TPGS Decorated Liposomes as Multifunctional Nano-Delivery Systems

Liposomes are sphere-shaped vesicles that can capture therapeutics either in the outer phospholipid bilayer or inner aqueous core. Liposomes, especially when surface-modified with functional materials, have been used to achieve many benefits in drug delivery, including improving drug solubility, oral bioavailability, pharmacokinetics, and delivery to disease target sites such as cancers. Among the functional materials used to modify the surface of liposomes, the FDA-approved non-ionic surfactant D-alpha-tocopheryl polyethylene glycol succinate (TPGS) is increasingly being applied due to its biocompatibility, lack of toxicity, applicability to various administration routes and ability to enhance solubilization, stability, penetration and overall pharmacokinetics. TPGS decorated liposomes are emerging as a promising drug delivery system for various diseases and are expected to enter the market in the coming years. In this review article, we focus on the multifunctional properties of TPGS-coated liposomes and their beneficial therapeutic applications, including for oral drug delivery, vaccine delivery, ocular administration, and the treatment of various cancers. We also suggest future directions to optimise the manufacture and performance of TPGS liposomes and, thus, the delivery and effect of encapsulated diagnostics and therapeutics.

A spotlight on alkaloid nanoformulations for the treatment of lung cancer

Numerous naturally available phytochemicals have potential anti-cancer activities due to their vast structural diversity. Alkaloids have been extensively used in cancer treatment, especially lung cancers, among the plant-based compounds. However, their utilization is limited by their poor solubility, low bioavailability, and inadequacies such as lack of specificity to cancer cells and indiscriminate distribution in the tissues. Incorporating the alkaloids into nanoformulations can overcome the said limitations paving the way for effective delivery of the alkaloids to the site of action in sufficient concentrations, which is crucial in tumor targeting. Our review attempts to assess whether alkaloid nanoformulation can be an effective tool in lung cancer therapy. The mechanism of action of each alkaloid having potential is explored in great detail in the review. In general, Alkaloids suppress oncogenesis by modulating several signaling pathways involved in multiplication, cell cycle, and metastasis, making them significant component of many clinical anti-cancerous agents. The review also explores the future prospects of alkaloid nanoformulation in lung cancer. So, in conclusion, alkaloid based nanoformulation will emerge as a potential gamechanger in treating lung cancer in the near future.

Do Lipid-based Nanoparticles Hold Promise for Advancing the Clinical Translation of Anticancer Alkaloids?

Since the commercialization of morphine in 1826, numerous alkaloids have been isolated and exploited effectively for the betterment of mankind, including cancer treatment. However, the commercialization of alkaloids as anticancer agents has generally been limited by serious side effects due to their lack of specificity to cancer cells, indiscriminate tissue distribution and toxic formulation excipients. Lipid-based nanoparticles represent the most effective drug delivery system concerning clinical translation owing to their unique, appealing characteristics for drug delivery. To the extent of our knowledge, this is the first review to compile in vitro and in vivo evidence of encapsulating anticancer alkaloids in lipid-based nanoparticles. Alkaloids encapsulated in lipid-based nanoparticles have generally displayed enhanced in vitro cytotoxicity and an improved in vivo efficacy and toxicity profile than free alkaloids in various cancers. Encapsulated alkaloids also demonstrated the ability to overcome multidrug resistance in vitro and in vivo. These findings support the broad application of lipid-based nanoparticles to encapsulate anticancer alkaloids and facilitate their clinical translation. The review then discusses several limitations of the studies analyzed, particularly the discrepancies in reporting the pharmacokinetics, biodistribution and toxicity data. Finally, we conclude with examples of clinically successful encapsulated alkaloids that have received regulatory approval and are undergoing clinical evaluation.

