Phase I clinical trial and pharmacokinetic evaluation of doxorubicin carried by polyisohexylcyanoacrylate nanoparticles

Antibodies against Poly(ethylene glycol) Activate Innate Immune Cells and Induce Hypersensitivity Reactions to PEGylated Nanomedicines

Nanomedicines and macromolecular drugs can induce hypersensitivity reactions (HSRs) with symptoms ranging from flushing and breathing difficulties to hypothermia, hypotension, and death in the most severe cases. Because many normal individuals have pre-existing antibodies that bind to poly(ethylene glycol) (PEG), which is often present on the surface of nanomedicines and macromolecular drugs, we examined if and how anti-PEG antibodies induce HSRs to PEGylated liposomal doxorubicin (PLD). Anti-PEG IgG but not anti-PEG IgM induced symptoms of HSRs including hypothermia, altered lung function, and hypotension after PLD administration in C57BL/6 and nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. Hypothermia was significantly reduced by blocking FcγRII/III, by depleting basophils, monocytes, neutrophils, or mast cells, and by inhibiting secretion of histamine and platelet-activating factor. Anti-PEG IgG also induced hypothermia in mice after administration of other PEGylated liposomes, nanoparticles, or proteins. Humanized anti-PEG IgG promoted binding of PEGylated nanoparticles to human immune cells and induced secretion of histamine from human basophils in the presence of PLD. Anti-PEG IgE could also induce hypersensitivity reactions in mice after administration of PLD. Our results demonstrate an important role for IgG antibodies in induction of HSRs to PEGylated nanomedicines through interaction with Fcγ receptors on innate immune cells and provide a deeper understanding of HSRs to PEGylated nanoparticles and macromolecular drugs that may facilitate development of safer nanomedicines.

Research progress in strategies to improve the efficacy and safety of doxorubicin for cancer chemotherapy

INTRODUCTION

DOX exerts strong anticancer activity and is commonly used to treat different cancers, including bone sarcomas, soft tissues, bladder, ovary, stomach, thyroid, breast, acute lymphoblastic leukemia, Hodgkin lymphoma, lung cancer, and myeloblastic leukemia. However, the cumulative doses of DOX above 550mg/m2 cause irreversible cardiotoxicity and other severe adverse effects. In this context, concerning DOX, several patents have been published in the last two decades. This activity highlights various aspects of DOX, such as registered patent analysis, pharmacological action, toxicityminimization, formulation development such as those approved by FDA, under clinical trials, and newly developed nano-delivery systems.

AREAS COVERED

This review analyzes the different aspects of DOX-based chemotherapeutics and the development of drug delivery systems in theliterature published from 2000 to early 2020.

EXPERT OPINION

DOX-based chemotherapy is still few steps away from being "perfect and safe" therapy. Certain severe systemic side effects are associated with DOX therapy. It is expected that, in the near future, DOX therapy can be much effective by selecting an ideal nanocarrier system, DOX conjugates, proper structural modifications, DOX-immunotherapy, and combination therapy. The advanced formulationsof DOX from the registered patents and recent research articles need clinical trials to bring safe treatment for cancer patients.

(Poly-cyanoacrylate) nanomedicines for cancer and beyond: Lessons learned

This « Magnum Opus » emphasizes that serendipity is a corner stone in research. The paths of discovery and innovation often result from the interdisciplinarity of scientific areas that are a priori disconnected from each other. In the 1970s, fundamental discoveries in cell biology led to unexpected advances in galenic pharmacy with the emergence of nanotechnologies for the intracellular delivery of non diffusing molecules. As well, fluorescein-loaded polyacrylamide nanocapsules were shown to deliver this fluorescent agent precisely into cellular lysosomes which represented a seminal observation. However, due to the lack of biodegradability of this carrier polymer, this approach was still far from therapeutic application. The use of cyanoacrylates as surgical glue inspired us to use this material in the design of the first biodegradable nanoparticles for human use. Capable of transporting compounds with anti-tumor activity, these polyalkylcyanoacrylate nanoparticles demonstrated the unexpected property of overcoming multi-drug resistance. This discovery led to the development of a nanomedicine that has completed phase III clinical trials for the treatment of resistant hepatocarcinoma. Going beyond the state-of-the art, a step ahead in the nanomedicine field was the drug « squalenoylation » technology, which represents a shift from the « physical » to the « chemical » encapsulation paradigm. The bioconjugation of anticancer and other drugs to squalene, a natural and biocompatible lipid, enabled a dramatic increase in drug payload, and eliminated the so-called « burst release » of drug: Two major drawbacks commonly associated with drug nanoencapsulation. The drug « squalenoylation » approach resulted in a generic nanomedicine platform with broad pharmacological applications.

