High tolerated paclitaxel nano-formulation delivered by poly (lactic-co-glycolic acid)-g-dextran micelles to efficient cancer therapy

Drug Efficacy Comparison of pH-Sensitive and Non-pH-Sensitive Taxol Delivery Nanoparticles in Cancer Therapy

Taxol is one of the most widely used chemotherapeutic agents but is restricted by its poor solubility and severe side effects in clinical practice. To overcome these limitations, pH-sensitive nanoparticles, Acetalated Dextran6k-PEG5k-PLA2k-Taxol (ADPP-PTX), non-pH-sensitive nanoparticles, and Propionic Anhydride modified Dextran6k-PEG5k-PLA2k-Taxol (PDPP-PTX) are developed for the delivery of Taxol. Compared with PDPP-PTX, ADPP-PTX shows higher sensitivity to acid response and greater anti-proliferative effect on cancer cells. In the in vivo study, ADPP-PTX treatment effectively suppresses the growth of tumors, while only half the dose of Taxol is used, which significantly reduces systemic toxicity compared with Taxol and PDPP-PTX.

Improved Antitumor Efficacy of a Dextran-based Docetaxel-coupled Conjugate against Triple-Negative Breast Cancer

BACKGROUND

Most chemotherapeutic agents are characterized by poor water solubility and non-specific distribution. Polymer-based conjugates are promising strategies for overcoming these limitations.

OBJECTIVE

This study aims to fabricate a polysaccharide, dextran-based, dual-drug conjugate by covalently grafting docetaxel (DTX) and docosahexaenoic acid (DHA) onto the bifunctionalized dextran through a long linker, and to investigate the antitumor efficacy of this conjugate against breast cancer.

METHODS

DTX was firstly coupled with DHA and covalently bounded with the bifunctionalized dextran (100 kDa) through a long linker to produce a conjugate dextran-DHA-DTX (termed C-DDD). Cytotoxicity and cellular uptake of this conjugate were measured in vitro. Drug biodistribution and pharmacokinetics were investigated through liquid chromatography/mass spectrometry analysis. The inhibitory effects on tumor growth were evaluated in MCF-7- and 4T1-tumor-bearing mice.

RESULTS

The loading capacity of the C-DDD for DTX was 15.90 (weight/weight). The C-DDD possessed good water solubility and was able to self-assemble into nanoparticles measuring 76.8 ± 5.5 nm. The maximum plasma concentration and area under the curve (0-∞) for the released DTX and total DTX from the C-DDD were significantly enhanced compared with the conventional DTX formulation. The C-DDD selectively accumulated in the tumor, with limited distribution was observed in normal tissues. The C-DDD exhibited greater antitumor activity than the conventional DTX in the triplenegative breast cancer model. Furthermore, the C-DDD nearly eliminated all MCF-7 tumors in nude mice without leading to systemic adverse effects.

CONCLUSION

This dual-drug C-DDD has the potential to become a candidate for clinical application through the optimization of the linker.

Perspectives on cutting-edge nanoparticulate drug delivery technologies based on lipids and their applications

Numerous nanotech arenas in therapeutic biology have recently provided a scientific platform to manufacture a considerable swath of unique chemical entities focusing on drugs. Recently, nanoparticulate drug delivery systems have emerged to deliver a specific drug to a specified site. Among all other carriers, lipids possess features exclusive to nanostructured dosage forms. The bioavailability of orally administered drugs is typically negatively affected by their poor water solubility, resulting from the unique chemical moieties introduced. Because of their unique advantages, lipid nanoparticles must become increasingly predictable as a robust delivery mechanism. The enhanced biopharmaceutical properties and significance of lipid-based targeting technologies such as liposomes, niosomes, solid lipid nanoparticles and micelles are highlighted in this review. Pharmaceutical implications of lipid nanocarriers for the transport and distribution of various therapeutic agents, such as biotechnological products and small pharmaceutical molecules, is a booming topic. Lipid nanoparticles as drug delivery systems have many appealing properties, including high biocompatibility, ease of preparation, tissue specificity, avoidance of reticuloendothelial systems, delayed drug release, scale-up feasibility, nontoxicity and targeted delivery. The use of lipid nanoparticles to enhance the transport of biopharmaceuticals is currently considered state-of-the-art. Similarly, we critically examine the upcoming guidelines that therapeutic scientists should handle.

Evaluation of poly (lactic-co-glycolic acid) nanoparticles to improve the therapeutic efficacy of paclitaxel in breast cancer

Introduction: Paclitaxel (PTX) is a cornerstone in the treatment of breast cancer, the most common type of cancer in women. However, this drug has serious limitations, including lack of tissue-specificity, poor water solubility, and the development of drug resistance. The transport of PTX in a polymeric nanoformulation could overcome these limitations. Methods: In this study, PLGA-PTX nanoparticles (NPs) were assayed in breast cancer cell lines, breast cancer stem cells (CSCs) and multicellular tumor spheroids (MTSs) analyzing cell cycle, cell uptake (Nile Red-NR-) and α-tubulin expression. In addition, PLGA-PTX NPs were tested in vivo using C57BL/6 mice, including a biodistribution assay. Results: PTX-PLGA NPs induced a significant decrease in the PTX IC50 of cancer cell lines (1.31 and 3.03-fold reduction in MDA-MB-231 and E0771 cells, respectively) and CSCs. In addition, MTSs treated with PTX-PLGA exhibited a more disorganized surface and significantly higher cell death rates compared to free PTX (27.9% and 16.3% less in MTSs from MCF-7 and E0771, respectively). PTX-PLGA nanoformulation preserved PTX's mechanism of action and increased its cell internalization. Interestingly, PTX-PLGA NPs not only reduced the tumor volume of treated mice but also increased the antineoplastic drug accumulation in their lungs, liver, and spleen. In addition, mice treated with PTX-loaded NPs showed blood parameters similar to the control mice, in contrast with free PTX. Conclusion: These results suggest that our PTX-PLGA NPs could be a suitable strategy for breast cancer therapy, improving antitumor drug efficiency and reducing systemic toxicity without altering its mechanism of action.