High expression of ladinin-1 (LAD1) predicts adverse outcomes: a new candidate docetaxel resistance gene for prostatic cancer (PCa)

Docetaxel resistance is one of the major obstacles that undermine the treatment outcome of PCa. Exploring molecular mechanisms associated with docetaxel resistance could provide insights into the formulation of novel strategies enhancing the efficacy of PCa treatment. Ladinin-1 (LAD1) is an anchoring filament protein in basement membranes, which contributes to the association of the epithelial cells with the underlying mesenchyme. LAD1 has been implicated in the progression of different cancers. However, its role in PCa remains to be investigated. In the present study, we found that LAD1 was highly expressed in docetaxel-resistant PCa cells, while its expression was significantly suppressed in tumor samples after docetaxel treatment. Moreover, the expression level of LAD1 in PCa tissues was significantly higher than that of normal tissue, and high expression level of LAD1 was significantly associated with adverse outcomes of PCa patients. Finally, high expression of LAD1 in PCa tissue was also correlated with the expression level of genes involving in tumor cell proliferation and invasive behaviors. Collectively, our data suggest that LAD1 may serve as a potential prognostic factor in PCa patients.

l-Carnitine conjugated chitosan-stearic acid polymeric micelles for improving the oral bioavailability of paclitaxel

A delivery system based on l-carnitine (LC) conjugated chitosan (CS)-stearic acid polymeric micelles has been developed for improving the oral bioavailability of paclitaxel (PTX) through targeting intestinal organic cation/carnitine transporter 2 (OCTN2). Stearic acid grafted chitosan (CS-SA), as micelle skeleton material, was synthesized by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. The PTX-loaded micelles were prepared by solvent evaporation-hydration method, and the ligand LC was conjugated onto the micelle surface by anchoring its derivative stearoyl group to the lipophilic core of micelle. The modified polymeric micelles showed regular spherical shapes with small particle size of 157.1 ± 5.2 nm and high drug loading capacity of 15.96 ± 0.20 wt%, and the micelle stability in water was supported by low critical micelle concentration of 14.31 ± 0.21 μg/ml. The drug-loaded micelles presented a slow and incomplete in vitro release, and the pharmacokinetic studies indicated the micelle carriers increased the relative bioavailability of PTX to 165.8% against the commercial formulation. The enhancement effect on intestinal absorption was also confirmed by the intracellular uptake of Caco-2 cells. The proposed micelle carrier system manifested a prospective tool for oral drug delivery.

Synthesis, Colloidal Characterization and Targetability of Phenylboronic Acid Functionalized α-Tocopheryl Polyethylene Glycol Succinate in Cancer Cells

This study reports targetable micelles developed after covalent functionalization of α-tocopheryl polyethylene glycol succinate (TPGS) with amino phenylboronic acid (APBA). Nuclear magnetic resonance (NMR) and infrared (IR) spectroscopic results showed successful attachment of APBA to the hydrophilic segment of TPGS. Dynamic light scattering and small-angle neutron scattering studies revealed that the conjugate self-assembled in water to produce spherical core-shell micelles (14–20 nm) which remained stable against temperature (ca. 25–45 °C) and pH changes. The micelles could solubilize a high payload of paclitaxel (PLX) without exhibiting changes in the average size. However, at the saturation solubility, drug molecules migrated from the core to the shell region and engaged with APBA groups via π–π stacking interaction. Confocal microscopy and cell sorting analyses verified the effective translocation ability of TPGS-APBA micelles in sialic acid (SA) expressing MDA-MB-453 cells. At equivalent PLX dose, TPGS-APBA micelles showed about a twofold improvement in apoptotic death among the cells exposed for 2 h. Our findings indicate that the attachment of APBA can be a potential strategy for improving the intra-cellular localization of carriers among cancer cells expressing SA residues.

