Star-shape copolymer of lysine-linked di-tocopherol polyethylene glycol 2000 succinate for doxorubicin delivery with reversal of multidrug resistance

Discerning computational, in vitro and in vivo investigations of self-assembling empagliflozin polymeric micelles in type-2 diabetes

BACKGROUND

Empagliflozin (EMPA) is an SGLT2 inhibitor, a new class of anti-diabetic medication, indicated for treating type-2 diabetes. Its low permeability, poor solubility and bioavailability limits its use in management of diabetes. The study was aimed to formulate EMPA loaded polymeric micelles (PMs) to overcome these obstacles in oral absorption.

METHODOLOGY

In silico studies-molecular docking, molecular dynamic simulation (MDS), and quantum chemical calculation were employed to study the interaction of EMPA with different polymers. EMPA loaded TPGS polymeric micelles (EMPA-TPGS-PMs) were formulated by direct dissolution method and characterized in terms of surface morphology, entrapment, particle size, in vitro drug release, and in vitro cytotoxicity (HEK293 cells). In vivo pharmacokinetic and pharmacodynamic studies were also performed.

RESULTS

The results suggested a good interaction between TPGS and EMPA with lowest binding energy compared to other polymers. Further MDS results and DFT calculations validated the stable binding of the complex hence TPGS was selected for further wet lab experiments. The EMPA-TPGS complex displayed lower value of Total energy (T.E.) than its individual components, indicating the overall stability of the complex while, the energy band gap (∆E) value lied between the two individual molecules, signifying the better electron transfer between HOMO and LUMO of the complex. Based on the solubility, entrapment and cytotoxicity studies, 5% TPGS was selected for formulating drug loaded micelles. EMPA-TPGS5-PMs presented a size of 9.008 ± 1.25 nm, Polydispersity index (PDI) of 0.254 ± 0.100, a controlled release behaviour upto 24 h. SEM and AFM images of the nanoformulation suggested spherical particles whereas, DSC, and PXRD studies confirmed the loss of crystallinity of EMPA. A 3.12-folds higher AUC and a greater reduction in blood glucose levels was exhibited by EMPA-TPGS5-PMs in comparison to EMPA-SUSP in mice model.

CONCLUSION

EMPA-TPGS-PMs has exhibited better bio absorption and therapeutic effectiveness in diabetes treatment. This improved performance would open the possibility of dose reduction, reduced dosing frequency & dose-related side effects, improving pharmaco-economics and thereby improved overall compliance to the patient. However, this translation from bench to bedside would necessitate studies in higher animals and human volunteers.

Stage-specific treatment of colorectal cancer: A microRNA-nanocomposite approach

Colorectal cancer (CRC) is among the leading causes of cancer mortality. The lifetime risk of developing CRC is about 5% in adult males and females. CRC is usually diagnosed at an advanced stage, and at this point therapy has a limited impact on cure rates and long-term survival. Novel and/or improved CRC therapeutic options are needed. The involvement of microRNAs (miRNAs) in cancer development has been reported, and their regulation in many oncogenic pathways suggests their potent tumor suppressor action. Although miRNAs provide a promising therapeutic approach for cancer, challenges such as biodegradation, specificity, stability and toxicity, impede their progression into clinical trials. Nanotechnology strategies offer diverse advantages for the use of miRNAs for CRC-targeted delivery and therapy. The merits of using nanocarriers for targeted delivery of miRNA-formulations are presented herein to highlight the role they can play in miRNA-based CRC therapy by targeting different stages of the disease.

Construction of multi-program responsive vitamin E succinate-chitosan-histidine nanocarrier and its response strategy in tumor therapy

Multifunctional drug delivery carriers have emerged as a promising cancer drug delivery strategy. Here, we developed a vitamin E succinate-chitosan-histidine (VCH) multi-program responsive drug carrier. The structure was characterized by FT-IR and 1H NMR spectrum, and the DLS and SEM results showed typical nanostructures. The drug loading content was 21.0 % and the corresponding encapsulation efficiency was 66.6 %. The UV-vis and fluorescence spectra demonstrated the existence of the π-π stacking interaction between DOX and VCH. Drug release experiments implied good pH sensitivity and sustained-release effect. The DOX/VCH nanoparticles could be efficiently taken up by HepG2 cancer cells and the tumor inhibition rate was up to 56.27 %. The DOX/VCH reduced the tumor volume and weight efficiently with a TIR of 45.81 %. The histological analysis results showed that DOX/VCH could effectively inhibit tumor growth and proliferation, and there was no damage to normal organs. VCH nanocarriers could combine the advantages of VES, histidine and chitosan to achieve pH sensitivity and P-gp inhibition, and effectively improve the drug solubility, targeting and lysosomal escape. Through the program response of different micro-environment, the newly developed polymeric micelles could successfully be utilized as a multi-program responsive nanocarrier system for the treatment of cancers.

Recent Advances in Doxorubicin Formulation to Enhance Pharmacokinetics and Tumor Targeting

Doxorubicin (DOX), a widely used drug in cancer chemotherapy, induces cell death via multiple intracellular interactions, generating reactive oxygen species and DNA-adducted configurations that induce apoptosis, topoisomerase II inhibition, and histone eviction. Despite its wide therapeutic efficacy in solid tumors, DOX often induces drug resistance and cardiotoxicity. It shows limited intestinal absorption because of low paracellular permeability and P-glycoprotein (P-gp)-mediated efflux. We reviewed various parenteral DOX formulations, such as liposomes, polymeric micelles, polymeric nanoparticles, and polymer-drug conjugates, under clinical use or trials to increase its therapeutic efficacy. To improve the bioavailability of DOX in intravenous and oral cancer treatment, studies have proposed a pH- or redox-sensitive and receptor-targeted system for overcoming DOX resistance and increasing therapeutic efficacy without causing DOX-induced toxicity. Multifunctional formulations of DOX with mucoadhesiveness and increased intestinal permeability through tight-junction modulation and P-gp inhibition have also been used as orally bioavailable DOX in the preclinical stage. The increasing trends of developing oral formulations from intravenous formulations, the application of mucoadhesive technology, permeation-enhancing technology, and pharmacokinetic modulation with functional excipients might facilitate the further development of oral DOX.

