In vitro and in vivo evaluation of actively targetable nanoparticles for paclitaxel delivery

Multifunctional Liposomes Co-Modified with Ginsenoside Compound K and Hyaluronic Acid for Tumor-Targeted Therapy

Liposomes show promise for anti-cancer drug delivery and tumor-targeted therapy. However, complex tumor microenvironments and the performance limitations of traditional liposomes restrict clinical translation. Hyaluronic acid (HA)-modified nanoliposomes effectively target CD44-overexpressing tumor cells. Combination therapy enhances treatment efficacy and delays drug resistance. Here, we developed paclitaxel (PTX) liposomes co-modified with ginsenoside compound K (CK) and HA using film dispersion. Compared to cholesterol (Ch), CK substantially improved encapsulation efficiency and stability. In vitro release studies revealed pH-responsive behavior, with slower release at pH 7.4 versus faster release at pH 5. In vitro cytotoxicity assays demonstrated that replacing Ch with CK in modified liposomes considerably decreased HCT-116 cell viability. Furthermore, flow cytometry and fluorescence microscopy showed a higher cellular uptake of PTX-CK-Lip-HA in CD44-high cells, reflected in the lower half maximal inhibitory concentrations. Overall, CK/HA-modified liposomes represent an innovative, targeted delivery system for enhanced tumor therapy via pH-triggered drug release and CD44 binding.

Localized chemotherapy approaches and advanced drug delivery strategies: a step forward in the treatment of peritoneal carcinomatosis from ovarian cancer

Peritoneal carcinomatosis (PC) is a common outcome of epithelial ovarian carcinoma and is the leading cause of death for these patients. Tumor location, extent, peculiarities of the microenvironment, and the development of drug resistance are the main challenges that need to be addressed to improve therapeutic outcome. The development of new procedures such as HIPEC (Hyperthermic Intraperitoneal Chemotherapy) and PIPAC (Pressurized Intraperitoneal Aerosol Chemotherapy) have enabled locoregional delivery of chemotherapeutics, while the increasingly efficient design and development of advanced drug delivery micro and nanosystems are helping to promote tumor targeting and penetration and to reduce the side effects associated with systemic chemotherapy administration. The possibility of combining drug-loaded carriers with delivery via HIPEC and PIPAC represents a powerful tool to improve treatment efficacy, and this possibility has recently begun to be explored. This review will discuss the latest advances in the treatment of PC derived from ovarian cancer, with a focus on the potential of PIPAC and nanoparticles in terms of their application to develop new therapeutic strategies and future prospects.

Transferrin receptor-mediated liposomal drug delivery: recent trends in targeted therapy of cancer

INTRODUCTION

Compared to normal cells, malignant cancer cells require more iron for their growth and rapid proliferation, which can be supplied by a high expression level of transferrin receptor (TfR). It is well known that the expression of TfR on the tumor cells is considerably higher than that of normal cells, which makes TfR an attractive target in cancer therapy.

AREAS COVERED

In this review, the primary focus is on the role of TfR as a valuable tool for cancer-targeted drug delivery, followed by the full coverage of available TfR ligands and their conjugation chemistry to the surface of liposomes. Finally, the most recent studies investigating the potential of TfR-targeted liposomes as promising drug delivery vehicles to different cancer cells are highlighted with emphasis on their improvement possibilities to become a part of future cancer medicines.

EXPERT OPINION

Liposomes as a valuable class of nanocarriers have gained much attention toward cancer therapy. From all the studies that have exploited the therapeutic and diagnostic potential of TfR on cancer cells, it can be realized that the systematic assessment of TfR ligands applied for liposomal targeted delivery has yet to be entirely accomplished.

Design and Characterization of Paclitaxel-Loaded Polymeric Nanoparticles Decorated With Trastuzumab for the Effective Treatment of Breast Cancer