Dextran-polylactide micelles loaded with doxorubicin and DiR for image-guided chemo-photothermal tumor therapy

Image-guided chemo-photothermal therapy based on near-infrared (NIR) theranostic agents has found promising applications in treating tumors. In this multimodal treatment, it is of critical importance to image real-time distribution of photothermal agents in vivo and to monitor therapeutic outcomes for implementing personalized treatment. In this study, an optimally synthesized dextran-polylactide (DEX-PLA) copolymer was assembled with doxorubicin (DOX) and DiR, a kind of NIR dye, to construct desirable micelles ((DiR + DOX)/DEX-PLA) for performing image-guided chemo-photothermal therapy. These (DiR + DOX)/DEX-PLA micelles had good physical and photothermal stability in aqueous media and showed high photothermal efficiency in vivo. Based on the H22-tumor-bearing mouse model, (DiR + DOX)/DEX-PLA micelles were found to accumulate inside tumors sustainably and to emit strong fluorescence signals for more than three days. The (DiR + DOX)@DEX-PLA micelles together with NIR laser irradiation were able to highly inhibit tumor growth or even eradicate tumors with one injection and two dose-designated 5-minute laser irradiations at the tumor site during 14 days of treatment. Furthermore, they showed almost no impairment to the body of the treated mice. These (DiR + DOX)@DEX-PLA micelles have confirmative translational potential in clinical tumor therapy on account of their persistent image-guided capacity, high antitumor efficacy and good in vivo safety.

Hydrophilic hindering and hydrophobic growing: a vesicle glycometabolism multi-drug combination therapeutic against Alzheimer's disease

Advanced drug vehicle exploitation and the sophisticated synergy mechanism revelation are two great difficulties in combination therapy. Compared with most readily available polymer micelles, some undiscovered complex chemical design principles limit the expanding research of polymer vesicles. Here, polycaprolactone (PCL)-g-Dextran vesicle that dextran brush steric hindrance guide PCL lamellae-aligned growth was synthesized. The effect of the glycometabolism multi-drug vesicle combination treatment and synergism mechanism were investigated on senescence-accelerated mouse prone 8 (SAMP8) mice. The main insulin sensitizer drug could improve the memory ability of mice to a small extent, and the main insulin secretion promoter drug had little beneficial effect. Moreover, the triple anti-insulin resistant drugs of insulin (INS), repaglinide (REP) and metformin hydrochloride (MET) activated the glycometabolism-related bio-signals, and the energy cycle was normalized successfully. The insulin intracellular uptake and utilization efficiency could be the reason for the gap. The upregulation of the brain-derived neurotrophic factor (BDNF) protein confirmed that the crosstalk between the mitochondria and synapse contributes to the nerve repair. This study provided an excellent drug combination vesicle to treat Alzheimer's disease (AD). The discovery of the combination mechanism leads to an improvement in the AD clinical treatment.

Endogenous Enzyme-responsive Nanoplatforms for Anti-tumor Therapy

The emergency of responsive drug delivery systems has contributed to reduced cytotoxicity, improved permeability in tissues and extended circulation time of the active drug. In particular, enzyme-responsive nanoplatforms have attracted a lot of attention due to the specificity and efficiency of an enzyme-catalyzed reaction. In this review, enzyme-based mono responsive drug delivery systems designed in the past 5 years have been summarized. These drug delivery systems were introduced by different tumor-related enzymes such as matrix metalloproteinase, esterase, hyaluronidase, caspase and cathepsin. Moreover, the enzyme-sensitive nanoplatforms activated by dual-stimuli have been also described. Although great progress had been made in the past years, the translation into clinical practice is still difficult. Thus, three obstacles (enzyme heterogeneity, reaction environment, animal model) were also discussed. In short, enzyme-activated drug delivery systems offer great potential in treating cancers.

Research progress on nanotechnology for delivery of active ingredients from traditional Chinese medicines

There is growing acceptance of traditional Chinese medicines (TCMs) as potential sources of clinical agents based on the demonstrated efficacies of numerous bioactive compounds first identified in TCM extracts, such as paclitaxel, camptothecin, and artemisinin. However, there are several challenges to achieving the full clinical potential of many TCMs, particularly the generally high hydrophobicity and low bioavailability. Recently, however, numerous studies have attempted to circumvent the limited in vivo activity and systemic toxicity of TCM ingredients by incorporation into nanoparticle-based delivery systems. Many of these formulations demonstrate improved bioavailability, enhanced tissue targeting, and greater in vivo stability compared to the native compound. This review summarizes nanoformulations of the most promising and extensively studied TCM compounds to provide a reference for further research. Combining these natural compounds with nanotechnology-based delivery systems may further improve the clinical utility of these agents, in turn leading to more intensive research on traditional medicinal compounds.

Amphiphilic copolymers in biomedical applications: Synthesis routes and property control

The request of new materials, matching strict requirements to be applied in precision and patient-specific medicine, is pushing for the synthesis of more and more complex block copolymers. Amphiphilic block copolymers are emerging in the biomedical field due to their great potential in terms of stimuli responsiveness, drug loading capabilities and reversible thermal gelation. Amphiphilicity guarantees self-assembly and thermoreversibility, while grafting polymers offers the possibility of combining blocks with various properties in one single material. These features make amphiphilic block copolymers excellent candidates for fine tuning drug delivery, gene therapy and for designing injectable hydrogels for tissue engineering. This manuscript revises the main techniques developed in the last decade for the synthesis of amphiphilic block copolymers for biomedical application. Strategies for fine tuning the properties of these novel materials during synthesis are discussed. A deep knowledge of the synthesis techniques and their effect on the performance and the biocompatibility of these polymers is the first step to move them from the lab to the bench. Current results predict a bright future for these materials in paving the way towards a smarter, less invasive, while more effective, medicine.