Size-adjustable self-assembled nanoparticles through microfluidic platform promotes neuronal differentiation of mouse embryonic stem cells

Neuronal differentiation from stem cells is one of the most potent therapeutic approaches for recovering neurological function in individuals with neurodegenerative disorders. Herein, an on-demand intracellular retinoic acid released nanoparticles with tunable size and accurately controlled physico-biological properties have been prepared for achieving efficient neuronal differentiation. The amphiphilic chitosan oligosaccharide-cholesterol copolymers were synthesized by varying cholesterol content and self-assembled into spherical micelle in a microfluidic chip with different flow rates. Notably, the results indicated that by increasing the lipophilicity of the chitosan chain as well as mixing rate, the size of micelles was decreased. Retinoic acid (RA) was efficiently encapsulated in the core of micelles. The retinoic acid-containing nanoparticles could escape lysosome, accumulate in the cytoplasm, and release payload with a sustained pattern. The cytotoxicity assay of free retinoic acid and retinoic acid-loaded formulations against P19 embryonic stem cells confirmed the desirable safety of micelles. The result obtained from the uptake study showed that internalization of micelles occurs predominantly via lipid-raft endocytosis in the presence of higher cholesterol content. Moreover, the intracellular RA release upregulated the expression levels of neuronal factors. The micelles described here offer a promising nanomedicine strategy for neuronal differentiation of stem cells.

Reactive Oxygen Species-Responsive Miktoarm Amphiphile for Triggered Intracellular Release of Anti-Cancer Therapeutics

Reactive oxygen species (ROS)-responsive nanocarriers have received considerable research attention as putative cancer treatments because their tumor cell targets have high ROS levels. Here, we synthesized a miktoarm amphiphile of dithioketal-linked ditocopheryl polyethylene glycol (DTTP) by introducing ROS-cleavable thioketal groups as linkers between the hydrophilic and hydrophobic moieties. We used the product as a carrier for the controlled release of doxorubicin (DOX). DTTP has a critical micelle concentration (CMC) as low as 1.55 μg/mL (4.18 × 10⁻⁴ mM), encapsulation efficiency as high as 43.6 ± 0.23% and 14.6 nm particle size. The DTTP micelles were very responsive to ROS and released their DOX loads in a controlled manner. The tocopheryl derivates linked to DTTP generated ROS and added to the intracellular ROS in MCF-7 cancer cells but not in HEK-293 normal cells. In vitro cytotoxicity assays demonstrated that DOX-encapsulated DTTP micelles displayed strong antitumor activity but only slightly increased apoptosis in normal cells. This ROS-triggered, self-accelerating drug release device has high therapeutic efficacy and could be a practical new strategy for the clinical application of ROS-responsive drug delivery systems.

Micelles Based on Lysine, Histidine, or Arginine: Designing Structures for Enhanced Drug Delivery

Natural amino acids and their derivatives are excellent building blocks of polymers for various biomedical applications owing to the non-toxicity, biocompatibility, and ease of multifunctionalization. In the present review, we summarized the common approaches to designing and constructing functional polymeric micelles based on basic amino acids including lysine, histidine, and arginine and highlighted their applications as drug carriers for cancer therapy. Different polypeptide architectures including linear polypeptides and dendrimers were developed for efficient drug loading and delivery. Besides, polylysine- and polyhistidine-based micelles could enable pH-responsive drug release, and polyarginine can realize enhanced membrane penetration and gas therapy by generating metabolites of nitric oxide (NO). It is worth mentioning that according to the structural or functional characteristics of basic amino acids and their derivatives, key points for designing functional micelles with excellent drug delivery efficiency are importantly elaborated in order to pave the way for exploring micelles based on basic amino acids.

Cyclodextrin Polymers as Delivery Systems for Targeted Anti-Cancer Chemotherapy

In the few last years, nanosystems have emerged as a potential therapeutic approach to improve the efficacy and selectivity of many drugs. Cyclodextrins (CyDs) and their nanoparticles have been widely investigated as drug delivery systems. The covalent functionalization of CyD polymer nanoparticles with targeting molecules can improve the therapeutic potential of this family of nanosystems. In this study, we investigated cross-linked γ- and β-cyclodextrin polymers as carriers for doxorubicin (ox) and oxaliplatin (Oxa). We also functionalized γ-CyD polymer bearing COOH functionalities with arginine-glycine-aspartic or arginine moieties for targeting the integrin receptors of cancer cells. We tested the Dox and Oxa anti-proliferative activity in the presence of the precursor polymer with COOH functionalities and its derivatives in A549 (lung, carcinoma) and HepG2 (liver, carcinoma) cell lines. We found that CyD polymers can significantly improve the antiproliferative activity of Dox in HepG2 cell lines only, whereas the cytotoxic activity of Oxa resulted as enhanced in both cell lines. The peptide or amino acid functionalized CyD polymers, loaded with Dox, did not show any additional effect compared to the precursor polymer. Finally, studies of Dox uptake showed that the higher antiproliferative activity of complexes correlates with the higher accumulation of Dox inside the cells. The results show that CyD polymers could be used as carriers for repositioning classical anticancer drugs such as Dox or Oxa to increase their antitumor activity.

