DOX-loaded Micelles Research Articles

H2O2-responsive polymeric micelles with a benzil moiety for efficient DOX delivery and AIE imaging.

Nano drug delivery is a promising domain in biomedical theranostics and has aroused more and more attention in recent years. We report here an amphiphilic polymer TPG1, bearing a H2O2-sensitive benzil and an AIE fluorophore tetraphenylethene (TPE) unit, which is able to self-assemble into spherical nanosized micelles in aqueous solution. Doxorubicin (DOX) can be encapsulated into TPG1 micelles efficiently with the loading capability of up to 59% by weight. The benzil moiety could be cleaved via the Baeyer-Villiger type reaction in the presence of H2O2, leading to the decomposition of TPG1 micelles and release of DOX. In vitro studies indicated that DOX-loaded TPG1 micelles can be internalized by cancer cells, followed by unloading encapsulated DOX under the stimulation of H2O2. The drug release process can be monitored by the AIE fluorescence from the degradation products containing a TPE moiety. MTT assays against HeLa and HepG2 cancer cells demonstrated that DOX-loaded micelles showed good anticancer efficacy. The polymer TPG1 and the corresponding decomposed products showed great biocompatibility. Our data suggest that TPG1 has the potential to be employed for the controlled drug delivery system.

Hypoxia-responsive micelles self-assembled from amphiphilic block copolymers for the controlled release of anticancer drugs.

Amphiphilic block copolymers poly(ethylene glycol)-block-poly(methacrylic acid-co-2-nitroimidazole methacrylate) (PEG-b-P(MAA-co-NIMA)) were synthesized by the combination of atom transfer radical polymerization (ATRP), hydrolysis and EDC reactions. These copolymers could self-assemble into spherical micelles in water. 2-Nitroimidazole (NI) groups presented hypoxia-responsive properties under hypoxia conditions. The hydrophobic NI groups could be converted into hydrophilic aminoimidazole (AI) groups, which would lead to the expansion of micelles. Moreover, the content of NI groups in the copolymers would affect the hydrophilic-hydrophobic balance and therefore influence the self-assembly behaviour of the copolymer and the morphologies of the micelles. The copolymer micelles were used as a drug delivery system for controlled release of anticancer drug doxorubicin (DOX). The in vitro cytotoxicity investigation revealed that the DOX-loaded micelles showed higher toxicity to hypoxic cells than to normoxic cells. As a result, the block copolymers are expected to be used as an intelligent carrier for hydrophobic drugs to treat hypoxia-associated diseases.

PH and reduction dual-responsive micelles based on novel polyurethanes with detachable poly(2-ethyl-2-oxazoline) shell for controlled release of doxorubicin

We describe a biodegradable amphiphilic polyurethane (PU) with disulfide bonds in the main chain [PEtOz-b-PU(SS)-b-PEtOz]. This multi-block PU was synthesized using poly (ε-caprolactone) diol (PCL-SS-PCL) and poly (2-ethyl-2-oxazoline) (PEtOz-OH) as soft segments, and bis (2-isocyanatoethyl) disulfide as the hard segment. Acid-sensitive PEtOz-OH was used as a hydrophilic segment for pH sensitivity. And reduction sensitivity was induced via disulfide bonds incorporated into the hydrophobic poly (ε-caprolactone) segment of the amphiphilic PUs. The system can self-assemble to form micelles responsive to pH and reducing conditions. The properties of the micelle were studied with dynamic light scattering and scanning electron microscopy. Doxorubicin (DOX) was chosen as a model drug. The in vitro release studies showed that PEtOz-b-PU(SS)-b-PEtOz micelle could degrade more rapidly and completely in a reductive and acidic environment [10 mM dl-Dithiothreitol, pH 5.0]. The methyl tetrazolium (MTT) assay and fluorescent microscopy confirmed the cytotoxicity of the DOX-loaded micelles. This work provides a promising dual-responsive drug carrier based on amphiphilic PU to achieve efficient drug delivery.

Investigation of pH-responsive block glycopolymers with different structures for the delivery of doxorubicin.