Hemocompatible, biocompatible and antifouling Acylated dextran-g-polytetrahydrofuran graft copolymer with silver nanoparticles: Synthesis, characterization and properties

The novel amphiphilic acylated dextran-g-polytetrahydrofuran (AcyDex-g-PTHF) graft copolymers have been successfully synthesized via combination of living cationic ring-opening polymerization of tetrahydrofuran (THF) to prepare living PTHF chains with different molecular weights (M_{n, PTHF}) of 800-2800 g/mol with nucleophile substitution to mediate grafting numbers (G_N) of 4-25 per 1000 Dex monosaccharide. The microphase separation in the graft copolymer exists for the incompatibility of hard dextran backbone and soft PTHF branches and the confined crystallization of backbone. This copolymer behaves excellent hemocompatibility with red blood cells, good biocompatibility with HeLa cells and strong resistance to bovine serum albumin adsorption. The microspheres (~1 μm) of graft copolymers loaded with drug ibuprofen exhibit pH sensitive controlled drug release behavior. Moreover, the AcyDex-g-PTHF/Ag nanocomposites show good antibacterial property against E. coli and S. aureus. This novel hemocompatible, biocompatible and antifouling AcyDex-g-PTHF graft copolymer will have potential application in biological and medical fields.

Fucoidan-based micelles as P-selectin targeted carriers for synergistic treatment of acute kidney injury

Acute kidney injury (AKI) is a life-threatening disease without effective treatment. The utilization of curcumin (Cur) for the treatment of AKI is still facing challenges due to its poor water-solubility and low bioavailability. Herein, kidney-targeted octenyl succinic anhydride-grafted fucoidan loaded with Cur (OSA-Fucoidan/Cur) was fabricated for synergistic treatment of AKI. It was found that OSA-Fucoidan/Cur micelles had a sustained drug release behavior and excellent physicochemical stability. Cellular uptake studies demonstrated that the specific binding between fucoidan and P-selectin overexpressed on H2O2-stimulated HUVECs contributed to the higher internalization of OSA-Fucoidan/Cur micelles by the cells. In addition, OSA-Fucoidan micelles exhibited an ideal kidney-targeted characteristic in lipopolysaccharide (LPS)-induced AKI mice. In vivo studies showed that the combination of Cur and OSA-Fucoidan endowed the OSA-Fucoidan/Cur micelles with synergistically anti-inflammatory and antioxidant abilities, thereby largely enhancing the therapeutic efficacy of AKI. Therefore, OSA-Fucoidan/Cur micelles may represent a potential kidney-targeted nanomedicine for effective treatment of AKI.

The Therapeutic Efficacy of Dendrimer and Micelle Formulations for Breast Cancer Treatment

Breast cancer is among the most common types of cancer in women and it is the cause of a high rate of mortality globally. The use of anticancer drugs is the standard treatment approach used for this type of cancer. However, most of these drugs are limited by multi-drug resistance, drug toxicity, poor drug bioavailability, low water solubility, poor pharmacokinetics, etc. To overcome multi-drug resistance, combinations of two or more anticancer drugs are used. However, the combination of two or more anticancer drugs produce toxic side effects. Micelles and dendrimers are promising drug delivery systems that can overcome the limitations associated with the currently used anticancer drugs. They have the capability to overcome drug resistance, reduce drug toxicity, improve the drug solubility and bioavailability. Different classes of anticancer drugs have been loaded into micelles and dendrimers, resulting in targeted drug delivery, sustained drug release mechanism, increased cellular uptake, reduced toxic side effects of the loaded drugs with enhanced anticancer activity in vitro and in vivo. This review article reports the biological outcomes of dendrimers and micelles loaded with different known anticancer agents on breast cancer in vitro and in vivo.

Fabrication and characterization of hydrocortisone loaded Dextran-Poly Lactic-co-Glycolic acid micelle

A nanomicelle based drug delivery systems is a formulation that can improve the bioavailability and dissolution rate of water-insoluble drugs. In this study, the Dextran-Poly Lactic-co-Glycolic Acid copolymer was synthesized with esterification reaction, confirmed using the fourier-transform infrared spectroscopy and nuclear magnetic resonance. The used method for nanomicelle preparation was nanoprecipitation and the critical micelle concentration value was obtained 10 μg/mL. The particle size of the nanomicelle was less than 100 nm ± 4 nm with narrow size distribution (Polydispersity index = 0.06). Hydrocortisone was loaded to this system. The obtained results for the encapsulation efficiency were 79%, and the drug release was adjusted to a first-order kinetic model with 90% release of drug within the 12 h. The MTT assay showed that even in the high concentration of micelle, the cell viability was remained higher than 90%. Considering the toxicity investigation findings, the Dextran-Poly Lactic-co-Glycolic Acid micellar systems can be suggested as a considerable drug delivery system in hydrocortisone pharmaceutical dosage forms.

Sialic acid-modified chitosan oligosaccharide-based biphasic calcium phosphate promote synergetic bone formation in rheumatoid arthritis therapy

Therapeutic goals for rheumatoid arthritis (RA) consist of inhibiting the inflammatory response and repairing the damaged bone/cartilage. Tissue engineering could achieve both goals, however, it was hindered due to the lack of biologically relevant tissue complexity, limitation in covering the entire polyarthritis lesions and requirement of extra surgical implantation. Integrating nanotechnologies into clinically sized implants represents a major opportunity to overcome these problems. Herein, we designed a sialic acid (SA)-modified chitosan oligosaccharide-based biphasic calcium phosphate (BCP), a biomimetic nanoplatform that could load with methotrexate. We found that SA modification could not only improve the accumulation of the designed organic-inorganic nanoplatform in arthritic paws (34.38% higher than those without SA modification at 48 h), but also cooperate with BCP to exert synergetic mineralization of calcium phosphate, allowing more osteoblasts to attach, proliferate and differentiate. The more differentiated osteoblasts produced 4.46-fold type I collagen and 2.60-fold osteoprotegerin compared to the control group. Besides, the disassembled nanorods released chitosan oligosaccharide-based micelles, revealing a cartilage-protective effect by reducing the loss of glycosaminoglycan. All these improvements contributed to the light inflammatory response and reduced destruction on cartilage/bone. The findings provide a novel strategy for RA therapy via nanometer-scale dimension mimicking the natural tissues.