Impact of Poly (Styrene-Acrylic Acid) Latex Nanoparticles on Colorectal and Cervical Cancer Cells

Polymer nanoparticles are a promising approach for cancer treatment and detection, due to their biocompatibility, biodegradability, targeting capabilities, capacity for drug loading and long blood circulation time. This study aims to evaluate the impact of poly (styrene–acrylic acid) latex particles on colorectal and cervical cancer cells for anti-tumor efficiency. Latex particles were synthesized by a surfactant-free radical emulsion polymerization process and the obtained polymer particles were characterized in terms of size, size distribution, morphology using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and electrokinetic property (i.e., zeta potential). Human colorectal and cervical cancer, and normal cell lines, were then treated with different concentrations of poly (styrene–acrylic acid) latex particles. The cell morphology changes were pointed out using an optical microscope and the nanoparticles’ (NPs) cell cytotoxicity was evaluated using MTT assay. The obtained results showed that poly (styrene–acrylic acid) latex particles are effective against colorectal and cervical cancer cells if treated with an appropriate particle concentration for 48 h. In addition, it showed that normal cells are the least affected by this treatment. This indicates that these NPs are safe as a drug delivery carrier when used at a low concentration.

Characterization of Cepharanthin Nanosuspensions and Evaluation of Their In Vitro Activity for the HepG2 Hepatocellular Carcinoma Cell Line

BACKGROUND

Conventional cancer therapeutics has enormous toxicity and severe side effects that generate multi-drug resistance. Therefore, an urgent need exists for new alternative therapeutic agents for cancer treatment. Cepharanthin (CEP) has anti-cancer potential but has poor aqueous solubility, which limits its clinical use. Nanosuspensions (NS) are attractive as insoluble drug delivery systems.

OBJECTIVES

In this study, we used D-alpha Tocopherol acid Polyethylene Glycol Succinate (TPGS), Polyvinylpyrrolidone (PVP) VA64, and Croscamellose Sodium (CCS) as stabilizers to produce TPGS-CEP-NS, PVP VA64-CEP-NS, and CCS-CEP-NS by wet-milling technology, and then characterized the NS and evaluated their functional activities in vitro.

METHODS

CEP Nanosuspensions (CEP-NS) were prepared by the wet-milling method. The prepared NS were characterized by particle size distribution, zeta potential, morphology, surface properties, and molecular interactions. The NS were evaluated for their effects on HepG2 cells in vitro. The evaluations included assessment of cellular cytotoxicity, cellular apoptosis, NS uptake by cells, and mitochondrial membrane potential changes.

RESULTS

CEP-NS showed an appropriate particle size and were physically stable. All CEP-NS exhibited HepG2 enhanced anti-proliferative effects by reducing cell viability, enhanced cellular uptake, induced cellular apoptosis, and mitochondrial membrane potential loss.

CONCLUSIONS

CEP-NS may be effective therapeutic agents for the treatment of hepatocellular carcinoma.

Recent progress in nanoformulations of cabazitaxel

The antitumor efficacy of various paclitaxel (PTX) and docetaxel (DTX) formulations in clinical applications is seriously affected by drug resistance. Cabazitaxel, a second-generation taxane, exhibits greater anticancer activity than paclitaxel and docetaxel and has low affinity for the P-glycoprotein (P-gp) efflux pump because of its structure. Therefore, cabazitaxel has the potential to overcome taxane resistance. However, owing to the high systemic toxicity and hydrophobicity of cabazitaxel and the instability of its commercial preparation, Jevtana®, the clinical use of cabazitaxel is restricted to patients with metastatic castration-resistant prostate cancer (mCRPC) who show progression after docetaxel-based chemotherapy. Nanomedicine is expected to overcome the limitations associated with cabazitaxel application and surmount taxane resistance. This review outlines the drug delivery systems of cabazitaxel published in recent years, summarizes the challenges faced in the development of cabazitaxel nanoformulations, and proposes strategies to overcome these challenges.

Formulation and Evaluation of Atorvastatin Calcium-Poly-ε-Caprolactone Nanoparticles Loaded Ocular Inserts for Sustained Release and Antiinflammatory Efficacy

PURPOSE

The work was performed to investigate the feasibility of preparing ocular inserts loaded with Poly-ε-Caprolactone (PCL) nanoparticles as a sustained ocular delivery system.

METHODS

First, Atorvastatin Calcium-Poly-ε-Caprolactone (ATC-PCL) nanoparticles were prepared and characterized. Then, the optimized nanoparticles were loaded within inserts formulated with Methylcellulose (MC) and Polyvinyl Alcohol (PVA) by a solvent casting technique and evaluated physically, for in-vitro drug release profile. Finally, an in-vivo study was performed on the selected formulation to prove non-irritability and sustained ocular anti-inflammatory efficacy compared with free drug-loaded ocuserts.

RESULTS

The results revealed (ATC-PCL) nanoparticles prepared with 0.5% pluronic F127 were optimized with 181.72±3.6 nm particle size, 0.12±0.02 (PDI) analysis, -27.4± 0.69 mV zeta potential and 62.41%±4.7% entrapment efficiency. Nanoparticles loaded ocuserts manifested compatibility between drug and formulation polymers. Moreover, formulations complied with average weight 0.055±0.002 to 0.143±0.023 mg, and accepted pH. ATC-PCL nanoparticles loaded inserts prepared by 5% MC showed more sustained, prolonged in-vitro release over 24h. In-vivo study emphasized non-irritability, ocular anti-inflammatory effectiveness represented by smaller lid closure scores, and statistically significant lowering in PMN count after 3h.

CONCLUSION

These findings proposed a possibly simple, new and affordable price technique to prepare promising (ATC-PCL) nanoparticles loaded inserts to achieve sustained release with prolonged antiinflammatory efficacy.