The aim of the study was to design and formulate an antibody-mediated targeted, biodegradable polymeric drug delivery system releasing drug in a controlled manner to achieve a therapeutic goal for the effective treatment of breast cancer. Antibody-mediated paclitaxel-loaded PLGA polymeric nanoformulations were prepared by the solvent evaporation method using different experimental parameters and compatibility studies. The optimized formulations were selected for in vitro and in vivo evaluation and cytotoxicity studies. The in vitro drug release studies show a biphasic release pattern for the paclitaxel-loaded PLGA nanoparticles showing a burst release for 24 h followed by an extended release for 14 days; however, a more controlled and sustained release was observed for antibody-conjugated polymeric nanoparticles. The cytotoxicity of reference drug and paclitaxel-loaded PLGA nanoparticles with and without antibody was determined by performing MTT assay against MCF-7 cells. Rabbits were used as experimental animals for the assessment of various in vivo pharmacokinetic parameters of selected formulations. The pharmacokinetic parameters such as C_max (1.18–1.33 folds), AUC_0-t (39.38–46.55 folds), MRT (10.04–12.79 folds), t_1/2 (3.06–4.6 folds), and V_d (6.96–8.38 folds) have been increased significantly while clearance (4.34–4.61 folds) has been decreased significantly for the selected nanoformulations as compared to commercially available paclitaxel formulation (Paclixil^®). The surface conjugation of nanoparticles with trastuzumab resulted in an increase in in vitro cytotoxicity as compared to plain nanoformulations and commercially available conventional brand (Paclixil^®). The developed PLGA-paclitaxel nanoformulations conjugated with trastuzumab have the desired physiochemical characteristics, surface morphology, sustained release kinetics, and enhanced targeting.

Mangiferin: a review of dietary sources, absorption, metabolism, bioavailability, and safety

Mangiferin is a potential candidate for use in nutraceutical and functional food applications due to its numerous bioactivities. However, the low bioavailability of mangiferin is a major limitation for establishing efficacy for use. This review describes current information on known food sources and factors that influence mangiferin contents, absorption, and metabolism features, and recent progress that has come from research efforts to increase the bioavailability of mangiferin. We also list patents that targeted to enhance mangiferin bioavailability. Mangifera indica L. is the major dietary source for mangiferin, a xanthone that varies widely in different parts of the plant and is influenced by many factors that involve plant propagation and post-harvest processing. Mangiferin absorption occurs mostly in the small intestine by passive diffusion with varying absorption capacities in different segments of the gastrointestinal tract. Recent research has led to the development of novel technologies to encapsulate mangiferin in nano/microparticle carrier systems as well as generate mangiferin derivatives to improve solubility and bioavailability. Preclinical studies reported that mangiferin < 2000 mg/kg is generally nontoxic. The safety and the increase in bioavailability are key limiting factors for developing successful applications for mangiferin as a nutritional dietary supplement or nutraceutical.

Improving the bioavailability and bioactivity of garlic bioactive compounds via nanotechnology

This review highlights main bioactive compounds and important biological functions especially anticancer effects of the garlic. In addition, we review current literature on the stability and bioavailability of garlic components. Finally, this review aims to provide a potential strategy for using nanotechnology to increase the stability and solubility of garlic components, providing guidelines for the qualities of garlic products to improve their absorption and prevent their early degradation, and extend their circulation time in the body. The application of nanotechnology to improve the bioavailability and targeting of garlic compounds are expected to provide a theoretical basis for the functional components of garlic to treat human health. We review the improvement of bioavailability and bioactivity of garlic bioactive compounds via nanotechnology, which could promisingly overcome the limitations of conventional garlic products, and would be used to prevent and treat cancer and other diseases in the near future.

The Use of Alternative Strategies for Enhanced Nanoparticle Delivery to Solid Tumors

Nanomaterial (NM) delivery to solid tumors has been the focus of intense research for over a decade. Classically, scientists have tried to improve NM delivery by employing passive or active targeting strategies, making use of the so-called enhanced permeability and retention (EPR) effect. This phenomenon is made possible due to the leaky tumor vasculature through which NMs can leave the bloodstream, traverse through the gaps in the endothelial lining of the vessels, and enter the tumor. Recent studies have shown that despite many efforts to employ the EPR effect, this process remains very poor. Furthermore, the role of the EPR effect has been called into question, where it has been suggested that NMs enter the tumor via active mechanisms and not through the endothelial gaps. In this review, we provide a short overview of the EPR and mechanisms to enhance it, after which we focus on alternative delivery strategies that do not solely rely on EPR in itself but can offer interesting pharmacological, physical, and biological solutions for enhanced delivery. We discuss the strengths and shortcomings of these different strategies and suggest combinatorial approaches as the ideal path forward.