To understand the influence of the construction of pH-responsive glycopolymer carriers on loading and release behaviors of the drug, three types of block glycopolymers with similar compositions but different constructions, PEG-b-P(DEA-co-GAMA), PEG-b-PDEA-b-PGAMA and PEG-b-PGAMA-b-PDEA, were successfully synthesized via atom transfer radical polymerization (ATRP) method. The compositions and structures of the three glycopolymers were characterized using 1H NMR (nuclear magnetic resonance) and GPC (gel permeation chromatography), while the morphology and size of aggregates from pH-sensitive block glycopolymers were measured using TEM (transmission electron microscopy) and DLS (dynamic light scattering). The results indicated that the micelles prepared from PEG-b-PGAMA-b-PDEA had a more compact shell structure. The drug-loaded micelles were prepared using the diafiltration method at pH 10, and the loading content and loading efficiency were analyzed using a UV-visible spectrophotometer. DOX-loaded micelles formed by PEG-b-PGAMA-b-PDEA with the more compact shell construction showed the highest loading content and loading efficiency (12.0 wt% and 58.0%) compared with the other two micelles. Moreover, the DOX release tests of these micelles were carried out under two PBS conditions (pH 7.4 and pH 5.5), and the DOX release amount in a certain time was analyzed using a UV-visible spectrophotometer. The results showed that the more compact shell construction of the three layered micelle obstructed the diffusion of a proton into the PDEA core at pH 5.5 and delayed the drug from releasing under both conditions. Moreover the two-layered micelle with a PDEA and PGAMA mixed core showed a relatively high release amount owing to the porous core permitting unimpeded releasing at pH 7.4 and promoted the protonation of PDEA at pH 5.5. Insights gained from this study show that the structure of block copolymers, leading to different constructions of micelles, could adjust the drug loading and release behavior to certain extent, thus it may contribute to improving the design of desirable drug delivery systems.

MMP-responsive in situ forming hydrogel loaded with doxorubicin-encapsulated biodegradable micelles for local chemotherapy of oral squamous cell carcinoma.

The complex construction within the oral cavity causes incomplete surgical resection of oral squamous cell carcinoma (OSCC) that may enhance the risk of recurrence and metastasis in the treatment. In situ forming injectable hydrogels with minimally invasive procedures, encapsulation stability and stimuli-responsive degradation have emerged as promising carriers for local drug delivery. In this study, doxorubicin (DOX) was first encapsulated in biodegradable poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PDLLA-PEG-PDLLA) micelles and then loaded into an in situ injectable hyaluronic acid (HA) hydrogel, which was cross-linked by a matrix metalloproteinase-2 (MMP-2)-responsive peptide (GCRDGPQGIWGQDRCG) through a Michael addition reaction. In vitro studies demonstrated that the HA hydrogel had a sensitive MMP-2-responsive drug release profile. Investigations including MTT, live-dead, apoptosis, and wound healing assays illustrated that DOX micelle-loaded HA hydrogels exhibited outstanding cytotoxicity against squamous carcinoma cells (SCC-15). Furthermore, by in vivo studies, we also proved that HA hydrogels degraded faster in the tumor site than in normal tissue, which led to a local sustained release of DOX-loaded micelles and tumor growth inhibition of oral squamous cell carcinoma (OSCC) without any damage to the organs. Therefore, this work provides a remarkable drug delivery platform for local chemotherapy and other applications.

Redox-responsive biocompatible nanocarriers based on novel heparosan polysaccharides for intracellular anticancer drug delivery

Heparosan is a natural precursor of heparin biosynthesis in mammals. It is stable in blood circulation but can be degraded in lysosomes, showing good biocompatibility and long circulation features. So heparosan can be designed as anticancer drug carriers to increase tumor selectivity and improve the therapeutic effect. A novel redox-sensitive heparosan-cystamine-vitamin E succinate (KSV) micelle system was constructed for intracellular delivery of doxorubicin (DOX). Simultaneously, the redox-insensitive heparosan-adipic acid dihydrazide-vitamin E succinate copolymer (KV) was synthesized as control. DOX-loaded micelles (DOX/KSV) with an average particle size of 90–120 nm had good serum stability and redox-triggered depolymerization. In vitro drug release test showed that DOX/KSV micelles presented obvious redox-triggered release behavior compared with DOX/KV. Cytotoxicity and cell uptake were investigated using MGC80-3 tumor cells and COS7 fibroblast-like cells. The cell survival rate of blank micelles was more than 90%, and the cytotoxicity of DOX/KSV in MGC80-3 cells was higher than in COS7 cells, indicating that the carrier has better biocompatibility and less toxicity side effect. The cytotoxicity of DOX/KSV against MGC80-3 cells was significantly greater than that of free DOX and DOX/KV. Furthermore, compared with DOX/KV in MGC80-3 cells, DOX/KSV micelles uptook more anticancer drugs and then released DOX faster into the cell nucleus. The micelles were endocytosed by multiple pathways, but clathrin-mediated endocytosis was the main pathway. Therefore, heparosan polysaccharide could be a potential option as anticancer carrier for enhancing efficacy and mitigating toxicity.