LDH-doped electrospun short fibers enable dual drug loading and multistage release for chemotherapy of drug-resistant cancer cells

LDH-incorporated PLGA short nanofibers can be loaded with dual drugs for multistage release and chemotherapy of drug-resistant cancer cells.

Zwitterionic Polymer Micelles with Dual Conjugation of Doxorubicin and Curcumin: Synergistically Enhanced Efficacy against Multidrug-Resistant Tumor Cells

This paper reports a novel redox-sensitive micellar system for the co-delivery of doxorubicin (Dox) and a chemosensitizer (curcumin, Cur) to overcome the multidrug resistance (MDR) in cancer cells. Dox and Cur were co-conjugated onto a zwitterionic polymer, poly(carboxybetaine) (pCB), to form Cur-pCB-Dox that self-assembled into stable micelles (164.2 ± 4.8 nm). Single-drug conjugates (pCB-Dox and pCB-Cur) were prepared for comparisons. Compared to the high half-maximal inhibitory concentration (IC₅₀) of Dox (437.2 μg/mL), the IC₅₀ value of pCB-Dox (14.1 μg/mL) was only 1/33 that of Dox. Confocal laser scanning microscopy and flow cytometry revealed the greatly enhanced cell uptake of the conjugate due to the enhanced permeability and retention effect of tumor cells on the micellar conjugate. Co-delivery of pCB-Dox with pCB-Cur further reduced the IC₅₀ value by 37% (8.9 μg/mL). More importantly, Cur-pCB-Dox exhibited the strongest cytotoxicity against MCF-7/Adr cells (IC₅₀, 5.87 μg/mL) because the co-delivered Dox and Cur on one carrier specifically transported into the same cells, which inhibited the efflux of Dox by Cur, led to a higher intracellular Dox concentration and made the drugs exert synergistic effects at the targeting regions. The results proved the zwitterionic micelles as promising drug co-delivery vehicles for fighting against MDR.

PEG-Derivatized Dual-Functional Nanomicelles for Improved Cancer Therapy

Polymeric micelles have attracted considerable attention for effective delivery of poorly water-soluble cancer drugs. Polyethylene glycol (PEG), which has been approved for human use by the US Food and Drug Administration, is the most commonly used hydrophilic component of polymeric micelles because it is biocompatible and biodegradable. One disadvantage of traditional polymeric micelles is that they include a large amount of inert carrier materials, which do not contribute to therapeutic activity but increase cost and toxicity risk. A better alternative may be "dual-functional" micellar carriers, in which the hydrophobic carrier material (conjugated to PEG) has intrinsic therapeutic activity that complements, or even synergizes with, the antitumor activity of the drug cargo. This review summarizes recent progress in the development of PEG-derivatized dual-functional nanomicelles and surveys the evidence of their feasibility and promise for cancer therapy.

Temporally Controlled Photothermal/Photodynamic and Combined Therapy for Overcoming Multidrug Resistance of Cancer by Polydopamine Nanoclustered Micelles

Currently, the simple integration of multiple therapeutic agents within a single nanostructure for combating multidrug resistance (MDR) tumors yet remains a challenge. Herein, we report a photoresponsive nanocluster (NC) system prepared by installing polydopamine (PDA) nanoparticle clusters on the surface of d-α-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS) (a drug efflux inhibitor) micelles solubilized with IR780 (a photosensitizer) to achieve a combined chemotherapy (CT)/photothermal therapy (PTT)/photodynamic therapy (PDT) for drug-resistant breast cancer. Mediated by the fluorescence resonance energy transfer and radical scavenging properties of PDA, NC shows prominently quenched fluorescence emission (∼78%) and inhibited singlet oxygen generation (∼67%) upon exposure to near-infrared (NIR) light (808 nm, 0.5 W cm^-2), favoring a highly efficient PTT module. Meanwhile, the photothermal heat can also boost the release of doxorubicin hydrochloride whose intracellular accumulation can be greatly enhanced by TPGS. Interestingly, the first NIR irradiation and subsequent incubation (∼24 h) can induce the gradual relocation and disintegration of PDA nanoparticles, thereby leading to activated PDT therapy under the second irradiation. Upon the temporally controlled sequential application of PTT/PDT, the developed NC exhibited a great potential to treat MDR cancer both in vitro and in vivo. These findings suggest that complementary interactions among PTT/PDT/CT modalities can enhance the efficiency of the combined therapy for MDR tumor.

Cyclodextrin polymers decorated with RGD peptide as delivery systems for targeted anti-cancer chemotherapy

Polymeric cyclodextrin-based nanoparticles are currently undergoing clinical trials as nanotherapeutics. Using a non-covalent approach, we decorated two cross-linked cyclodextrin polymers of different molecular weights with an RGD peptide derivative to construct a novel carrier for the targeted delivery of doxorubicin. RGD is the binding sequence for the integrin receptor family that is highly expressed in tumour tissues. The assembled host-guest systems were investigated using NMR and DLS techniques. We found that, in comparison with free doxorubicin or the binary complex doxorubicin/cyclodextrin polymer, the RGD units decorating the cyclodextrin-based nanosystems improved the selectivity and cytotoxicity of the complexed doxorubicin towards cultured human tumour cell lines. Our results suggest that the nanocarriers under study may contribute to the development of new platforms for cancer therapy.

Apically targeted oral micelles exhibit highly efficient intestinal uptake and oral absorption

Introduction

Polymeric micelles (PMs) hold promise for improving solubility and oral absorption of poorly soluble drugs. Unfortunately, the oral absorption of PMs is also limited by intestinal epithelium. To improve the oral delivery efficiency of micelles, transporter-mediated micelles could enhance the transport efficiency across the epithelial barrier, and they have attracted more attention.