Combination immunotherapy of oncolytic virus nanovesicles and PD-1 blockade effectively enhances therapeutic effects and boosts antitumour immune response

Immunotherapies are changing the landscape of melanoma treatment, but 70% of the melanoma patients have no response to immune checkpoint inhibitors or oncolytic virus therapy. Thus, novel formulations are needed to improve the population benefiting from immunotherapy. Here, we report a combined therapeutic modality based on oncolytic virus nanovesicles composed of CaCl₂, oncolytic virus Ad5, lecithin and cholesterol (Lipo-Cap-Ad5) with immune checkpoint blockade (anti-PD-1 antibody). We investigated in vivo antitumour activity, systemic toxicity and mechanism of antitumour immune responses of Lipo-Cap-Ad5 + anti-PD-1 blockade, in a murine B16F10 tumour xenograft model. Through a series of in vivo studies, we found that Lipo-Cap-Ad5 in combination with anti-PD-1 blockade drastically reduced the tumour growth by 76.6%, and prolonged animals' survival with no obvious toxicity observed in heart, liver and kidney. The combination therapy facilitates tumour infiltration of effector CD4⁺, CD8⁺ T cells and increases secretion of TNF-α and IFN-γ. Therefore, Lipo-Cap-Ad5 in combination with anti-PD-1 blockade can potentiate and activate the immune system synergistically, ultimately creating a pro-inflammatory environment. These results suggest that combination immunotherapy of Lipo-Cap-Ad5 and anti-PD-1 blockade developed in this study has promising applications to enhance therapeutic efficacy with the potential of being translated into clinical practice.

Cyclic β-(1, 2)-glucan blended poly DL lactic co glycolic acid (PLGA 10:90) nanoparticles for drug delivery

Our group had previously reported the encapsulation efficiency of cyclic β-(1, 2)-glucan for various drugs. The current study is aimed at evaluating the use of glucan as a drug carrier system by blending with poly lactic-co- glycolic acid (L:G = 10:90). Nanoparticles of glucan (0.5, 5, 10 and 20 wt %) blended with PLGA and gentamicin were synthesized. Encapsulation efficiency was higher for the blends (93% with 20 wt % of glucan) than the PLGA alone (79.8%). The presence of glucan enhanced both the biodegradability, and biocompatibility of PLGA. Degradation of the nanoparticles in vitro, was autocatalytic with an initial burst release of active drug and the release profile was modeled using the Korsmeyer-Peppas scheme. In vivo studies indicated that the drug released from the blends had high volume of distribution, and greater clearance from the system. Pharmacokinetics of the drug was predicted using a double exponential decay model. Blending with PLGA improved the drug release characteristics of the cyclic β-(1, 2)-glucan.

Polymeric nanogels as drug delivery systems

The present review focuses on the description of the design, synthesis and physico-chemical and biological evaluation of polymer nanogels. Nanogels are robust swollen cross-linked polymer nanoparticles that can be used as highly efficient and biodegradable carriers for the transport of drugs in controlled drug delivery. In this article, various types of nanogels are described and methods for their preparation discussed. The possibility of using synthesized nanosystems for targeting are reviewed to show the potential of tailored structures to reach either solid tumor tissue or direct tumor cells. Finally, the methods for encapsulation or attachment of biologically active molecules, e.g. drugs, proteins, are described and compared.

The treatment value of IL-1β monoclonal antibody under the targeting location of alpha-methyl-L-tryptophan and superparamagnetic iron oxide nanoparticles in an acute temporal lobe epilepsy model

BACKGROUND

Temporal lobe epilepsy (TLE) is a common and often refractory brain disease that is closely correlated with inflammation. Alpha-methyl-L-tryptophan (AMT) is recognized as a surrogate marker for epilepsy, characterized by high uptake in the epileptic focus. There are many advantages of using the magnetic targeting drug delivery system of superparamagnetic iron oxide nanoparticles (SPIONs) to treat many diseases, including epilepsy. We hypothesized that AMT and an IL-1β monoclonal antibody (anti-IL-1β mAb) chelated to SPIONs would utilize the unique advantages of SPIONs and AMT to deliver the anti-IL-1β mAb across the blood-brain barrier (BBB) as a targeted therapy.

METHODS

Acute TLE was induced in 30 rats via treatment with lithium-chloride pilocarpine. The effects of plain-SPIONs, anti-IL-1β-mAb-SPIONs, or AMT-anti-IL-1β-mAb-SPIONs on seizure onset were assessed 48 h later. Perl's iron staining, Nissl staining, immunofluorescence staining and western blotting were performed after magnetic resonance imaging examination.

RESULTS

The imaging and histopathology in combination with the molecular biology findings showed that AMT-anti-IL-1β-mAb-SPIONs were more likely to penetrate the BBB in the acute TLE model to reach the targeting location and deliver a therapeutic effect than plain-SPIONs and anti-IL-1β-mAb-SPIONs.

CONCLUSIONS

This study demonstrated the significance of anti-IL-1β-mAb treatment in acute TLE with respect to the unique advantages of SPIONs and the active location-targeting characteristic of AMT.