Optimization of Docetaxel Loading Conditions in Liposomes: proposing potential products for metastatic breast carcinoma chemotherapy

Docetaxel (DTX) was loaded in nanoliposomes based on a new remote loading method using mannitol and acetic acid as hydration buffer. DTX loading conditions were optimized, and the final formulations were prepared according to the best parameters which were HSPC/mPEG2000-DSPE/Chol (F1), HSPC/mPEG2000-DSPE/DPPG/Chol (F2), HSPC/mPEG2000-DSPE/DSPG/Chol (F3), at molar ratios of 85/5/10, 80/5/5/10, 80/5/5/10, respectively. DTX-liposomes were found of desired size (~115 nm) and homogeneity (PDI ≤ 0.2), high drug encapsulation efficacy (34-67%) and DTX concentration, and favorable stability. Passive loaded counterparts liposomes showed three times lower encapsulation efficacy compared to the remote loaded liposomes. The drug release of remote loaded liposomes in plasma 50% was significantly more controlled and less in comparison with their passive loaded counterparts (p < 0.0001). The IC50 values of formulations were determined on MCF-7, 4T1, TUBO, NIH/3T3 cell lines. The biodistribution of iodinated docetaxel as free or liposomal form exhibited significantly greater accumulation of DTX-liposomes in tumors than that of free docetaxel due to the EPR effect. In vivo experiment with BALB/c mice bearing 4T1 or TUBO breast carcinoma tumors also showed that DTX-liposomes could significantly delay tumor growth and prolonged the survival time in comparison with control and Taxotere groups at the similar dose of 8 mg/kg. F1 and F2 formulations were stable and showed good anti-tumor activity and merit further investigation.

Docetaxel-loaded D-α-tocopheryl polyethylene glycol-1000 succinate liposomes improve lung cancer chemotherapy and reverse multidrug resistance

In this study, D-alpha-tocopheryl polyethylene glycol-1000 succinate (TPGS)-coated docetaxel-loaded liposomes were developed to reverse multidrug resistance (MDR) and enhance lung cancer therapy. Evaluations were performed using human lung cancer A549 and resistant A549/DDP cells. The reversal multidrug resistant effect was assessed by P-gp inhibition assay, cytotoxicity, cellular uptake, and apoptosis assay. The tumor xenograft model was built by subcutaneous injection of A549/DDP cells in the right dorsal area of nude mice. The tumor volumes and body weights were measured every other day. The TPGS-coated liposomes showed a concentration- and time-dependent cytotoxicity and significantly enhanced the cytotoxicity of docetaxel in A549/DDP cells. Confocal laser scanning images indicated that higher concentrations of coumarin-6 were successfully delivered into the cytoplasm, and the TPGS-coated liposomes enhanced intracellular drug accumulation by inhibiting overexpressed P-glycoprotein. The TPGS-coated liposomes were shown to induce apoptosis. Furthermore, in vivo anti-tumor studies revealed that TPGS-coated docetaxel-loaded liposomes had outstanding anti-tumor efficacy in an A549/DDP xenograft model. The TPGS-coated liposomes, compared with PEG-coated liposomes, showed significant advantages in vitro and in vivo. The TPGS-coated liposomes were able to reverse MDR and enhance lung cancer therapy. Graphical abstract .

Solubility and Bioavailability Enhancement of Oridonin: A Review

Oridonin (ORI), an ent-kaurene tetracyclic diterpenoid compound, is isolated from Chinese herb Rabdosia rubescens with various biological and pharmacological activities including anti-tumor, anti-microbial and anti-inflammatory effects. However, the clinical application of ORI is limited due to its low solubility and poor bioavailability. In order to overcome these shortcomings, many strategies have been explored such as structural modification, new dosage form, etc. This review provides a detailed discussion on the research progress to increase the solubility and bioavailability of ORI.