Methods

Peptide transporter 1 (PepT1)-mediated micelles (Val-PMs/Phe-PMs) were designed by grafting valine (or phenylalanine) onto the surface of curcumin (Cur)-loaded-D-α-tocopheryl polyethylene glycol 1000 succinate micelles (TP-PMs). The oral absorption mechanism and oral bioavailability were further investigated in vitro and in vivo.

Results

The cellular study showed that Val-PMs/Phe-PMs had a high PepT1 affinity, resulting in a higher drug uptake and transcellular transport than TP-PMs. In rats, Val-PMs/Phe-PMs exhibited higher intestinal accumulation in the apical side of the intestinal epithelium than TP-PMs, promoting drug diffusion across epithelial barrier. The oral bioavailability of Cur was significantly improved by Val-PMs/Phe-PMs, which was about 10.50- and 3.40-fold greater than that of Cur-Sol and TP-PMs, respectively.

Conclusion

PepT-1-mediated micelles, using PepT1 as a target on intestinal epithelium, have unique functions with intestine and prove promising for oral delivery of poorly water-soluble drugs.

pH-Sensitive Poly(β-amino ester)s Nanocarriers Facilitate the Inhibition of Drug Resistance in Breast Cancer Cells

Multidrug resistance (MDR) remains an unmet challenge in chemotherapy. Stimuli-responsive nanocarriers emerge as a promising tool to overcome MDR. Herein, pH-sensitive poly(β-amino ester)s polymers (PHP)-based micellar nanoparticles were synthesized for enhanced doxorubicin (DOX) delivery in drug resistant breast cancer MCF-7/ADR cells. DOX-loaded PHP micelles showed rapid cell-internalization and lysosomal escape in MCF-7/ADR cells. The cytotoxicity assays showed relatively higher cell inhibition of DOX-loaded PHP micelles than that of free DOX against MCF-7/ADR cells. Further mechanistic studies showed that PHP micelles were able to inhibit P-glycoprotein (P-gp) activity by lowering mitochondrial membrane potentials and ATP levels. These results suggested that the enhanced antitumor effect might be attributed to PHP-mediated lysosomal escape and drug efflux inhibition. Therefore, PHP would be a promising pH-responsive nanocarrier for enhanced intracellular drug delivery and overcoming MDR in cancer cells.

Comparison of hyaluronic acid-based micelles and polyethylene glycol-based micelles on reversal of multidrug resistance and enhanced anticancer efficacy in vitro and in vivo

Polyethylene glycol (PEG)-based block copolymer micelles and hyaluronic acid (HA)-based grafted copolymer micelles have been widely investigated in chemotherapy. In this study, to evaluate the differences among HA-based grafted polymer micelles, PEG-based block polymer micelles and the mixed of these two micelles in enhancing antitumor effects and overcoming MDR, two amphiphilic vitamin E succinate (VES) derivatives, HA VES (HA-g-VES) and PEG 2000 VES (TPGS2k), were applied as nanocarriers to prepare HA-VES micelles (HA-PMs), TPGS2k micelles (TPGS2k-PMs) and the mixed micelles (HA/TPGS2k-PMs) for the co-delivery of doxorubicin (DOX) and curcumin (Cur). With the addition of TPGS2k, the particle size of HA/TPGS2k-PMs (153.37 ± 1.00 nm) was smaller than that of HA-PMs (223.83 ± 1.84) but significantly larger than that of TPGS2k-PMs (about 20 nm). The loading efficiency of HA/TPGS2k-PMs was 7.10%, which was lower than HA-PMs (8.31 ± 0.15%) but higher than TPGS2k-PMs (4.38 ± 0.24%). In vitro, HA/TPGS2k-PMs and TPGS2k-PMs exhibited higher cytotoxicity and reversal MDR effects than HA-PMs in MCF-7/Adr cells. However, HA/TPGS2k-PMs, HA-PMs and TPGS2k-PMs all significantly improved the tumor biodistribution, the antitumor effects and reduced the side effects of DOX in 4T1-tumor-bearing mice, but these three micelles displayed no differences in vivo. Therefore, EPR passive targeting effects caused by PEGylated micelles and CD44 active targeting effects caused by HA-based micelles have no significant variance in the delivery of antitumor drugs by i.v.

Bioinspired nanocarriers for an effective chemotherapy of hepatocellular carcinoma

Drug-loaded nanoparticles have been widely researched in the antitumor. However, some of them are unsatisfactory in the long blood circulation and controlled drug release. Red blood cell (RBC) membrane vesicles (RV)-coated nanoparticles have gained more and more attention in drug delivery for their many unique advantages, such as excellent stability, long blood circulation, and reduced the macrophage cells uptake. Herein, by utilizing the advantages of RV, we fabricated RV-coated poly(lactide- co-glycolide) (PLGA)-docetaxel (RV/PLGA/DTX) nanoparticles to enhance the antitumor efficiency in vivo. The RV/PLGA/DTX showed spherical morphology with particle size of about 100 nm and zeta potential at -12.63 mV, which could maintain stability for a long time. The RV/PLGA/DTX significantly enhanced cellular uptake of DTX compared to PLGA/DTX in HepG2 cells. Moreover, RV/PLGA/DTX showed the strongest antitumor effect in vitro. Prolonged blood circulation and enhanced DTX accumulation at the tumor site through enhanced permeability and retention (EPR) effect were achieved by RV/PLGA/DTX, which eventually obtained satisfactory antitumor effect and depressed system toxicity on mice bearing HepG2 xenografts mouse models when compared with free DTX. The hematoxylin and eosin (H&E) and immunofluorescence assays further proved the advantages of RV/PLGA/DTX in vivo antitumor. These RV-coated nanoparticles provide a mimetic therapy, completely inhibited the growth of the HepG2 cells, and with simple compositions, suggesting it to be an ideal strategy for improving the antitumor effect of drug-loaded nanoparticles.