The dextrans as vehicles for gene and drug delivery

Dextran has become a hot research topic in drug vehicle material because of its biodegradable, nonspecific cell adhesion, resistance to protein adsorption, low price and ease of structural modification. The fate and changes of dextran in vivo are not fully understood. It is helpful to guide the design and modification of dextran drug vehicles to clarify the changes in the morphology, metabolism and function of drug targets. With the deep understanding of dextran and the emergence of new functional dextran derivatives, its application in nanodrug delivery systems will be more and more, clinically applicable delivery systems may also be available.

Combinational protective therapy for spinal cord injury medicated by sialic acid-driven and polyethylene glycol based micelles

Spinal cord injury (SCI) leads to immediate disruption of neuronal membranes and loss of neurons, followed by extensive secondary injury process. Treatment of SCI still remains a tremendous challenge clinically. Minocycline could target comprehensive secondary injury via anti-inflammatory, anti-oxidant and anti-apoptotic mechanisms. Polyethylene glycol (PEG), a known sealing agent, is able to seal the damaged cell membranes and reduce calcium influx, thereby exerting neuroprotective capacity. Here, an E-selectin-targeting sialic acid - polyethylene glycol - poly (lactic-co-glycolic acid) (SAPP) copolymer was designed for delivering hydrophobic minocycline to achieve combinational therapy of SCI. The obtained SAPP copolymer could self-assemble into micelles with critical micelle concentration being of 13.40 μg/mL, and effectively encapsulate hydrophobic minocycline. The prepared drug-loaded micelles (SAPPM) displayed sustained drug release over 72 h, which could stop microglia activation and exhibited excellent neuroprotective capacity in vitro. The SAPP micelles were efficiently accumulated in the lesion site of SCI rats via the specific binding between sialic acid and E-selectin. Due to the targeting distribution and combinational effect between PEG and minocycline, SAPPM could obviously reduce the area of lesion cavity, and realize more survival of axons and myelin sheaths from the injury, thus distinctly improving hindlimb functional recovery of SCI rats and conferring superior therapeutic effect in coparison with other groups. Our work presented an effective and safe strategy for SCI targeting therapy. Besides, neuroprotective capacity of PEG deserves further investigation on other central nervous system diseases.

Application of dextran as nanoscale drug carriers

Dextran is a kind of biocompatible, nontoxic and nonimmunogenic biological substance that has been widely used in drug-delivery systems. With further research and understanding of dextran and its derivatives, people can more precisely control the sequence of dextran by chemical and biosynthetic methods as needed, and modify various structures to improve the properties of dextran, such as hydrophilicity, hydrophobicity, temperature sensitivity, pH sensitivity and ionic strength sensitivity, which will further expand the application of dextran and its derivatives in drug-delivery systems. Herein, the application of dextran and its derivatives in gene transfection and drug delivery was summarized and analyzed, and the problems were studied. At the same time, its application prospects are forecasted.

Sialic Acid-Functionalized pH-Triggered Micelles for Enhanced Tumor Tissue Accumulation and Active Cellular Internalization of Orthotopic Hepatocarcinoma

Both targeted and stimuli-sensitive drug-delivery systems (DDSs) have been developed to augment antitumor effects. However, lack of knowledge regarding tumor tissue targeting and different effects of the stimuli-sensitive DDSs in orthotropic and ectopic tumors have impeded further advances in their clinical applications. Herein, we first reported a pH-triggered micelle with sialic acid (SA)-driven targeting ability (SA-poly(ethylene glycol)-hydrazone linker-doxorubicin (DOX), SPD). The SPD micelles encapsulated with DOX (SPDD) showed sustained drug release over 48 h in response to the pH gradient in vivo, slow under physical conditions and accelerated in the acid tumor microenvironment. In addition, the SPD micelles showed 2.3-fold higher accumulation in tumors after 48 h compared to the micelles lacking the SA moiety. The overexpression of E-selectin on the inflammatory vascular endothelial cells surrounding the tumors increased the accumulation of SPD micelles in tumor tissues, whereas that on the tumor cells increased the internalization of micelles. Consequently, SPDD micelles exerted remarkable antitumor effects in both orthotopic and ectopic models. Application of SPDD micelles in the in situ model reduced the tumor volume (77.57 mm³ vs 62.13 mm³) and metastasis after treatment for 25 days. These results suggest that SA-driven targeted DDS with a pH-responsive switch has the potential to treat hepatocarcinoma effectively both ectopically and orthotopically.

Self-assembly of folic acid dextran conjugates for cancer chemotherapy

Folic acid (FA) has long been used as a specific targeting agent since many cancer cells overexpress folate receptors (FRs). Herein, novel functionalities of FA will be explored: directed self-assembly of nanoparticles for drug delivery together with pH responsive release. By conjugating with dextran (DEX), DEX-FA exerts a pH dependent self-assembly behavior: it self-associates into nanoparticles (NPs) around physiological pH (pH 7) and disassembles at higher pH (pH > 9). Doxorubicin (DOX), a model antitumor drug, has been successfully encapsulated via electrostatic interactions between DOX and FA. Moreover, the pH responsive release behaviors of DOX are controlled by FA. The DOX@DEX-FA NPs exhibit typical FA-FRs-mediated endocytosis in vitro and targeted delivery in vivo, altogether contributing to an enhanced antitumor efficacy, alleviated side effects, and elongated overall survival in a 4T1 subcutaneous tumor-bearing mouse model. The DOX@DEX-FA NPs have been demonstrated to be a simple, safe and efficient nanoplatform, holding significant translation potential for treating FR-overexpressing cancers. This study may present novel functionalities of FA in cancer-targeted nanotherapeutics.

Paclitaxel-loaded PLGA microspheres with a novel morphology to facilitate drug delivery and antitumor efficiency

A novel morphological PTX-PLGA-MS with microporous surface and porous internal structures to enhance drug loading, delivery and antitumor efficiency.