Improved chemotherapeutic efficacy against resistant human breast cancer cells with co-delivery of Docetaxel and Thymoquinone by Chitosan grafted lipid nanocapsules: Formulation optimization, in vitro and in vivo studies

In recent years, multi-targeted chemotherapeutic combinations have received considerable attention in solid tumor chemotherapy. Here, we optimized low-molecular-weight chitosan (CS)-grafted lipid nanocapsules (LNCs, referred to as CLNCs) for the co-delivery of docetaxel (DTX) and thymoquinone (THQ) to treat drug-resistant breast cancer. We first screened size reduction techniques (homogenization vs ultrasonication), and then the 3³-Box-Behnken design was employed to determine optimal conditions of the final LNCs with the desired quality attributes. Uncoated LNCs had a particle size of 141.7 ± 2.8 nm (Polydispersity index, PdI: 0.17 ± 0.02) with entrapment efficiency (%EE) of 66.1 ± 3.5 % and 85.3 ± 3.1 % for DTX and THQ, respectively. The CS functionalization of LNCs improved the uptake and endosomal escape effect, and led to a significantly higher cytotoxicity against MCF-7 and triple-negative (MDA-MB-231) breast cancer cells. Furthermore, an enhanced antiangiogenic effect was observed with DTX- and THQ-carrying CLNCs in the Chick embryo chorioallantoic membrane (CAM) assay.

Nanotargeted agents: an emerging therapeutic strategy for breast cancer

Breast cancer is the most common female cancer worldwide and represents 12% of all cancer cases. Improvements in survival rates are largely attributed to improved screening and diagnosis. Conventional chemotherapy remains an important treatment option but it is beset with poor cell selectivity, serious side effects and resistance. Nanoparticle drug delivery systems bring promising opportunities to breast cancer treatment. They may improve chemotherapy by targeting drugs to tumors, generating high drug concentrations at tumors providing slow release of the drug, increased drug stability and concomitant reductions in side effects. The nanotechnology-based drug delivery approaches and the current research and application status of nano-targeted agents for breast cancer are discussed in this review to provide a basis for further study on targeted drug delivery systems.

Vitamin E D-alpha-tocopheryl polyethylene glycol 1000 succinate-conjugated liposomal docetaxel reverses multidrug resistance in breast cancer cells

Objectives

Multidrug resistance (MDR) remains a primary challenge in breast cancer treatment. In the present study, D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS)-coated docetaxel-loaded liposomes were developed as a novel drug delivery system to reverse MDR and enhance breast cancer therapy compared with the traditional liposomes, DSPE-mPEG-coated liposomes (stealth liposomes) and commercial Taxotere®.

Key findings

Liposomes were prepared by thin – film dispersion method. Evaluations were performed using human breast cancer MCF-7 and resistant MCF-7/ADR cells. The reversal multidrug-resistant effect was assessed by P-gp inhibition assay, cytotoxicity, cellular uptake and apoptosis assay.

Results

The TPGS-chol-liposomes were of an appropriate particle size (140.0 ± 6.0 nm), zeta potential (−0.196 ± 0.08 mv), high encapsulation efficiency (99.0 ± 0.9) and favourable in vitro sustained release. The TPGS-coated liposomes significantly improved cytotoxicity and increased the intracellular accumulation of docetaxel in both types of breast cancer cells. The TPGS-coated liposomes were confirmed to induce apoptosis via a synergistic effect between docetaxel and TPGS. It was demonstrated that TPGS enhanced the intracellular accumulation of drug by inhibiting overexpressed P-glycoprotein.

Conclusions

The TPGS-conjugated liposomes showed significant advantages in vitro compared with the PEG-conjugated liposomes. The TPGS-conjugated liposomes could reverse the MDR and enhance breast cancer therapy.

TPGS-grafted and acid-responsive soy protein nanogels for efficient intracellular drug release, accumulation, penetration in 3D tumor spheroids of drug-resistant cancer cells

The frequent occurrence of multidrug resistance (MDR) in solid tumors is the major obstacle for nano-drug delivery systems (nDDS) to realize the successful cancer chemotherapy. Herein, we had prepared pH-responsive nanogels via cross-linking TPGS-grafted soy protein with an acid-labile ortho ester cross-linker (OEAM) to realize the efficient intracellular drugs release and accumulation, and subsequently enhance therapeutic effect in MDR tumor cells. These nanogels displayed a uniform size (~200 nm) and morphology, and the introduction of ortho ester bonds endowed nanogels stability in neutral environment and acid-degradability in acidic conditions. Cisplatin (CDDP) was successfully loaded into nanogels, which exhibited an accelerated drug release at low pH. The modification of TPGS efficiently improved cellular internalization and drug accumulation in A549/DDP cells by inhibiting the function of drug efflux pumps (MRP2 and ATP7A/7B), leading to higher cytotoxicity and apoptosis. Moreover, TPGS-grafted nanogels also showed better drug accumulation and penetration in tumor-like spheroids, and then remarkably inhibited tumor growth owing to the rapid drug release in acidic organelles. As a result, the TPGS-grafted and pH-sensitive soy protein nanogels have a great potential as a drugs carrier for the efficient cancer treatment.