Rational Design of Multifunctional Polymeric Nanoparticles Based on Poly(l-histidine) and d-α-Vitamin E Succinate for Reversing Tumor Multidrug Resistance

A multifunctional nanoparticulate system composed of methoxy poly(ethylene glycol)-poly(l-histidine)-d-α-vitamin E succinate (MPEG-PLH-VES) copolymers for encapsulation of doxorubicin (DOX) was elaborated with the aim of circumventing the multidrug resistance (MDR) in breast cancer treatment. The MPEG-PLH-VES nanoparticles (NPs) were subsequently functionalized with biotin motif for targeted drug delivery. The MPEG-PLH-VES copolymer exerts no obvious effect on the P-gp expression level of MCF-7/ADR but exhibited a significant influence on the loss of mitochondrial membrane potential, the reduction of intracellular ATP level, and the inhibition of P-gp ATPase activity of MCF-7/ADR cells. The constructed MPEG-PLH-VES NPs exhibited an acidic pH-induced increase on particle size in aqueous solution. The DOX-encapsulated MPEG-PLH-VES/biotin-PEG-VES (MPEG-PLH-VES/B) NPs were characterized to possess high drug encapsulation efficiency of approximate 90%, an average particle size of approximately 130 nm, and a pH-responsive drug release profile in acidic milieu. Confocal laser scanning microscopy (CLSM) investigations revealed that the DOX-loaded NPs resulted in an effective delivery of DOX into MCF-/ADR cells and a notable carrier-facilitated escape from endolysosomal entrapment. Pertaining to the in vitro cytotoxicity evaluation, the DOX-loaded MPEG-PLH-VES/B NPs resulted in more pronounced cytotoxicity to MCF-/ADR cells compared with DOX-loaded MPEG-PLH-VES NPs and free DOX solution. In vivo imaging study in MCF-7/ADR tumor-engrafted mice exhibited that the MPEG-PLH-VES/B NPs accumulated at the tumor site more effectively than MPEG-PLH-VES NPs due to the biotin-mediated active targeting effect. In accordance with the in vitro results, DOX-loaded MPEG-PLH-VES/B NPs showed the strongest inhibitory effect against the MCF-7/ADR xenografted tumors with negligible systemic toxicity, as evidenced by the histological analysis and change of body weight. The multifunctional MPEG-PLH-VES/B nanoparticulate system has been demonstrated to provide a promising strategy for efficient delivery of DOX into MCF-7/ADR cancerous cells and reversing MDR.

Soft, adhesive (+) alpha tocopherol phosphate planar bilayers that control oral biofilm growth through a substantive antimicrobial effect

'Soft' nanomaterials have the potential to produce substantive antibiofilm effects. The aim of this study was to understand the oral antimicrobial activity of soft nanomaterials generated from alpha-tocopherol (α-T) and alpha-tocopherol phosphate (α-TP). (+) α-TP formed planar bilayer islands (175 ± 21 nm, -14.9 ± 3.5 mV) in a Trizma® buffer, whereas (+) α-T formed spherical liposomes (563 ± 1 nm, -10.5 ± 0.2 mV). The (+) α-TP bilayers displayed superior Streptococcus oralis biofilm growth retardation, a more substantive action, generated a superior adsorption to hydroxyapatite and showed an enhanced inhibition of multi-species bacterial saliva biofilm growth (38 ± 7μm vs 58 ± 18 μm, P ˂ 0.05) compared to (+) α-T. Atomic force microscopy data indicated that the ability of the 'soft' α-TP nanomaterials to transition into planar bilayer structures upon contact with interfaces facilitated their adhesive properties and substantive antimicrobial effects.

Interfacially active polydopamine for nanoparticle stabilized nanocapsules in a one-pot assembly strategy toward efficient drug delivery

Polydopamine (PDA) nanoparticle stabilized nanocapsules possess great potential for drug delivery via the non-endocytotic pathway.

Recent Advances in the Application of Vitamin E TPGS for Drug Delivery

D-ɑ-tocopheryl polyethylene glycol succinate (Vitamin E TPGS or TPGS) has been approved by FDA as a safe adjuvant and widely used in drug delivery systems. The biological and physicochemical properties of TPGS provide multiple advantages for its applications in drug delivery like high biocompatibility, enhancement of drug solubility, improvement of drug permeation and selective antitumor activity. Notably, TPGS can inhibit the activity of ATP dependent P-glycoprotein and act as a potent excipient for overcoming multi-drug resistance (MDR) in tumor. In this review, we aim to discuss the recent advances of TPGS in drug delivery including TPGS based prodrugs, nitric oxide donor and polymers, and unmodified TPGS based formulations. These potential applications are focused on enhancing delivery efficiency as well as the therapeutic effect of agents, especially on overcoming MDR of tumors. It also demonstrates that the clinical translation of TPGS based nanomedicines is still faced with many challenges, which requires more detailed study on TPGS properties and based delivery system in the future.

Light-activatable dual-source ROS-responsive prodrug nanoplatform for synergistic chemo-photodynamic therapy

In the context of prodrug nanomedicines for cancer therapy, one of the great challenges is the slow and variable release of the parent drug in tumors.