Lipid‐enveloped PLGA as a hybrid carrier for sustained delivering camptothecin in ovarian cancer

Camptothecin (CPT) is plant alkaloid exhibiting in a wide range of solid tumours. However, CPT was instability at physiological pH conditions, the lactone moieties easily hydrolysed makes systemic toxicity risky. Moreover, the water insolubility of CPT was obstructed in clinical development. The aim of the study was to utilise nontoxic and biodegradable poly(D,L‐lactic‐co‐glycolic acid) (PLGA) incorporated lipid as a hybrid nanoparticle (lipid‐PLGA NPs) for delivery of CPT. Lipid‐PLGA NPs were produced by a nano‐precipitation technique. The optimal formulation was presented that particles of which were 43 nm in diameter, with a polydispersity index of 0.3 which indicated a smaller and well‐distributed pattern. Moreover, a high capacity of ∼95% entrapment efficiency was achieved. An in vitro release study showed that non‐formulated CPT with a lag time of ∼0 h, demonstrated an obvious burst effect; in contrast, sustained released and a lag time delay were clearly observed in lipid‐PLGA NPs. The cytotoxicity study confirmed that human ovarian cancer cells (ES‐2) were inhibited by lipid‐PLGA NPs. CPT was successful entrapped in lipid‐PLGA NPs which achieved smaller size and well distribution. Lipid‐PLGA NPs resolve the water insolubility and produced a sustained, slow‐release pattern of CPT and controlled the cytotoxicity toward ES‐2.

Poly-epsilon-caprolactone nanoparticles enhance ursolic acid in vivo efficacy against Trypanosoma cruzi infection

Despite affecting millions of people worldwide, Chagas disease is still neglected by the academia and industry and the therapeutic option available, benznidazole, presents limited efficacy and side effects. Within this context, ursolic acid may serve as an option for treatment, however has low bioavailability, which can be enhanced through the encapsulation in polymeric nanoparticles. Therefore, herein we developed ursolic acid-loaded nanoparticles with poly-ε-caprolactone by the nanoprecipitation method and characterized them for particle size, zeta potential, polydispersity, encapsulation efficiency, morphology by scanning electron microscopy and thermal behavior by differential scanning calorimetry. Results indicated that an appropriate ratio of organic phase/aqueous phase and polymer/drug is necessary to produce smaller particles, with low polydispersity, negative zeta potential and high drug encapsulation efficiency. In vitro studies indicated the safety of the formulation against fibroblast culture and its efficacy in killing T. cruzi. Very importantly, the in vivo study revealed that the ursolic acid-loaded nanoparticle is as potent as the benznidazole group to control parasitemia, which could be attributed to improved bioavailability of the encapsulated drug. Finally, the toxicity evaluation showed that while benznidazole group caused liver toxicity, the nanoparticles were safe, indicating that this formulation is promising for future evaluation.

Engineered Hydrogels in Cancer Therapy and Diagnosis

Over the last decade, numerous investigations have attempted to clarify the intricacies of tumor development to propose effective approaches for cancer treatment. Thanks to the unique properties of hydrogels, researchers have made significant progress in tumor model reconstruction, tumor diagnosis, and associated therapies. Notably, hydrogel-based systems can be adjusted to respond to cancer-specific hallmarks and/or external stimuli. These well-known drug reservoirs can be used as smart carriers for multiple cargos, including both naked and nanoparticle-encapsulated chemotherapeutics, genes, and radioisotopes. Recent works have attempted to specialize hydrogels for cancer research; we comprehensively review this topic for the first time, synthesizing past results and defining paths for future work.

A new targeted delivery approach by functionalizing drug nanocrystals through polydopamine coating

Tumor target specificity via chemotherapy is widely considered to be very effective on tumor treatment. For an ideal chemotherapeutic agent like Camptothecin (CPT) (CPT is the abbreviation for Camptothecin), improved therapeutic efficacy and high selectivity are equally important. Inspired by adhesive proteins in mussels, here we developed a novel tumor targeting peptide XQ1 grafted CPT nanocrystals with polydopamine coating as a spacer. In this study, CPT nanocrystals were coated by polymerization of dopamine that was induced by plasma-activated water under an acidic environment, and then the tumor targeting peptide was grafted onto polydopamine (PDA) (PDA is the abbreviation for polydopamine) coated CPT nanocrystals through catechol chemistry. The PDA layer had negligible effects on drug crystallinity and structure but resulted in drug nanocrystals with excellent dispersion properties, improved dissolution rate and drug stability by preventing water hydrolysis. More importantly, tumor targeting peptide XQ1 facilitated a rapid cross-membrane translocation of drug nanocrystals via receptor-mediated endocytosis, leading to efficient intracellular drug delivery. Moreover, this novel drug formulation demonstrated more potent anti-cancer activity against tumor cells in comparison with free CPT and naked CPT nanocrystals and exhibited high selectivity, all of which are attributed to the tumor target specificity property and inherent pH-dependent drug release behavior.

