in breast adenocarcinoma (MCF7) and glioblastoma (U87MG) cells by flow cytometry showed 2-3 folds increase in cellular uptake of VEVDMs than free DOX. Block copolymer micelles without DOX were non cytotoxic in both the cell lines. As evaluated by the IC50 values VEVDMs induced 77.8, 71.2, 81.2% more cytotoxicity in MCF7 cells and 40.8, 72.6, 76% more cytotoxicity in U87MG cells than pristine DOX after 24, 48, 72 h treatment, respectively. Moreover, VEVDMs induced enhanced apoptosis than free DOX as indicated by higher shift in Annexin V-FITC fluorescence and better intensity of cleaved PARP. Even though, further studies are required to prove the efficacy of this formulation in vivo the comparable G2/M phase arrest induced by VEVDMs at half the concentration of free DOX confirmed the better antitumor efficacy of VEVDMs in vitro.ConclusionsOur studies clearly indicate that VEVDMs possess great therapeutic potential for long-term tumor suppression. Furthermore, our results launch VEV as a promising nanocarrier for an effective controlled drug delivery in cancer chemotherapy.

Nuclear drug delivery for cancer chemotherapy

Nanosystems with unique physical and biological properties have been extensively explored for cancer targeted intracellular delivery of small-molecular chemotherapeutic drugs to increase their therapeutic efficacies and to minimize their side effects. A large number of anticancer drugs are DNA-toxins that bind nuclear DNA or its associated enzymes to exert their cytotoxicity to cancer cells. After entering tumor cells, they need to be further delivered to the nucleus for actions. Herein, we discuss the biological barriers and summarize recent progress of nuclear drug delivery for cancer chemotherapy, emphasizing strategies that appear useful for design of vehicles capable of delivering drugs to the nucleus, particularly for in vivo applications. The existing obstacles or problems that need to be overcome before successful applications of nuclear drug delivery for cancer chemotherapy are also discussed.

Preparation of Core Cross-Linked PCL-PEG-PCL Micelles for Doxorubicin Delivery In Vitro

Doxorubicin has been widely used in cancer treatment, but its severe side-effects restrict its clinical application greatly. So, we hope to design a novel delivery system to decrease its side-effects. In this paper, we prepared core cross-linked micelle based on poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) (CCPCEC) at about 30 nm in diameter with a narrow distribution. The prepared core cross-linked PCL-PEG-PCL micelles were employed to load doxorubicin by pH-induced self-assembly method. Doxorubicin-loading did not obviously affect the micelle size or size distribution. Furthermore, these micelles exhibited a significantly enhanced thermodynamic stability against dilution with aqueous solvents and showed CMC in the range of 1 x 10(-3) to 2 x 10(-3) mg/mL. Cytotoxicity study confirmed great biocompatibility of the micelles and showed that the encapsulated doxorubicin in CCPCEC micelles enhanced the cytotoxicity of doxorubicin on C26 cell line in vitro. Moreover, in vitro release profile demonstrated a significant difference between rapid release of free doxorubicin and much slower and sustained release of doxorubicin-loaded core cross-linked micelles. In addition, a faster DOX-release from micelles at pH 5.5 than that at pH 7.4 was also observed. These results suggested that this new biodegradable Core Cross-linked PCL-PEG-PCL Micelles might be potential carriers for drug delivery in cancer chemotherapy.