Polylactide-Cholesterol Stereocomplex Micelle Encapsulating Chemotherapeutic Agent for Improved Antitumor Efficacy and Safety.

For efficient therapy, optimized polymer micelle drug delivery systems require stability during circulation, appropriate diameters for targeting, and controlled drug release at the lesion site. To enhance the stability, adjust the sizes, and improve the selectivity of drug release of micelles from polylactides and polypeptides, stereocomplex interaction has been introduced. Herein, the cholesterol (CHOL)-enhanced doxorubicin (DOX)-loaded poly(D-lactide)-based micelle (CDM/DOX), poly(L-lactide)-based micelle (CLM/DOX), and stereocomplex micelle (SCM/DOX) from the equimolar mixture of the enantiomeric 4-armed poly(ethylene glycol)-polylactide copolymers were reported to enhance tumor cell uptake and control drug release for treatment of cervical carcinoma. The introduction of hydrophobic CHOL further upregulated the stability, drug-loading capability, and cell uptake of micelles. All these DOX-loaded micelles showed appropriate sizes of ∼100 nm for the enhanced permeability and retention (EPR) effect. Compared to CDM/DOX and CLM/DOX, SCM/DOX exhibited the highest cell uptake and the most efficient antitumor efficacy in vitro. For U14 cervical carcinoma mouse model, all of the DOX-loaded micelles, especially SCM/DOX, effectively inhibited the progression of cervical carcinoma, as demonstrated by nearly stagnant tumor growth and increased apoptosis and necrosis areas within tumor tissue. Furthermore, these DOX-loaded micelles effectively alleviated the systemic toxicity of DOX. All the above results suggest that the DOX-loaded micelles, especially SCM/DOX, are an ideal drug delivery system for combating cervical carcinoma.

PH-Sensitive DOX-Loaded PAA-PF127-PAA Micelles Combined with Cryotherapy for Treating Walker 256 Carcinosarcoma in a Rat Model.

In this work, a novel combination of drug therapy and cryotherapy for tumor treatment was developed. Pluronic F127 modified with poly(acrylic acid) at two terminals (denoted as PAA-PF127-PAA) was used as carriers for doxorubicin (DOX) delivery. Due to the pH-sensitive property endowed by PAA, the DOX-loaded PAA-PF127-PAA micelles released DOX faster in the slightly acidic physiological environment of the tumor site than that in the neutral physiological environment. Three-group rats bearing Walker 256 carcinosarcoma were respectively treated with cryotherapy, combination of DOX-loaded micelles and cryotherapy, and saline injection to investigate the effect of the combined therapy. The apoptosis rate of TdT-mediated dUTP nick-end labeling (TUNEL) slices indicated that compared with cryotherapy alone, the DOX-loaded PAA-PF127-PAA micelles combining with cryotherapy showed increased apoptosis. Thus, the combination of drug therapy and cryotherapy can be used as an effective technique for tumor treatment.

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.

Bio-inspired keratin-based core-crosslinked micelles for pH and reduction dual-responsive triggered DOX delivery

Facile bio-inspired approach has been developed to prepare novel DOX-loaded chicken feather keratin-based core-crosslinked micelles (DOX/Ker-PEG CCMs) for pH and reduction dual-responsive tumor-specific intracellular triggered DOX delivery, by oxidation crosslinking the DOX/Ker-PEG micelles which were simply self-assembled by adjusting solution pH value to 10. The final DOX/Ker-PEG CCMs with a mean hydrodynamic diameter of 152 nm were obtained with a drug loading capacity (DLC) of 24.8%. The in vitro controlled release profiles demonstrated the pH and reduction dual-responsive triggered release of DOX from the developed bio-inspired drug delivery system (DDS), with a cumulative release of 58% within 3 days in a sustained release manner in the stimulated tumor intracellular microenvironment, while a low premature drug leakage of 14% occurred in the normal physiological medium. Furthermore, the MTT assays demonstrated that the graft copolymer Ker-PEG58 possessed excellent cytocompatibility, while the DOX/Ker-PEG CCMs exhibited an enhanced anti-tumor efficacy on the HepG2 cells than the free DOX.

Deep Eutectic Solvent-Mediated FA-g-β-Alanine-co-PCL Drug Carrier for Sustainable and Site-Specific Drug Delivery.