Tumor Neovasculature-Targeted APRPG-PEG-PDLLA/MPEG-PDLLA Mixed Micelle Loading Combretastatin A-4 for Breast Cancer Therapy

Breast cancer has been the first killer among women. In this study, combretastatin A-4 (CA-4) loaded 5-amino acid peptide Ala-Pro-Arg-Pro-Gly (APRPG) modified PEG-PDLLA mixed micelles was developed to target tumor neovasculature for breast cancer therapy. CA-4 is an effective vascular disrupting agent. The APRPG-modified PEG-PDLLA polymer was successfully synthesized and thin-film hydration method was used to prepare APRPG-PEG-PDLLA/MPEG-PDLLA mixed micelles. Drug loading capacity (DL), encapsulation efficiency (EE), and the optimized ratio of APRPG-PEG-PDLLA: MPEG-PDLLA for efficient drug loading was investigated. The particle size, zeta potential, morphology, and the crystallographic study were carried out to characterize the micelles. In vitro release study revealed a sustained release of CA-4 from the mixed micelles while compared to free CA-4. Moreover, the cytotoxicity data of blank and drug loaded mixed micelles suggested that the APRPG-PEG-PDLLA/MPEG-PDLLA mixed micelles were safe drug carriers and the encapsulated CA-4 remained potent antitumor effect. The cellular uptake study and the in vivo imaging and biodistribution study demonstrated that the APRPG peptide modified mixed micelles has the higher cellular uptake efficiency and could significantly facilitate the accumulation at tumor site. Furthermore, the micelles were slowly extravasated from blood vessels and inhibited embryonic angiogenesis in the transgenic zebrafish model. Consequently, the CA-4 loaded APRPG-PEG-PDLLA/MPEG-PDLLA mixed micelles group demonstrated a significant inhibition of tumor growth in 4T1 breast cancer model. In short, the CA-4 loaded APRPG-PEG-PDLLA/MPEG-PDLLA mixed micelles might have great potential for breast cancer therapy.

Improved Antitumor Efficacy of Hyaluronic Acid-Complexed Paclitaxel Nanoemulsions in Treating Non-Small Cell Lung Cancer

Paclitaxel (PTX) is a effectively chemotherapeutic agent which is extensively able to treat the non-small cell lung, pancreatic, breast and other cancers. But it is a practically insoluble drug with water solubility less than 1 μg/mL, which restricts its therapeutic application. To overcome the problem, hyaluronic acid-complexed paclitaxel nanoemulsions (HPNs) were prepared by ionic complexation of paclitaxel (PTX) nanoemulsions and hyaluronic acid (HA) to specifically target non-small cell lung cancer. HPNs were composed of dl-α-tocopheryl acetate, soybean oil, polysorbate 80, ferric chloride, and HA and fabricated by high-pressure homogenization. The HPNs were 85.2 ± 7.55 nm in diameter and had a zeta potential of −35.7 ± 0.25 mV. The encapsulation efficiency was almost 100%, and the PTX content was 3.0 mg/mL. We assessed the in vivo antitumor efficacy of the HPNs by measuring changes in tumor volume and body weight in nude mice transplanted with CD44-overexpressing NCI-H460 xenografts and treated with a bolus dose of saline, Taxol^®, PTX nanoemulsions (PNs), or HPNs at a dose of 25 mg/kg. Suppression of cancer cell growth was higher in the PN- and HPN-treated groups than in the Taxol^® group. In particular, HPN treatment dramatically inhibited tumor growth, likely because of the specific tumor-targeting affinity of HA for CD44-overexpressed cancer cells. The loss of body weight and organ weight did not vary significantly between the groups. It is suggest that HPNs should be used to effective nanocarrier system for targeting delivery of non-small cell lung cancer overexpressing CD44 and high solubilization of poorly soluble drug.

Simultaneous quantitative analysis of polyethylene glycol (PEG), PEGylated paclitaxel and paclitaxel in rats by MS/MSALL technique with hybrid quadrupole time-of-flight mass spectrometry

PEGylation is practically one of most important modifications of drugs including small molecules, peptides and proteins, which has been proven to dramatically improve physicochemical properties and pharmacokinetic behavior of the PEGylated drugs. However, it is a challenge currently to quantitatively analyze PEG and PEGylated drugs by various analytical methods, even mass spectrometry because of multiple parent ion distribution of PEG caused by its polydispersity of molecular weight. Here we developed a robust method with MS/MS^ALL technique using electrospray ionization (ESI) source coupled high resolution Quadrupole Time-of-Flight (Q-TOF) mass spectrometry for the quantification of PEG2K-Paclitaxel (PEG-PTX) and its two metabolites, PEG and Paclitaxel (PTX). The analysis was performed on a 300SB-C18 column with acetonitrile and 0.1% formic acid as the mobile phase. Samples were simply prepared by protein precipitation in a small quantity of plasma (50μL). Calibration curve was linear within the range of 50.0-4000ng/mL for PEG and PEG-PTX and 1.0-1000ng/mL for PTX. The intra- and inter-day precisions were 3.2-6.9% and 3.1-6.9% for PEG, 4.1-7.8% and 4.0-9.9% for PEG-PTX, and 3.3-4.8% and 3.1-6.9% for PTX, respectively. The recoveries were greater than 90% with low matrix effects. Afterwards, the newly developed method was successfully applied to support a preclinical pharmacokinetic study in six rats after single intravenous injection of PEG-PTX (51.7mg/kg).

E-selectin-targeted Sialic Acid-PEG-dexamethasone Micelles for Enhanced Anti-Inflammatory Efficacy for Acute Kidney Injury

The effective treatment for acute kidney injury (AKI) is currently limited, and care is primarily supportive. Sialic acid (SA) is main component of Sialyl Lewisx antigen on the mammalian cell surface, which participates in E-selectin binding. Therefore, dexamethasone(DXM)-loaded E-selectin-targeting sialic acid-polyethylene glycol-dexamethasone (SA-PEG-DXM/DXM) conjugate micelles are designed for ameliorating AKI. The conjugates are synthesized via the esterification reaction between PEG and SA or DXM, and can spontaneously form micelles in an aqueous solution with a 65.6 µg/mL critical micelle concentration. Free DXM is incorporated into the micelles with 6.28 ± 0.21% drug loading content. In vitro DXM release from SA-PEG-DXM/DXM micelles can be prolonged to 48h. Much more SA-PEG-DXM micelles can be internalized by lipopolysaccharide (LPS)-activated human umbilical vein endothelial cells (HUVECs) in comparison to PEG-DXM micelles due to specific interaction between SA and E-selectin expressed on HUVECs, and consequently more SA-PEG-DXM micelles are accumulated in the kidney of AKI murine model. Furthermore, SA in SA-PEG-DXM conjugates can significantly ameliorate LPS-induced production of pro-inflammatory cytokines via suppressing LPS-activated Beclin-1/Atg5-Atg12-mediated autophagy to attenuate toxicity. Compared with free DXM and PEG-DXM/DXM micelles, SA-PEG-DXM/DXM micelles show better therapeutical effects, as reflected by the improved renal function, histopathological changes, pro-inflammatory cytokines, oxidative stress and expression of apoptotic related proteins.