Evaluation of Anti-Tumor Efficacy of Vorinostat Encapsulated Self-Assembled Polymeric Micelles in Solid Tumors

Vorinostat (VOR), a potent HDAC inhibitor, suffers from low solubility and poor absorption, which hinders its successful application in therapy, especially in the treatment of solid tumors. In this study, an effort to improve the physicochemical characteristics of VOR was made by encapsulating it in PEG-PLGA copolymeric micelles. VOR-loaded PEG-PLGA micelles (VOR-PEG-PLGA) were produced by thin-film hydration and physicochemically characterized. The PEG-PLGA micelles had an average size of 124.06 ± 2.6 nm, polydispersity index of 0.27 ± 0.1, and entrapment efficiency of 90 ± 2.1%. Micelles were characterized by TEM, DSC, and drug release studies. The drug release occurred in a sustained manner up to 72 h from PEG-PLGA micelles. In the in vitro cell-based studies using human breast cancer (MDA MB 231) and murine melanoma (B16F10) cell lines, VOR-PEG-PLGA micelles exhibited superior cellular internalization, enhanced cytotoxic activity, and greater apoptosis compared to free drug. Percent cell killing of 54.9% for VOR-PEG-PLGA-treated cells was observed after 24 h compared to 36% for free VOR in MDA MB 231 cell line. Further, significant tumor suppression was witnessed in B16F10 tumor-bearing mice treated with VOR-PEG-PLGA micelles with a 1.78-fold reduction in tumor volume compared to free VOR-treated animals. Overall, the VOR-PEG-PLGA micelles improved the biopharmaceutical properties of VOR, which resulted in enhanced anti-tumor efficacy. Therefore, the newly developed nano-formulation of VOR could be considered as an effective treatment option in solid tumors.

Mixed micelles for encapsulation of doxorubicin with enhanced in vitro cytotoxicity on breast and ovarian cancer cell lines versus Doxil®

Doxorubicin (DOX) is used as a "first-line" antineoplastic drug in ovarian and metastatic breast cancer. However, serious side effects, such as cardiotoxicity have been reported after DOX intravenous administration. Hence, we investigated different micelle-former biomaterials, as Soluplus^®, Pluronic F127, Tetronic T1107 and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) to develop a potential mixed micellar nanocarrier for DOX delivery. Since DOX hydrochloride is a poor candidate to be encapsulated inside the hydrophobic core of the mixed micelles, we assayed a hydrophobic complex between DOX and sodium deoxycholate (NaDC) as an excellent candidate to be encapsulated within polymeric micelles. The combination of T1107:TPGS (1:3, weight ratio) demonstrated the best physicochemical properties together with a high DL capacity (6.43% w/v). Particularly, DOX in vitro release was higher at acidic tumour microenvironment pH value (5.5) than at physiological counterpart (7.4). The hydrodynamic diameter of the DOX/NaDC-loaded mixed micellar system was 10.7nm (PDI=0.239). The in vitro cytotoxicity of the mixed micellar formulation resulted significantly (p<0.05) higher than Doxil^® against ovarian (SKOV-3) and triple-negative breast cancer cells (MDA-MB- 231). Further, the in vitro cellular uptake assays demonstrated a significant increment (p<0.05) of the DOX intracellular content for the mixed micelles versus Doxil^® for both, SKOV-3 (at 2, 4 and 6h of incubation) and MDA-MB-231 (at 4h of incubation) cells. These findings suggest that T1107:TPGS (1:3) mixed micelles could be employed as a potential nanotechnological platform for drug delivery of DOX.