Phenylboronic acid-incorporated elastin-like polypeptide nanoparticle drug delivery systems

Packaging hydrophobic drugs into nanoparticles can improve their aqueous solubility, tumor-specific accumulation and therapeutic effect.

Nanotechnology-based Drug Delivery for Cancer

Nanobiotechnologies have been applied to improve drug delivery and to overcome some of the problems of drug delivery in cancer. These can be classified into many categories that include use of various nanoparticles, nanoencapsulation, targeted delivery to tumors of various organs, and combination with other methods of treatment of cancer such as radiotherapy. Nanoparticles are also used for gene therapy for cancer. Some of the technologies enable combination of diagnostics with therapeutics which will be important for the personalized management of cancer. Some of the limitations of these technologies and prospects for future development are discussed.

Multiscale benchmarking of drug delivery vectors

Cross-system comparisons of drug delivery vectors are essential to ensure optimal design. An in-vitro experimental protocol is presented that separates the role of the delivery vector from that of its cargo in determining the cell response, thus allowing quantitative comparison of different systems. The technique is validated through benchmarking of the dose-response of human fibroblast cells exposed to the cationic molecule, polyethylene imine (PEI); delivered as a free molecule and as a cargo on the surface of CdSe nanoparticles and Silica microparticles. The exposure metrics are converted to a delivered dose with the transport properties of the different scale systems characterized by a delivery time, τ. The benchmarking highlights an agglomeration of the free PEI molecules into micron sized clusters and identifies the metric determining cell death as the total number of PEI molecules presented to cells, determined by the delivery vector dose and the surface density of the cargo.

CD44 targeted chemotherapy for co-eradication of breast cancer stem cells and cancer cells using polymeric nanoparticles of salinomycin and paclitaxel

This combinational therapy is mainly aimed for complete eradication of tumor by killing both cancer cells and cancer stem cells. Salinomycin (SLM) was targeted towards cancer stem cells whereas paclitaxel (PTX) was used to kill cancer cells. Drug loaded poly (lactic-co-glycolic acid) nanoparticles were prepared by emulsion solvent diffusion method using cationic stabilizer. Size of the nanoparticles (below 150nm) was determined by dynamic light scattering technique and transmission electron microscopy. In vitro release study confirmed the sustained release pattern of SLM and PTX from nanoparticles more than a month. Cytotoxicity studies on MCF-7 cells revealed the toxicity potential of nanoparticles over drug solutions. Hyaluronic acid (HA) was coated onto the surface of SLM nanoparticles for targeting CD44 receptors over expressed on cancer stem cells and they showed the highest cytotoxicity with minimum IC50 on breast cancer cells. Synergistic cytotoxic effect was also observed with combination of nanoparticles. Cell uptake studies were carried out using FITC loaded nanoparticles. These particles showed improved cellular uptake over FITC solution and HA coating further enhanced the effect by 1.5 folds. CD44 binding efficiency of nanoparticles was studied by staining MDA-MB-231 cells with anti CD44 human antibody and CD44(+) cells were enumerated using flow cytometry. CD44(+) cell count was drastically decreased when treated with HA coated SLM nanoparticles indicating their efficiency towards cancer stem cells. Combination of HA coated SLM nanoparticles and PTX nanoparticles showed the highest cytotoxicity against CD44(+) cells. Hence combinational therapy using conventional chemotherapeutic drug and cancer stem cell inhibitor could be a promising approach in overcoming cancer recurrence due to resistant cell population.

Preparation of Engineered Salmonella Typhimurium-Driven Hyaluronic-Acid-Based Microbeads with Both Chemotactic and Biological Targeting Towards Breast Cancer Cells for Enhanced Anticancer Therapy

In this study, a new type of targeted bacteriobots is prepared and investigated as a therapeutic strategy against solid tumors. Maleimide-functionalized hyaluronic acid (HA) polymer is synthesized and cross-linked with four-arm-thiolated polyethylene glycol (PEG-SH) to form HA microbeads with diameter of 8 μm through the Michael-type addition. Docetaxel (DTX)-loaded nanoparticles are encapsulated in HA-PEG microbeads and sustained in vitro drug-release pattern of the DTX from the HA-PEG microbeads is observed for up to 96 h. Dual-targeted bacteriobots are prepared using CD 44 receptor-targeted HA microbeads synthesized via microfluidics, followed by the attachment of the flagellar bacterium Salmonella typhimurium, which have been genetically engineered for tumor targeting, onto the surface of the HA microbeads by the specific interaction between streptavidin on the HA beads and biotin on the bacteria. After the attachment of bacteria, the bacteriobots show an average velocity of 0.72 μm s(-1) and high chemotactic migration velocity of 0.43 μm s(-1) towards 4T1 cells lysates. CD 44 receptor-specific cellular uptake is verified through flow cytometry analysis and confocal imaging, demonstrating enhanced intracellular uptake in CD 44 receptor positive tumor cells compared to normal cells. Therefore, the present study suggests that these bacteriobots have dual-tumor-targeting abilities displaying their potential for targeted anticancer therapy.