Novel Poly(Diol Sebacate)s as Additives to Modify Paclitaxel Release From Poly(Lactic-co-Glycolic Acid) Thin Films

Paclitaxel (PTX) incorporation in poly(lactic-co-glycolic acid) (PLGA) matrices produce films with high tensile rigidity and slow release that fail to deliver the required release rate for most biomedical applications such as in drug eluting stents and cancer treatments. To modify and improve this behavior, a set of poly(diol sebacate)s were synthesized and fully characterized as possible additives. The tensile properties of PLGA blends were evaluated as these materials could be used as coatings in drug eluting stent applications. A significant improvement in mechanical flexibility was observed with 20% additive content, as it reduced the Young's modulus value and increased the maximum deformation at break. PTX release was studied and correlated with the release of additive from PLGA films. An increase in the initial burst release phase was observed on all blends when compared to the control films of PLGA. Modulation of PTX release was achieved by altering the hydrophilicity degree of the additive or its percentage content on the blend. This supports the possibility that PTX was partitioned into the additive phase. Cytotoxicity analyses of novel additives were performed on mouse embryonic fibroblasts NIH/3T3.

Self-assembled liposomes of dual paclitaxel-phospholipid prodrug for anticancer therapy

In this report, a newly liposomal formulation of paclitaxel (PTX) based on dual paclitaxel succinate glycerophosphorylcholine (Di-PTX-GPC) prodrug was developed. The Di-PTX-GPC prodrug was synthesized by conjugating PTX with GPC through esterification under N,N'-carbonyldiimidazole (CDI) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) catalytic system. Di-PTX-GPC liposomes were prepared by thin film method and characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). The results indicated that the liposomes have an average diameter of 157.9nm with well-defined spherical morphology. In vitro drug release studies confirmed that the Di-PTX-GPC liposomes have controlled release profile of PTX at a weakly acidic environment, which formulates them suitable for sustained drug delivery. Additionally, in vitro cellular uptake analysis and cytotoxicity evaluation showed that Di-PTX-GPC liposomes were internalized successfully into tumor cells to induce the apoptosis against MCF-7, HeLa and HepG-2 cells. In vivo pharmacokinetics study revealed that such liposomal formulation of Di-PTX-GPC has longer retention half-life in bloodstream, which subsequently leads to slight accumulate in tumor sites due to enhanced permeability and retention (EPR) effect. More importantly, Di-PTX-GPC liposomes demonstrated good in vivo anticancer activities compared to Taxol with reduced adverse effects. Conclusively, these results suggest that Di-PTX-GPC liposomes could be an effective PTX delivery vehicles in clinical cancer chemotherapy.

Novel Nano-Therapeutic Approach Actively Targets Human Ovarian Cancer Stem Cells after Xenograft into Nude Mice

The power of tumorigenesis, chemo-resistance and metastasis in malignant ovarian tumors resides in a tiny population of cancer cells known as ovarian cancer stem cells (OCSCs). Developing nano-therapeutic targeting of OCSCs is considered a great challenge. The potential use of poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) was investigated as a drug delivery system for paclitaxel (PTX) against OCSCs in vitro and in vivo. PTX-loaded PLGA NPs were prepared by an emulsion solvent evaporation method, supported by incorporation of folic acid (FA) as the ligand. NPs were characterized for size, surface morphology, drug loading, and encapsulation efficiency. In vitro cytotoxicity of PTX-loaded FA/PLGA NPs was tested against OCSCs with MTT assay. In vivo anti-tumoral efficiency and active targeting potential of prepared NPs against tumors in nude mice were investigated. In vitro results revealed that IC₅₀ of PTX was significantly reduced after loading on PLGA NPs. On the other hand, in vivo results showed that PLGA NPs enhanced the tumor suppression efficiency of PTX. Investigation with real time quantitative PCR analysis revealed the limiting expression of chemo-resistant genes (ABCG2 and MDR1) after applying PLGA NPs as a drug delivery system for PTX. Histopathological examination of tumors showed the effective biological influence of PTX-loaded FA/PLGA NPs through the appearance of reactive lymphoid follicles. Targeting potential of PTX was activated by FA/PLGA NPs through significant preservation of body weight (p < 0.0001) and minimizing the systemic toxicity in healthy tissues. Immunohistochemical investigation revealed a high expression of apoptotic markers in tumor tissue, supporting the targeting effect of FA/PLGA NPs. A drug delivery system based on FA/PLGA NPs can enhance PTX’s in vitro cytotoxicity and in vivo targeting potential against OCSCs.