Mesoporous polydopamine nanoparticles with co-delivery function for overcoming multidrug resistance via synergistic chemo-photothermal therapy

Theranostic agents for combined chemo-photothermal therapy have attracted intensive interest in the treatment of multi-drug resistance (MDR) in cancer therapy. However, the development of simple theranostic agents as dual hosts for both heat and a high payload of chemotherapeutic agents remains a big challenge. Herein, mesoporous polydopamine nanoparticles (MPDA) were successfully developed with properties of a high payload of DOX (up to 2000 μg mg^-1) and the drug efflux inhibitor TPGS (d-α-tocopheryl polyethylene glycol 1000 succinate), as well as strong near-infrared absorption. Particularly, DOX and TPGS were sequentially loaded in the pore space and on the external particle surface of MPDA via π-π stacking and hydrophobic interactions, resulting in a MPDA-DOX@TPGS complex. The DOX release observably relies on the pH value and glutathione (GSH). Furthermore, it is possible to accelerate the rate of drug release by NIR irradiation. Importantly, the MPDA-DOX@TPGS complex was found to escape from endosomes after cellular uptake and release the loaded drugs into the cytosol. By TPGS mediated MDR reversal, the delivered DOX induced significant cytotoxicity to MCF-7/ADR cells. Besides, MPDA can absorb the NIR light and convert it into fatal heat to kill the cancer cells. As a consequence, the combined therapy in our system yields a synergistic effect with high therapeutic efficacy.

Reversal of paclitaxel resistance in human ovarian cancer cells with redox-responsive micelles consisting of α-tocopheryl succinate-based polyphosphoester copolymers

P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) is a major obstacle in achieving the therapeutic benefits of paclitaxel (PTX) in the treatment of human ovarian carcinoma. This study is aimed to develop an efficient PTX drug delivery approach to overcome MDR. Redox-responsive micelles consisting of amphiphilic polymers containing disulfide linkages, ie, poly (phosphate ester)-SS-D-α-tocopheryl succinate (POPEA-SS-TOS, PSST) were prepared. PTX-loaded PSST micelles (PTX/PSST-M) designed to display synergistic functions, including reversible inhibition of P-gp, intracellular redox-sensitive release and potent anticancer activities. The average size of PTX/PSST-M was 68.1±4.9 nm. The encapsulated PTX was released quickly through redox-triggered dissociation of micelles. The inhibition of P-gp activity and enhanced cellular accumulation of the PSST micelles were validated. PTX/PSST-M showed significantly increased cytotoxicity against PTX-resistant human ovarian cancer A2780/PTX cells: when the cells were treated with PTX/PSST-M for 48 h, the equivalent IC₅₀ value of PTX was reduced from 61.51 to 0.49 μmol/L. The enhanced cytotoxic effects of PTX/PSST-M against A2780/PTX cells were attributed to their synergistic effects on reducing the mitochondrial transmembrane potential, ATP depletion, ROS production, and activation of apoptotic pathways. Furthermore, PTX/PSST-M significantly increased cell apoptosis/necrosis and cell cycle arrest at the G₂/M phase in A2780/PTX cells. These results demonstrate that the redox-responsive PSST micelles inhibit P-gp activity and have a good potential to effectively reverse PTX resistance in human ovarian carcinoma cells by activating intrinsic apoptotic pathways.

Rational design of hybrid nanomicelles integrating mucosal penetration and P-glycoprotein inhibition for efficient oral delivery of paclitaxel

A dual functional TPGS-succinic acid-mercaptoethylamine (TPGS-SH) material was synthesized to improve the oral absorption of anticancer drugs, aiming to integrate the advantages of mucosal penetration with P-glycoprotein (P-gp) inhibition. Paclitaxel-loaded hybrid nanomicelles (CS-VES/TPGS-SH) with a uniform particle size (234.2-273.9nm), high drug loading (11.50±0.91%), and good encapsulation efficiency (86.18±3.73%) were fabricated. The absorption rate and apparent permeability coefficient were significantly improved in the whole intestine, especially in the duodenum segment, with a 3.68- and 3.22-fold enhancement being detected after perfusion with CS-VES/TPGS-SH hybrid nanomicelles. Moreover, TPGS-SH showed a considerable P-gp inhibition effect with verapamil. CS-VES/TPGS-SH nanomicelles can effectively pass through the mucosal layer and increase the intracellular drug content in duodenum, jejunum, and colon segments as further reflected by the in situ mucosal penetration study. Maximum concentration (C_max) and area under curve (AUC_(0-t)) values of hybrid nanomicelles were improved by 3.39- and 3.58-fold, respectively, compared to those of paclitaxel solution in rats. Therefore, the designed bifunctional hybrid CS-VES/TPGS-SH nanomicelles could function as efficient drug carriers, facilitating the oral absorption of hydrophobic anticancer drugs.

Improved Bioavailability and Antitumor Effect of Docetaxel by TPGS Modified Proniosomes: In Vitro and In Vivo Evaluations

A novel oral drug delivery system, TPGS modified docetaxel proniosomes (DTX-TPGS-PNs), was designed to enhance the oral bioavailability and antitumor efficiency of the poorly water-soluble drug docetaxel. DTX-TPGS-PN niosomes were 93 ± 6.5 nm in size, -18.53 ± 1.65 mV in zeta potential and exhibited spherical morphology, with an encapsulation efficiency of 97.31 ± 0.60%. The system showed sustained release in both simulated gastric and intestinal fluid. The results of caco-2 monolayer, everted gut sac model and improved single-pass intestinal perfusion model transport studies showed that DTX-TPGS-PN niosomes could significantly improve the absorption of DTX. The pharmacokinetics study suggested the absolute bioavailability of DTX-TPGS-PN niosomes were 7.3 times that of DTX solution. In addition, a higher antitumor efficacy than DTX solution was demonstrated in MCF-7 and MDA-MB-231 cells in vitro and in MCF-7 tumor-bearing mice model in vivo. Our results demonstrated DTX-TPGS-PN is promising in enhancing the bioavailability and efficiency of poorly water-soluble drug DTX, and the potential of proniosomes as stable precursors for oral drug delivery.