An amphiphilic polymer that consisted of a deep eutectic solvent (DES)-mediated drug carrier was designed, where the DES influenced the formation of folic acid (FA)-tagged g-β-alanine-co-PCL polymer (DES@FA-g-β-alanine-co-PCL); the nature of the carrier was investigated through emission analysis and pyrene used as a model probe (CMC = 0.4 mg/mL). The amphiphilic polymer was self-assembled into a sphere (≈204 nm diameter) with a surface charge of -3 ± 0.5 mV. The doxorubicin was incorporated and the structural changes were analyzed by UV-visible spectroscopy, FT-IR, XRD, Raman, and TGA analysis, while size and morphological analysis was performed by DLS, AFM, SEM, and TEM. The controlled release of drug from the carrier was observed at different pH levels. The enhanced anticancer potential of DOX-loaded polymeric micelle was studied both in vitro and in vivo breast cancer model. The treatment of DOX-loaded polymeric micelle reduces the viability and proliferation of MDA-MB-231 cells. From the results of the current investigation it concludes that the DOX-loaded polymeric micelle has enhance anticancer effect and it exhibits its potential effect at the dosage of 5 mg/kg body weight in mammary carcinoma-bearing rats. From the observed results, synthesized DOX-loaded polymeric micelle holds strong anticancer properties compared with free DOX and can be used as a potential carrier in the pharmaceutical industry.

Synthesis, self-assembly, and pH-responsive drug release of PHMEMA-PEG-PHMEMA ABA triblock copolymers

A series of tertiary amine containing PHMEMA-PEG-PHMEMA ABA triblock copolymers were synthesized by atom transfer radical polymerization (ATRP) using bromine-capped poly(ethylene glycol) (Br-PEG-Br) and 2-(hexamethyleneimino)ethyl methacrylate (HMEMA) as macro-initiator and monomers, respectively. The chemical structures and molecular weights of triblock copolymers were characterized by 1H NMR and gel permeation chromatography (GPC). The self-assembly behaviors of copolymers in different pH conditions were studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Triblock copolymers self-assembled into micelles in water (pH 7.4) and the micelles disassembled at acidic pH (pH 5.0). Anticancer drug doxorubicin (DOX) was used as a drug model and physically encapsulated into polymeric micelles. The drug release of DOX-loaded polymeric micelles was pH-responsive; the drug-loaded micelles that had higher contents of tertiary amine in polymer pendant groups showed faster release speed. In addition, the drug-loaded micelles showed excellent inhibition efficacy against HeLa cells in vitro.

Free Adriamycin-Loaded pH/Reduction Dual-Responsive Hyaluronic Acid-Adriamycin Prodrug Micelles for Efficient Cancer Therapy.

Currently, tumor-targeted nanocarriers self-assembled from amphiphilic polymer-drug conjugates are of great demand. The appeal of these carriers arises mainly through their excellent loading efficiency of homologous drug molecules with microenvironment-triggered drug release. Herein, doxorubicin (DOX) was constructed to a hyaluronic acid (HA) backbone through hydrazone and disulfide linkages to construct pH and reduction coresponsive prodrug conjugates (HA-ss-DOX). During formulation, the amphipathic HA-ss-DOX spontaneously assembled into distinct core/shell micelles in aqueous media and showed conspicuous physical DOX loading capabilities (29.1%, DOX/HA-ss-DOX) based on homologous compatibility. DOX/HA-ss-DOX micelles were shown to be stable in normal physiological environments, while accomplishing selective, rapid DOX release at acidic pH and/or highly reducing conditions. The efficacy of DOX/HA-ss-DOX micelles was tested on A549 human lung cancer cells, wherein flow cytometry and confocal microscopy analysis revealed their HA receptor-mediated endocytosis mechanism. In comparison, DOX-loaded redox-insensitive micelles (DOX/HA-DOX) still demonstrated pH-dependent drug release. However, a more rapid intracellular DOX release profile was achieved in DOX/HA-ss-DOX micelles because of their sensitivity to both acidic and reducing environments. Resultantly, DOX/HA-ss-DOX exhibited the strongest cytotoxicity and apoptosis-inducing ability among all tested groups when tested on an A549 cell line and xenograft model.