Enhancing Doxorubicin Delivery toward Tumor by Hydroxyethyl Starch-g-Polylactide Partner Nanocarriers

Doxorubicin (DOX), a kind of wide-spectrum chemotherapeutic drug, can cause severe side effects in clinical use. To enhance its antitumor efficacy while reducing the side effects, two kinds of nanoparticles with desirable compositions and properties were assembled using optimally synthesized hydroxyethyl starch-grafted-polylactide (HES-g-PLA) copolymers and utilized as partner nanocarriers. The large empty HES-g-PLA nanoparticles (mean size, ca. 700 nm), at an optimized dose of 400 mg/kg, were used to block up the reticuloendothelial system in tumor-bearing mice 1.5 h in advance, and the small DOX-loaded HES-g-PLA nanoparticles (mean size, ca. 130 nm) were subsequently applied to the mice. When these partner nanocarriers were administered in this sequential mode, the released DOX had a significantly prolonged plasma half-life time and much slower clearance rate as well as a largely enhanced intratumoral accumulation as compared to free DOX. In vivo antitumor studies demonstrated that the DOX-loaded HES-g-PLA nanoparticles working together with their partner exhibited remarkably enhanced antitumor efficacy in comparison to free DOX. In addition, these HES-g-PLA partner nanocarriers showed negligible damage to the normal organs of the treated mice. Considering safe and efficient antitumor performance of DOX-loaded HES-g-PLA nanoparticles, the newly developed partner nanocarriers in combination with their administration mode have promising potential in clinical cancer chemotherapy.

Systematic evaluation of multifunctional paclitaxel-loaded polymeric mixed micelles as a potential anticancer remedy to overcome multidrug resistance

Multidrug resistance (MDR) of tumor cells is becoming the main reason for the failure of chemotherapy and P-glycoprotein (P-gp) mediated drug efflux has demonstrated to be the key factor for MDR. To address this issue, a novel pH-responsive mixed micelles drug delivery system composed of dextran-g-poly(lactide-co-glycolide)-g-histidine (HDP) and folate acid-D-α-tocopheryl polyethylene glycol 2000 (FA-TPGS2K) copolymers has been designed for the delivery of antitumor agent, paclitaxel (PTX) via FA-receptor mediated cell endocytosis, into PTX-resistant breast cancer MCF-7 cells (MCF-7/PTX). PTX-loaded FA-TPGS2K/HDP mixed micelles were characterized to have a small size distribution, high loading content and excellent pH-responsive drug release profiles. Compared with HDP micelles, FA-TPGS2K/HDP mixed micelles showed a higher cytotoxicity against MCF-7 and MCF-7/PTX cells due to the synergistic effect of FA-receptor mediated cell endocytosis, pH-responsive drug release and TPGS mediated P-gp inhibition. P-gp expression level, ATP content and mitochondrial membrane potential change have been measured, the results indicated blank FA-TPGS2K/HDP mixed micelles could inhibit the P-gp activity by reducing the mitochondrial membrane potential and depleting ATP content but not down-regulating the P-gp expression. In vivo antitumor activities demonstrated FA-TPGS2K/HDP mixed micelles could reach higher antitumor activity compared with HDP micelles for MCF-7/PTX tumor cells. Histological assay also indicated that FA-TPGS2K/HDP mixed micelles showed strongly apoptosis inducing effect, anti-proliferation effect and anti-angiogenesis effect. All these evidences demonstrated this pH-sensitive FA-TPGS2K/HDP micelle-based drug delivery system is a promising approach for overcoming MDR.

STATEMENT OF SIGNIFICANCE

In this work, a novel FA-TPGS2K copolymer has been synthesized and used it to construct mixed micelles with HDP copolymer to overcome MDR effect. Furthermore, a series in vitro and in vivo evaluations have been made, which supported enough evidences for the efficient delivery of antitumor drug to MDR cells.

Paclitaxel-loaded hyaluronan solid nanoemulsions for enhanced treatment efficacy in ovarian cancer

Paclitaxel-loaded hyaluronan solid nanoemulsions (PTX-HSNs) were successfully fabricated for the delivery of PTX to improve ovarian cancer treatment via active tumor targeting. PTX-HSNs were fabricated using high-pressure homogenization with a microfluidizer and were lyophilized with d-mannitol. Hyaluronan was coated on the outside of the PTX-HSN sphere. The mean size of the PTX-HSNs was maintained less than 100 nm, with a relatively narrow size distribution. The PTX loading content was 3 mg/mL, and encapsulation efficiency (EE) was close to 100%. In vitro cell affinity studies using SK-OV-3 (cluster of differentiation 44 [CD44⁺]) and OVCAR-3 (CD44⁻) cells showed that PTX-HSN had a targeting capability hundredfold higher than that of PTX-loaded solid nanoemulsions (PTX-SNs) without hyaluronan. Further, the in vitro PTX release by PTX-SNs and PTX-HSNs lasted more than 6 days without showing a release burst, which was more sustained than that of Taxol^®, suggesting a more constant effect on cancer cells at the tumor site than was observed for Taxol. The in vivo toxicity, in vivo antitumor effects, and pharmacokinetics of PTX-HSNs and Taxol were evaluated in nude mice and rats. The maximum tolerated dose (MTD) for PTX-HSNs, PTX-SNs, and Taxol was determined by measuring changes in clinical symptoms after administering 20–50 mg/kg PTX via the caudal vein. The MTD of PTX-HSNs had a dosing capacity greater than 50 mg PTX/kg, which was 2.5-fold higher than that of Taxol when administered as a PTX injection. In vivo, PTX-HSN treatment effectively inhibited tumor growth and showed less toxicity in tumor-transplanted mice compared to that observed for Taxol treatments. The pharmacokinetic parameters of PTX-HSNs were more desirable than those of Taxol. After PTX-HSN treatment, the circulation time of PTX was prolonged and retention of PTX in ovarian tumor tissues increased. Therefore, PTX-HSN is a highly effective nanosystem with a high MTD for delivering PTX to ovarian cancers characterized by CD44 overexpression, enhanced active tumor targeting, and low toxicity.