Comparison of three different conjugation strategies in the construction of herceptin-bearing paclitaxel-loaded nanoparticles

We developed an improved pre-conjugation strategy, in which herceptin as a ligand was pre-conjugated with DSPE-PEG2000-Mal via chemical cross-linking, followed by conjugation onto the surface of pre-prepared paclitaxel-loaded PLGA/DODMA nanoparticles through hydrophobic interaction and electrostatic attraction for paclitaxel delivery.

Preparation and characterization of paclitaxel nanosuspension using novel emulsification method by combining high speed homogenizer and high pressure homogenization

The aim of this study was to develop an alternative, more bio-available, better tolerated paclitaxel nanosuspension (PTXNS) for intravenous injection in comparison with commercially available Taxol(®) formulation. In this study, PTXNS was prepared by emulsification method through combination of high speed homogenizer and high pressure homogenization, followed by lyophilization process for intravenous administration. The main production parameters including volume ratio of organic phase in water and organic phase (Vo:Vw+o), concentration of PTX, content of PTX and emulsification time (Et), homogenization pressure (HP) and passes (Ps) for high pressure homogenization were optimized and their effects on mean particle size (MPS) and particle size distribution (PSD) of PTXNS were investigated. The characteristics of PTXNS, such as, surface morphology, physical status of paclitaxel (PTX) in PTXNS, redispersibility of PTXNS in purified water, in vitro dissolution study and bioavailability in vivo were all investigated. The PTXNS obtained under optimum conditions had an MPS of 186.8 nm and a zeta potential (ZP) of -6.87 mV. The PTX content in PTXNS was approximately 3.42%. Moreover, the residual amount of chloroform was lower than the International Conference on Harmonization limit (60 ppm) for solvents. The dissolution study indicated PTXNS had merits including effect to fast at the side of raw PTX and sustained-dissolution character compared with Taxol(®) formulation. Moreover, the bioavailability of PTXNS increased 14.38 and 3.51 times respectively compared with raw PTX and Taxol(®) formulation.

Bioresorbable polyelectrolytes for smuggling drugs into cells

There is ample evidence that biodegradable polyelectrolyte nanocapsules are multifunctional vehicles which can smuggle drugs into cells, and release them upon endogenous activation. A large number of endogenous stimuli have already been tested in vitro, and in vivo research is escalating. Thus, the interest in the design of intelligent polyelectrolyte multilayer (PEM) drug delivery systems is clear. The need of the hour is a systematic translation of PEM-based drug delivery systems from the lab to clinical studies. Reviews on multifarious stimuli that can trigger the release of drugs from such systems already exist. This review summarizes the available literature, with emphasis on the recent progress in PEM-based drug delivery systems that are receptive in the presence of endogenous stimuli, including enzymes, glucose, glutathione, pH, and temperature, and addresses different active and passive drug targeting strategies. Insights into the current knowledge on the diversified endogenous approaches and methodological challenges may bring inspiration to resolve issues that currently bottleneck the successful implementation of polyelectrolytes into the catalog of third-generation drug delivery systems.

Cancer active targeting by nanoparticles: a comprehensive review of literature

PURPOSE

Cancer is one of the leading causes of death, and thus, the scientific community has but great efforts to improve cancer management. Among the major challenges in cancer management is development of agents that can be used for early diagnosis and effective therapy. Conventional cancer management frequently lacks accurate tools for detection of early tumors and has an associated risk of serious side effects of chemotherapeutics. The need to optimize therapeutic ratio as the difference with which a treatment affects cancer cells versus healthy tissues lead to idea that it is needful to have a treatment that could act a the "magic bullet"-recognize cancer cells only. Nanoparticle platforms offer a variety of potentially efficient solutions for development of targeted agents that can be exploited for cancer diagnosis and treatment. There are two ways by which targeting of nanoparticles can be achieved, namely passive and active targeting. Passive targeting allows for the efficient localization of nanoparticles within the tumor microenvironment. Active targeting facilitates the active uptake of nanoparticles by the tumor cells themselves.