AB2-type miktoarm poly(l-lactide)-b-poly(N-acryloylmorpholine) amphiphilic star block copolymers as nanocarriers for drug delivery

In this study, a series of amphiphilic AB2-type miktoarm star block copolymers consisting of hydrophobic poly(l-lactide) (PLLA) as a A arm and hydrophilic poly(N-acryloylmorpholine) (PNAM) as two B arms were synthesized via the combination of ring opening polymerization and xanthate-mediated reversible addition-fragmentation chain transfer polymerization. Resultant polymers were analyzed by 1H NMR spectroscopy and gel permeation chromatography. Aggregation properties of the amphiphilic miktoarm star block copolymers were studied by fluorescence spectroscopy, transmission electron microscopy and dynamic light scattering. Doxorubicin (DOX) was successfully loaded into the miktoarm star block copolymer micelles and the DLC and DLE of the DOX-loaded micelles increased (9.4 to 13.6% and 55.6 to 78.7%) with an increase in the hydrophilic PNAM chain length of the miktoarm star block copolymer. The result revealed that DOX release was enhanced as the pH reduced from 7.4 to 6.4 and the rate of release slightly increased with increasing the PNAM hydrophilic chain length of the micelles.

Designing heparan sulfate-based biocompatible polymers and their application for intracellular stimuli-sensitive drug delivery

Heparan sulfate (HS) is a kind of natural polysaccharides with good biocompatibility. And as drug carriers, it has some advantages compared to heparin. However, the preparation of HS is cumbersome and difficult, which limits its application in drug delivery. Here, we use modern separation technique combined with chromatography to establish a new preparation method of HS. The molecular weight and degree of dispersion of HS were (1.03 × 104 ± 107) kDa and 1.106, respectively. HS also showed low anticoagulation activity in comparison with heparin. Subsequently, novel redox-sensitive heparan sulfate-cystamine-vitamin E succinate (HS-SS-VES, HSV) micelles were designed to increase tumor selectivity and improve the therapeutic effect of doxorubicin (DOX). DOX-loaded HSV micelles (DOX/HSV) with spherical morphology had average particle size of 90–120 nm and good redox-triggered release behavior. The cell viabilities of blank micelles were >90% in both human breast cancer (MCF7) cells and African green monkey SV40-transformed kidney fibroblast (COS7) cells. However, the cytotoxicity of DOX/HSV in MCF7 cells was higher than that of COS7 cells. Flow cytometry analyses and confocal laser scanning microscopy observation indicated that DOX/HSV micelles were internalized by endocytosis, and then the drug was released quickly and entered the nuclei of tumor cells. The results demonstrate that high-purity HS can be prepared and has the potential to be further used for drug delivery in antitumor applications.

Reduction-responsive amphiphilic star copolymers with long-chain hyperbranched poly(ε-caprolactone) core and disulfide bonds for trigger release of anticancer drugs

In this contribution, the reduction-responsive star copolymers with long-chain hyperbranched poly(ε-caprolactone) (PCL) (HyperMacs) core and disulfide bonds were synthesized via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The HyperMacs core was constructed from disulfide-containing AB2-type PCL macromonomers, which possesses length-adjustable chain segments between branching points, large cavities, low degree of crystallinity, and reduction-responsivity. After grafted with poly(ethylene glycol), the reduction-responsive star copolymers can self-assemble into micelles in aqueous solution. The obtained micelles exhibited much lower critical micelle concentration (CMC) than their linear analogues. The reduction-responsivity from disulfide bonds makes them a promising carrier candidate for trigger release of anticancer drugs. The in vitro release results confirmed that their doxorubicin (DOX)-loaded micelles exhibited desirable reduction-triggered release performance. The cellular proliferation inhibition against HepG2 cells demonstrated that the DOX-loaded micelles showed a comparable anticancer activity with free DOX. Therefore, it can be expected that the reduction-sensitive micelles may serve as smart vehicles for intracellular delivery of anti-cancer drugs in tumour therapy.

Negative Surface Shielded Polymeric Micelles with Colloidal Stability for Intracellular Endosomal/Lysosomal Escape.

The critical process and step in achieving effective antitumor therapies is facilitating endosomal escape, which can enhance the intracellular target delivery of therapeutics. However, the normally adopted approaches tend to result in colloidal instability as a result of the inevitable interactions between the resulting positively charged surfaces of micelles and proteins in vivo. Herein, negatively charged surface shielded polymeric micelles, consisting of polymethylacrylamide derivatives and hydrophilic chitosan ( Mw = 18.8 kDa) linked by 3,3'-dithiodipropionic, are constructed. Until the pH decreases to less than 4.5, the DOX-loaded polymeric micelles (CSO-SS-PDPA/DOX) retain a negative surface charge as a result of the abundant amide groups, which could resist formation of the protein "corona" as visualized by transmission electron microscopy. Robust endosomal escape within tens of minutes due to protonated amine groups and specific redox-responsive drug release is visualized by confocal microscopy. The superior therapeutic efficacy in both 3D tumor spheroids and MCF-7 bearing mice further suggested that the prepared CSO-SS-PDPA/DOX is a promising approach for maintaining colloidal stability while achieving intracellular endosomal/lysosomal escape, which opens new opportunities for drug delivery.