Endogenous Polysialic Acid Based Micelles for Calmodulin Antagonist Delivery against Vascular Dementia

Clinical treatment for vascular dementia still remains a challenge mainly due to the blood-brain barrier (BBB). Here, a micelle based on polysialic acid (PSA), which is a hydrophilic and endogenous carbohydrate polymer, was designed to deliver calmodulin antagonist for therapy of vascular dementia. PSA was first chemically conjugated with octadecylamine (ODA), and the obtained PSA-ODA copolymer could self-assemble into micelle in aqueous solution with a 120.0 μg/mL critical micelle concentration. The calmodulin antagonist loaded PSA-ODA micelle, featuring sustained drug release behavior over a period of 72 h with a 3.6% (w/w) drug content and a 107.0 ± 4.0 nm size was then fabricated. The PSA-ODA micelle could cross the BBB mainly via active endocytosis by brain endothelial cells followed by transcytosis. In a water maze test for spatial learning, calmodulin antagonist loaded PSA-ODA micelle significantly reduced the escape latencies of right unilateral common carotid arteries occlusion (rUCCAO) mice with dosage significantly reduced versus free drug. The decrease of hippocampal phospho-CaMKII (Thr286/287) and phospho-synapsin I (Ser603) was partially restored in rUCCAO mice following calmodulin antagonist loaded PSA-ODA micelle treatment. Consistent with the restored CaMKII phosphorylation, the elevation of BrdU/NeuN double-positive cells in the same context was also observed. Overall, the PSA-ODA micelle developed from the endogenous material might promote the development of therapeutic approaches for improving the efficacy of brain-targeted drug delivery and have great potential for vascular dementia treatment.

Carbohydrate-based amphiphilic nano delivery systems for cancer therapy

Nanoparticles (NPs) are novel drug delivery systems that have been attracting more and more attention in recent years, and have been used for the treatment of cancer, infection, inflammation and other diseases. Among the numerous classes of materials employed for constructing NPs, organic polymers are outstanding due to the flexibility of design and synthesis and the ease of modification and functionalization. In particular, NP based amphiphilic polymers make a great contribution to the delivery of poorly-water soluble drugs. For example, natural, biocompatible and biodegradable products like polysaccharides are widely used as building blocks for the preparation of such drug delivery vehicles. This review will detail carbohydrate based amphiphilic polymeric systems for cancer therapy. Specifically, it focuses on the nature of the polymer employed for the preparation of targeted nanocarriers, the synthetic methods, as well as strategies for the application and evaluation of biological activity. Applications of the amphiphilic polymer systems include drug delivery, gene delivery, photosensitizer delivery, diagnostic imaging and specific ligand-assisted cellular uptake. As a result, a thorough understanding of the relationship between chemical structure and biological properties facilitate the optimal design and rational clinical application of the resulting carbohydrate based nano delivery systems for cancer therapy.

A novel cabazitaxel-loaded polymeric micelle system with superior in vitro stability and long blood circulation time

Cabazitaxel (CTX) is a second-generation semisynthetic taxane that demonstrates antitumor activity superior to docetaxel. However, the low aqueous solubility of CTX has hampered its use as a therapeutic agent. In this work, CTX-loaded N-t-butoxycarbonyl-L-phenylalanine end-capped monomethyl poly (ethylene glycol)-block-poly (D,L-lactide) (mPEG-PLA-Phe(Boc)/CTX) micelles were prepared to improve the solubility of CTX while retaining its superior stability before accessing the tumor site. The mPEG-PLA-Phe(Boc)/CTX micelles showed excellent stability in vitro compared with mPEG-PLA/CTX micelles. When stored at 25 °C, the mPEG-PLA/CTX micelles tended to aggregate within 1 h, whereas the mPEG-PLA-Phe(Boc)/CTX micelles were uniformly transparent even after three weeks. Dilution of mPEG-PLA/CTX micelles widened their size distribution and decreased the encapsulation efficiency, while significant change was not found in mPEG-PLA-Phe(Boc)/CTX micelles, even when diluted 1000-fold. Pharmacokinetic results in Sprague-Dawley rats indicated that, compared with Jevtana(®), intravenous administration of mPEG-PLA-Phe(Boc)/CTX micelles stably retained the CTX in plasma with 26.03-fold larger of the area under the time-concentration curve, 2.13-fold longer of the half-life, and 9.99-fold higher of the maximum concentration. In conclusion, mPEG-PLA-Phe(Boc) micelle may be a potential nanocarrier not only to improve the solubility of CTX but also to prolong the blood circulation time, which results in improved biological activity.

How can nanomedicines overcome cellular-based anticancer drug resistance?

This review discusses the mechanisms of anticancer drug resistance according to its cellular level of action and outlines the nanomedicine-based strategies adopted to overcome it.

Self-assembly of pH-responsive dextran-g-poly(lactide-co-glycolide)-g-histidine copolymer micelles for intracellular delivery of paclitaxel and its antitumor activity

Herein, dextran (DX) was conjugated with poly(lactide-co-glycolide) (PLGA) and histidine (His) to prepare a pH-responsive nanocarrier, dextran-g-poly(lactide-co-glycolide)-g-histidine (HDP) micelles, for the delivery of antitumor drugs.

Development of Alendronate-conjugated Poly (lactic-co-glycolic acid)-Dextran Nanoparticles for Active Targeting of Cisplatin in Osteosarcoma

In this study, we developed a novel poly (lactic-co-glycolic acid)-dextran (PLD)-based nanodelivery system to enhance the anticancer potential of cisplatin (CDDP) in osteosarcoma cells. A nanosized CDDP-loaded PLGA-DX nanoparticle (PLD/CDDP) controlled the release rate of CDDP up to 48 h. In vitro cytotoxicity assay showed a superior anticancer effect for PLD/CDDP and with an appreciable cellular uptake via endocytosis-mediated pathways. PLD/CDDP exhibited significant apoptosis of MG63 cancer cells compared to that of free CDDP. Approximately ~25% of cells were in early apoptosis phase after PLD/CDDP treatment comparing to ~15% for free CDDP after 48h incubation. Similarly, PLD/CDDP exhibited ~30% of late apoptosis cells comparing to only ~8% for free drug treatment. PLD/CDDP exhibited significantly higher G2/M phase arrest in MG63 cells than compared to free CDDP with a nearly 2-fold higher arrest in case of PLD/CDDP treated group (~60%). Importantly, PLD/CDDP exhibited a most significant anti-tumor activity with maximum tumor growth inhibition. The superior inhibitory effect was further confirmed by a marked reduction in the number of CD31 stained tumor blood vessels and decrease in the Ki67 staining intensity for PLD/CDDP treated animal group. Overall, CDDP formulations could provide a promising and most effective platform in the treatment of osteosarcoma.