METHODS

Relevant English electronic databases and scientifically published original articles and reviews were systematically searched for the purpose of this review.

RESULTS

In this report, we present a comprehensive review of literatures focusing on the active targeting of nanoparticles to cancer cells, including antibody and antibody fragment-based targeting, antigen-based targeting, aptamer-based targeting, as well as ligand-based targeting.

CONCLUSION

To date, the optimum targeting strategy has not yet been announced, each has its own advantages and disadvantages even though a number of them have found their way for clinical application. Perhaps, a combination of strategies can be employed to improve the precision of drug delivery, paving the way for a more effective personalized therapy.

Surface modification of MPEG-b-PCL-based nanoparticles via oxidative self-polymerization of dopamine for malignant melanoma therapy

To enhance the therapeutic effects of chemotherapy on malignant melanoma, paclitaxel (PTX)-loaded methoxy poly(ethylene glycol)-b-poly(ε-caprolactone) nanoparticles (MPEG-b-PCL NPs) that had their surfaces modified with polydopamine (PTX-loaded MPEG-b-PCL NPs@PDA) were prepared as drug vehicles. The block copolymer MPEG-b-PCL was synthesized by ring-opening polymerization and characterized by proton nuclear magnetic resonance spectroscopy and gel permeation chromatography. The PTX-loaded NPs were prepared by a modified nanoprecipitation technique. The PTX-loaded NPs and PTX-loaded NPs@PDA were characterized in terms of size and size distribution, zeta potential, surface morphology, drug encapsulation efficiency, and drug release. Confocal laser scanning microscopy showed that coumarin-6-loaded NPs@PDA could be internalized by human melanoma cell line A875 cells. The cellular uptake efficiency of NPs was greatly enhanced after PDA modification. The antitumor efficacy of the PTX-loaded NPs@PDA was investigated in vitro by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and in vivo by a xenograft tumor model. The PTX-loaded NPs@PDA could significantly inhibit tumor growth compared to Taxol(®) and precursor PTX-loaded NPs. All the results suggested that the PTX-loaded MPEG-b-PCL NPs that had their surfaces modified with PDA are promising nanocarriers for malignant melanoma therapy.

Hybrid protein-synthetic polymer nanoparticles for drug delivery

Among the most common nanoparticulate systems, the polymeric nanocarriers have a number of key benefits, which give a great choice of delivery platforms. Nevertheless, polymeric nanoparticles possess some limitations that include use of toxic solvents in the production process, polymer degradation, drug leakage outside the diseased tissue, and polymer cytotoxicity. The combination of polymers of biological and synthetic origin is an appealing modern strategy for the production of novel nanocarriers with unprecedented properties. Proteins' interface can play an important role in determining bioactivity and toxicity and gives perspective for future development of the polymer-based nanoparticles. The design of hybrid constructs composed of synthetic polymer and biological molecules such as proteins can be considered as a straightforward tool to integrate a broad spectrum of properties and biofunctions into a single device. This review discusses hybrid protein-synthetic polymer nanoparticles with different structures and levels in complexity and functionality, in view of their applications as drug delivery systems.

Liprosomes loading paclitaxel for brain-targeting delivery by intravenous administration: in vitro characterization and in vivo evaluation

In this study, a lipid-protein nanocomplex (liprosome) was evaluated for its potential use for brain-targeting drug delivery. Liprosome was fabricated with the desolvation-ultrasonication method and characterized in terms of particle size, size distribution, zeta potential, morphology, crystal state of the drug, and in vitro release. The in vivo distribution of paclitaxel loading lipid-protein nanocomplex (PTX-liprosome) and Taxol were compared after i.v. administration in mice. The prepared PTX-liprosome has a high entrapment efficiency (>90%), small particle size (approximately 110 nm), and narrow distribution (P.I.<0.2). Transmission electron microscopy (TEM) indicated that liprosome had a spherical multilayer structure. X-ray photoelectron spectroscopy (XPS) showed that the conjugate of PTX and BSA was in the interior of the PTX-liprosome. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) demonstrated that the drug existed in a molecular or amorphous state. Fourier transform infrared spectroscopy (FTIR) suggested that the hydrophobic interactions, electrostatic interactions and hydrogen bonds among of the PTX, lipid and protein play an important role during the formation of the PTX-liprosome. The hemolysis test showed a good safety profile for the intravenous administration of liprosome. The result of the in vivo distribution suggested that liprosome increased the drug uptake by the brain tissue and decreased drug accumulation in non-target organs. Therefore, liprosome is a potential drug delivery system for transporting PTX to the brain.