PH-sensitive amphiphilic triblock copolymers containing ortho ester main-chains as efficient drug delivery platforms

Triblock copolymer PEG-block-poly(ortho ester urethane)-block-PEG (PEG-POEU-PEG) was conveniently prepared via polycondensation reaction between the ortho ester-containing diol and hexamethylene diisocyanate (HDI) at varying reaction time followed by termination with polyethylene glycol monomethyl ether (mPEG). PEG-POEU-PEG could further self-assemble into nano-scaled micelles. Ortho ester degradation in these micelles was significantly accelerated at pH 5.0 due to its pH sensitivity. In vitro drug release profiles showed that only a small amount of the loaded DOX was released in PBS solution at pH 7.4, while DOX could be quickly released at pH 5.0. MTT assay reveals that the micelles were completely nontoxic to cultured cells. Moreover, DOX-loaded micelles exhibited efficient antitumor efficiency against cancer cells. Therefore, the micelles may be potential drug carriers in cancer therapy.

Controlled Drug Delivery by Polylactide Stereocomplex Micelle for Cervical Cancer Chemotherapy.

A stable doxorubicin (DOX)-loaded stereocomplex micelle drug delivery system was developed via the stereocomplex interaction between enantiomeric 4-armed poly(ethylene glycol)–poly(D-lactide) and poly(ethylene glycol)–poly(L-lactide) to realize control drug release and improve tumor cell uptake for efficient cervical carcinoma therapy. All these DOX-loaded micelles including poly(D-lactide)-based micelle (PDM/DOX), poly(L-lactide)-based micelle (PLM/DOX), and stereocomplex micelle (SCM/DOX) exhibited appropriate sizes of ∼100 nm for the enhanced permeability and retention (EPR) effect. In addition, compared to PDM/DOX and PLM/DOX, SCM/DOX exhibited the slowest DOX releaser, highest tumor cell uptake and the most efficient tumor cell suppression in vitro. Moreover, the excellent tumor inhibiting rates of the DOX-loaded micelles, especially SCM/DOX, were verified in the U14 cervical carcinoma mouse model. Increased tumorous apoptosis and necrosis areas were observed in the DOX-loaded micelles treatment groups, especially the SCM/DOX group. In addition, all these DOX-loaded micelles obviously alleviated the systemic toxicity of DOX. As a result, SCM can be a promising drug delivery system for the future therapy of cervical carcinoma.

A Nanomicellar Prodrug Carrier Based on Ibuprofen-Conjugated Polymer for Co-delivery of Doxorubicin.

Ibuprofen (IBU) is a non-steroidal anti-inflammatory drug (NSAID), which is widely used to reduce fever and treat inflammation and acute pain. Recently, its application in cancer treatment is also being explored. In this work, we synthesized a well-defined IBU-based amphiphilic diblock copolymer via reversible addition fragmentation transfer (RAFT) polymerization of IBU-based vinyl monomer. The amphiphilic copolymer POEG-b-PVBIBU (denoted as POVI) was composed of a hydrophilic poly(oligo(ethylene glycol)) block and a hydrophobic IBU-bearing prodrug block, which was able to self-assemble into prodrug nanomicelles. In addition, it could serve as a carrier to co-load other drugs including doxorubicin (DOX), paclitaxel (PTX), and docetaxel (DTX). By using DOX as a model anti-cancer drug, the delivery function of POVI carrier, including the drug release, in vitro cytotoxicity, cellular uptake, and in vivo antitumor activity, was evaluated. DOX-loaded POVI micelles exhibited sustained release of DOX. Besides, DOX/POVI micelles were effectively taken up by tumor cells with an efficiency comparable to that of free DOX. Moreover, in vivo studies showed that POVI carrier itself had modest antitumor activity. After loading DOX, the antitumor activity was significantly increased, which was significantly higher than that of free DOX. Our results suggest that POVI polymer represents a simple and effective dual-functional carrier for co-delivery of IBU and DOX to improve the anticancer activity.