Precise ratiometric loading of PTX and DOX based on redox-sensitive mixed micelles for cancer therapy

PTX and DOX have different anticancer mechanisms. The combination of the two anticancer drugs could synergically enhance their anticancer effect, but simultaneously accompanied by severe side effects. In the present study, we constructed a mixed micelle system based on redox-sensitive mPEG-SS-PTX and mPEG-SS-DOX conjugate. The drug delivery system has a fixed and high drug loading content of 24.2% (PTX∼14.8% and DOX∼9.4%) with a precise ratio of PTX and DOX to realize the synchronized and controlled release. The mixed micelle has an average size of 93.3nm with a narrow distribution, suitable for passive targeting to tumor tissues by the EPR effect. In vitro release profile and in vitro anticancer results show the mixed micelles have obvious redox-sensitive release properties in reducing environment and have a significant cytotoxicity to A549 and B16 cells. Importantly, in vivo study shows the mixed micelles have no obvious side effect on mice compared to free PTX/DOX samples during the treatment. Therefore, the constructed redox-sensitive mixed micelle is a promising drug delivery system for cancer therapy.

Photothermal gold nanocages filled with temperature sensitive tetradecanol and encapsulated with glutathione responsive polycurcumin for controlled DOX delivery to maximize anti-MDR tumor effects

AuNCs@DBPP were taken up by MCF-7/ADR cells through biotin receptor mediated endocytosis and triggered to release DOX under NIR irradiation.

Lipid–polymer hybrid nanoparticles for synergistic drug delivery to overcome cancer drug resistance

Co-delivery of a chemotherapeutic drug and a drug resistance inhibitor by lipid–polymer hybrid nanoparticles can effectively overcome tumor drug resistance.

In Vivo Bio-distribution and Efficient Tumor Targeting of Gelatin/Silica Nanoparticles for Gene Delivery

The non-viral gene delivery system is an attractive alternative to cancer therapy. The clinical success of non-viral gene delivery is hampered by transfection efficiency and tumor targeting, which can be individually overcome by addition of functional modules such as cell penetration or targeting. Here, we first engineered the multifunctional gelatin/silica (GS) nanovectors with separately controllable modules, including tumor-targeting aptamer AGRO100, membrane-destabilizing peptide HA2, and polyethylene glycol (PEG), and then studied their bio-distribution and in vivo transfection efficiencies by contrast resonance imaging (CRI). The results suggest that the sizes and zeta potentials of multifunctional gelatin/silica nanovectors were 203-217 nm and 2-8 mV, respectively. Functional GS-PEG nanoparticles mainly accumulated in the liver and tumor, with the lowest uptake by the heart and brain. Moreover, the synergistic effects of tumor-targeting aptamer AGRO100 and fusogenic peptide HA2 promoted the efficient cellular internalization in the tumor site. More importantly, the combined use of AGRO100 and PEG enhanced tumor gene expression specificity and effectively reduced toxicity in reticuloendothelial system (RES) organs after intravenous injection. Additionally, low accumulation of GS-PEG was observed in the heart tissues with high gene expression levels, which could provide opportunities for non-invasive gene therapy.

Polymeric micelles of suberoylanilide hydroxamic acid to enhance the anticancer potential in vitro and in vivo

AIM

To improve the bioavailability and anticancer potential of suberoylanilide hydroxamic acid (SAHA) by developing a drug-loaded polymeric nanomicellar system.

METHODS

SAHA-loaded Poly(ethylene glycol)-block-poly(caprolactone) (PEG-PCL) micelles were developed, and physico-chemically characterized. In vitro cellular uptake, viability and apoptosis-inducing ability of the SAHA-PEG-PCL micelles were investigated. In vivo anticancer activity was evaluated in C57BL/6 mice-bearing tumor.