Surface-coated PLA nanoparticles loaded with temozolomide for improved brain deposition and potential treatment of gliomas: development, characterization and in vivo studies

Hydrophobicity of PLA nanoparticles makes them a good substrate for macrophageal and reticulo-endothelial system uptake. Long-circulating properties can be imparted to these particles by coating them with hydrophilic stabilizers. Surface-modified PLA nanoparticles loaded with anti-cancer agent temozolomide were fabricated by solvent evaporation method and coated with surface modifiers. Selection of the surface modifier was based upon uptake of nanoparticles by K9 cells (liver cells). The particles were prepared and characterized for various physicochemical properties using transmission electron microscopy, differential scanning calorimetry, powder X-ray diffraction and in vitro dissolution studies. In vitro BBB permeation studies were performed using the co-culture model developed by using Madin-Darby canine kidney and C6 glioma cells as endothelial and glial cells, respectively. In vitro C6 glioma cell cytotoxicity, cellular proliferation, cellular migration and cellular uptake studies due to developed nanoparticles was assessed. In vivo studies such as pharmacokinetics, qualitative and quantitative biodistribution studies were performed for the developed nanoparticles. Drug-loaded nanoparticles with entrapment efficiency of 50% were developed. PEG-1000 and polysorbate-80 coated nanoparticles were least taken up by the liver cells. Characterization of the nanoparticles revealed formation of spherical shape nanoparticles, with no drug and excipient interaction. In vivo pharmacokinetics of developed nanoparticles depicted enhancement of half-life, area under the curve and mean residence time of the drug. Qualitative and quantitative biodistribution studies confirmed enhanced permeation of the drug into the brain upon loading into nanoparticles with less deposition in the highly perfused organs like lung, liver, spleen, heart and kidney.

In vitro and in vivo anticancer activity of surface modified paclitaxel attached hydroxyapatite and titanium dioxide nanoparticles

Targeted drug delivery using nanocrystalline materials delivers the drug at the diseased site. This increases the efficacy of the drug in killing the cancer cells. Surface modifications were done to target the drug to a particular receptor on the cell surface. This paper reports synthesis of hydroxyapatite and titanium dioxide nanoparticles and modification of their surface with polyethylene glycol (PEG) followed by folic acid (FA). Paclitaxel, an anticancer drug, is attached to functionalized hydroxyapatite and titanium dioxide nanoparticles. The pure and functionalised nanoparticles are characterised with XRD, TEM and UV spectroscopy. Anticancer analysis was carried out in DEN induced hepatocarcinoma animals. Biochemical, hematological and histopathological analysis show that the surface modified paclitaxel attached nanoparticles have an higher anticancer activity than the pure paclitaxel and surface modified nanoparticles without paclitaxel. This is due to the targeting of the drug to the folate receptor in the cancer cells.

Tumor cell membrane-targeting pH-dependent electron donor-acceptor fluorescence systems with low background signals

Minimizing the background signal is crucial for developing tumor-imaging techniques with sufficient specificity and sensitivity. Here we use pH difference between healthy tissues and tumor and tumor targeting delivery to achieve this goal. We synthesize fluorophore-dopamine conjugate as pH-dependent electron donor-acceptor fluorescence system. Fluorophores are highly sensitive to electron-transfer processes, which can alter their optical properties. The intrinsic redox properties of dopamine are oxidation of hydroquinone to quinone at basic pH and reduction of quinone to hydroquinone at acidic pH. Quinone can accept electron then quench fluorescence. We design tumor cell membrane-targeting carrier for delivery. We demonstrate quenched fluorophore-quinone can be specially transferred to tumor extracellular environment and tumor-accumulated fluorophore can be activated by acidic pH. These tumor-targeting pH-dependent electron donor-acceptor fluorescence systems may offer new opportunity for developing tumor-imaging techniques.

Mind the gap: a survey of how cancer drug carriers are susceptible to the gap between research and practice

With countless research papers using preclinical models and showing the superiority of nanoparticle design over current drug therapies used to treat cancers, it is surprising how deficient the translation of these nano-sized drug carriers into the clinical setting is. This review article seeks to compare the preclinical and clinical results for Doxil®, PK1, Abraxane®, Genexol-PM®, Xyotax™, NC-6004, Mylotarg®, PK2, and CALAA-01. While not comprehensive, it covers nano-sized drug carriers designed to improve the efficacy of common drugs used in chemotherapy. While not always available or comparable, effort was made to compare the pharmacokinetics, toxicity, and efficacy between the animal and human studies. Discussion is provided to suggest what might be causing the gap. Finally, suggestions and encouragement are dispensed for the potential that nano-sized drug carriers hold.