Co-assembly of doxorubicin and curcumin targeted micelles for synergistic delivery and improving anti-tumor efficacy

Chemotherapeutic drugs have a series of limitations in anti-tumor treatment, mainly including multidrug resistance (MDR) and serious adverse reactions. Co-delivery system with two or more synergistic therapeutic drugs is an effective strategy to settle these limitations. In this study, active tumor-targeted co-delivery micelles (DOX+Cur)-PMs, with two synergistic drugs of a therapeutic drug of doxorubicin (DOX) and a chemosensitizer of curcumin (Cur) co-encapsulated into hyaluronic acid-vitamin E succinate (HA-VES) graft copolymer, were prepared and delivered simultaneously into tumor cells for improving therapeutic effects of DOX. (DOX+Cur)-PMs had uniform particle size, high encapsulation efficacy, sustained release profile and good colloidal stability. In vitro cytotoxicity study, (DOX+Cur)-PMs exerted the strongest cytotoxicity and highest cell apoptosis-inducing activities against DOX-resistant MCF-7/Adr cells. Moreover, (DOX+Cur)-PMs more efficiently internalized into cancer cells and enhanced the cellular uptake of DOX via energy-dependent and caveolae-mediated endocytosis, and significantly reversed MDR effects via CD44 targeting delivery and the synergic effect of released Cur. More importantly, in vivo results illustrated that (DOX+Cur)-PMs not only displayed better tumor accumulation and tumor targeting, and more efficiently inhibited the growth of tumor in 4T1 tumor-bearing mice, but also induced significantly less pathological damage to the cardiac tissue in comparison with free DOX, even DOX-PMs and DOX-PMs+Cur. In summary, this targeted combinational micellar delivery system with DOX and Cur could be a promising vehicle in tumor therapy.

The in vivo fate of nanocrystals

There has been significant research interest in, and development of, nanocrystals in recent years for the delivery of poorly water-soluble drugs via various routes. However, there is a common misinterpretation of nanocrystallization as an approach to modulate, and more specifically to enhance, the dissolution of drug crystals. Nevertheless, it is possible for nanocrystals to interact with biological tissues because nanocrystals can survive for a longer duration in vivo compared with solution counterparts. Therefore, understanding the in vivo fate of nanocrystals and determining its contribution to efficacy is of tremendous significance for optimizing the performance of nanocrystals. Here, we critically review the general hypotheses related to the in vivo fate of nanocrystals.

Amphiphilic copolymer and TPGS mixed magnetic hybrid micelles for stepwise targeted co-delivery of DOX/TPP–DOX and image-guided chemotherapy with enhanced antitumor activity in liver cancer

Stepwise targeted and image-guided chemotherapy with enhanced antitumor activity in liver cancer.

Facile Fabrication of Tumor Redox-Sensitive Nanoassemblies of Small-Molecule Oleate Prodrug as Potent Chemotherapeutic Nanomedicine

The conjugate of paclitaxel (PTX) and docosahexaenoic acid has entered into clinical trials. However, the most recent clinical outcomes fell short of expectations, due to the extremely slow drug release from the hydrophobic conjugates. Herein, a novel prodrug-based nanoplatform self-assembled by the disulfide bond linked conjugates of PTX and oleic acid for rapid and differential release of PTX in tumor cells is reported. This redox-responsive prodrug-nanosystem demonstrates multiple therapeutic advantages, including one-step facile fabrication, high drug-loading efficiency (56%, w/w), on-demand drug release responding to redox stimuli, as well as favorable cellular uptake and biodistribution. These advantages result in significantly enhanced antitumor efficacy in vivo, with the tumor almost completely disappearing in mice. Such a uniquely engineered prodrug-nanosystem has great potential to be used as potent chemotherapeutic nanomedicine in clinical cancer therapy.

The effect of dual-functional hyaluronic acid-vitamin E succinate micelles on targeting delivery of doxorubicin

Tumor-targeted delivery system has been developed as an attractive strategy for effective tumor therapy. In this study, in order to enhance the antitumor effects of doxorubicin (DOX), amphiphilic hyaluronic acid (HA)-conjugated vitamin E succinate (VES) copolymers (HA-VES) with different degrees of substitution (DS) were prepared with synergistic antitumor effects and active targeting activities, and utilized as nanocarriers for the efficient delivery of DOX. DOX-loaded HA-VES polymeric micelles (HA-VES/DOX) self-assembled from dual-functional HA-VES copolymer and exhibited excellent loading efficiency and superior colloidal stability. In vitro, HA-VES/DOX displayed enhanced cytotoxicity with synergistic anticancer effects of HA-VES copolymer, high apoptosis-inducing activities of tumor cells, and reversal effects of DOX on multidrug resistance, in comparison with DOX. Also, in vitro cellular uptake and subcellular localization studies revealed that HA-VES/DOX could more efficiently internalize into cancer cells and selectively release DOX within lysosomes, thereby enhancing the distribution of DOX in nuclei and facilitating its interactions with DNA. Specifically, HA-VES/DOX decreased the activity of CD44 mRNA and improved the targeting efficiency on MCF-7 cells, based on the active recognition between HA and CD44 receptor. More importantly, HA-VES/DOX displayed better tumor accumulation and targeting, and enhanced antitumor efficacy with reduced systemic toxicity in 4T1 tumor-bearing mice. In summary, the developed HA-VES-based drug delivery system, which increased drug targeting on the tumor site and exhibited preferable anticancer activity, could hold great potential as an effective and promising strategy for efficient tumor therapy.