RESULTS

The SAHA-PEG-PCL micelles had optimum size (∼130 nm) with an entrapment efficiency of approximately 67%. The SAHA-PEG-PCL induced stronger cell cycle arrest in G2/M phase leading to higher rate of apoptosis compared to free SAHA. SAHA-PEG-PCL demonstrated significant tumor suppression compared to free SAHA in vivo.

CONCLUSION

The physicochemical properties and the antitumor efficacy of SAHA were improved by encapsulating in polymeric micelles.

Radiolabeling and biological characterization of TPGS-based nanomicelles by means of small animal imaging

INTRODUCTION

In recent years, nanomedicines have raised as a powerful tool to improve prevention, diagnosis and treatment of different pathologies. Among the most well investigated biomaterials, D-α-tocopheryl polyethylene glycol succinate (also known as TPGS) has been on the spot for the last decade. We therefore designed a method to biologically characterize TPGS-based nanomicelles by labeling them with ^99mTc.

METHODS

Labeling process was performed by a direct method. The average hydrodynamic diameter of TPGS nanomicelles was measured by dynamic light scattering and radiochemical purity was assessed by thin layer chromatography. Imaging: a dynamic study was performed during the first hour post radioactive micelles administration in a gamma camera (TcO₄^- was also administered for comparative purposes). Then two static images were acquired in ventral position: 1h and 12h post injection. Blood pharmacokinetics of ^99mTc-TPGS during 24h was performed.

RESULTS

Images revealed whole body biodistribution at an early and delayed time and semiquantification was performed in organs of interest (%Total counts: soft tissue 6.1±0.5; 3.9±0.1, Bone 1.2±0.2; 1±0.1, Heart 1.5±0.6; 0.7±0.3, Kidneys 16.6±1.3; 26.5±1.7, Liver 8.6±1.1; 11.1±0.1 for 1 and 12 h post injection respectively).

CONCLUSION

This work demonstrated that TPGS based nanomicelles are susceptible to be radiolabeled with ^99mTc thus they can be used to perform imaging studies in animal models. Moreover radiolabeling of these delivery nano systems reveals their possibility to be used as diagnostic agents in the near future.

Co-delivery of docetaxel and chloroquine via PEO-PPO-PCL/TPGS micelles for overcoming multidrug resistance

The combination of two or more drug is a promising strategy to suppress the multidrug resistance (MDR) through different action mechanisms. Co-delivery drugs via polymeric micelle can minimize the amount of each drug and reduce toxic side effects. Here we co-encapsulate anticancer drug docetaxel (DTX) and autophagy inhibitor chloroquine (CQ) in complex micelles based on poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ϵ-caprolactone) (PEO-PPO-PCL) and D-α-tocopheryl poly(ethylene glycol) (TPGS) for enhancing anticancer effects. Two series copolymer with different length of hydrophobic chain were synthesized (PEO68-PPO34-PCL18 and PEO68-PPO34-PCL36) in our lab. The dual-drug micelles possessed nanosize and sustained release profile in vitro. Drug-loaded micelles have low hemolysis rate (<5%), indicating that they are safe for use in vivo. Studies on cellular uptake demonstrate that the micelles can effectively accumulate in cancer cells. Furthermore, in vitro cytotoxicity with different DTX/CQ mass ratio are studied and the sample with a DTX/CQ ratio of 0.8/0.2 is found to have the strongest synergism effect. The co-delivery micelles have obviously higher therapeutic effects against MCF-7 and MCF-7/ADR cells than either free drug or individually DTX-loaded micelles. The IC50 values of DTX/CQ-loaded PEO68-PPO34-PCL18/TPGS and PEO68-PPO34-PCL36/TPGS micelles are 134.16 and 194.74 fold smaller than that of free DTX after 48 h treatment with MCF-7/ADR cells, respectively. Therefore, the as-prepared co-delivery of DTX and CQ based on PEO-PPO-PCL/TPGS micelles can provide a promising combined therapeutic strategy for enhanced antitumor therapy.