A glance over doxorubicin based-nanotherapeutics: From proof-of-concept studies to solutions in the market

Cancer is one of the leading causes of death worldwide and, as such, efforts are being done to find new chemotherapeutic drugs or, alternatively, novel approaches for the delivery of old ones. In this scope, when used as vehicles for drugs, nanomaterials may potentially maximize the efficacy of the treatment and reduce its side effects, for example by a change in drug's pharmacokinetics, cell targeting and/or specific stimuli-responsiveness. This is the case of doxorubicin (DOX) that presents a broad spectrum of activity and is one of the most widely used chemotherapeutic drugs as first-line treatment. Indeed, DOX is a very interesting example of a drug for which several nanosized delivery systems have been developed over the years. While it is true that some of these systems are already in the market, it is also true that research on this subject remains very active and that there is a continuing search for new solutions. In this sense, this review takes the example of doxorubicin, not so much with the focus on the drug itself, but rather as a case study around which very diverse and imaginative nanotechnology approaches have emerged.

A journey through the emergence of nanomedicines with poly(alkylcyanoacrylate) based nanoparticles

Starting in the late 1970s, the pioneering work of Patrick Couvreur gave birth to the first biodegradable nanoparticles composed of a biodegradable synthetic polymer. These nanoparticles, made of poly(alkylcyanoacrylate) (PACA), were the first synthetic polymer-based nanoparticulate drug carriers undergoing a phase III clinical trial so far. Analyzing the journey from the birth of PACA nanoparticles to their clinical evaluation, this paper highlights their remarkable adaptability to bypass various drug delivery challenges found on the way. At present, PACA nanoparticles include a wide range of nanoparticles that can associate drugs of different chemical nature and can be administered in vivo by different routes. The most recent technologies giving the nanoparticles customised functions could also be implemented on this family of nanoparticles. Through different examples, this paper discusses the seminal role of the PACA nanoparticles' family in the development of nanomedicines.

From poly(alkyl cyanoacrylate) to squalene as core material for the design of nanomedicines

This review article covers the most important steps of the pioneering work of Patrick Couvreur and tries to shed light on his outstanding career that has been a source of inspiration for many decades. His discovery of biodegradable poly(alkyl cyanoacrylate) (PACA) nanoparticles (NPs) has opened large perspectives in nanomedicine. Indeed, NPs made from various types of alkyl cyanoacrylate monomers have been used in different applications, such as the treatment of intracellular infections or the treatment of multidrug resistant hepatocarcinoma. This latest application led to the Phase III clinical trial of Livatag^®, a PACA nanoparticulate formulation of doxorubicin. Despite the success of PACA NPs, the development of a novel type of NP with higher drug loadings and lower burst release was tackled by the discovery of squalene-based nanomedicines where the drug is covalently linked to the lipid derivative and the resulting conjugate is self-assembled into NPs. This pioneering work was accompanied by a wide range of novel applications which mainly dealt with the management of unmet medical needs (e.g. pancreatic cancer, brain ischaemia and spinal cord injury).

Use of Nanoparticles for Cerebral Cancer

Nanoparticles made of poly(butyl cyanoacrylate) (PBCA) or poly(lactic-co-glycolic acid) (PLGA) coated with polysorbate 80 or poloxamer 188 enable the transport of cytostatics such as doxorubicin across the blood-brain barrier (BBB). Following intravenous injection to rats bearing intracranially the very aggressive glioblastoma 101/8 these particles loaded with doxorubicin significantly increased the survival times and led to a complete tumor remission in 20–40% of the animals. Moreover, these particles considerably reduced the dose-limiting cardiotoxicity and also the testicular toxicity of this drug. The drug transport across the BBB by nanoparticles appears to be due to a receptor-mediated interaction with the brain capillary endothelial cells, which is facilitated by certain plasma apolipoproteins adsorbed by nanoparticles in the blood.

Biocompatible alkyl cyanoacrylates and their derivatives as bio-adhesives

Cyanoacrylate adhesives and their homologues have elicited interest over the past few decades owing to their applications in the biomedical sector, extending from tissue adhesives to scaffolds to implants to dental material and adhesives, because of their inherent biocompatibility and ability to polymerize solely with moisture, thanks to which they adhere to any substrate containing moisture such as the skin.

Antibody-functionalized polymer nanoparticle leading to memory recovery in Alzheimer's disease-like transgenic mouse model

Alzheimer's disease (AD) is a neurodegenerative disorder related, in part, to the accumulation of amyloid-β peptide (Aβ) and especially the Aβ peptide 1-42 (Aβ_1-42). The aim of this study was to design nanocarriers able to: (i) interact with the Aβ_1-42 in the blood and promote its elimination through the "sink effect" and (ii) correct the memory defect observed in AD-like transgenic mice. To do so, biodegradable, PEGylated nanoparticles were surface-functionalized with an antibody directed against Aβ_1-42. Treatment of AD-like transgenic mice with anti-Aβ_1-42-functionalized nanoparticles led to: (i) complete correction of the memory defect; (ii) significant reduction of the Aβ soluble peptide and its oligomer level in the brain and (iii) significant increase of the Aβ levels in plasma. This study represents the first example of Aβ_1-42 monoclonal antibody-decorated nanoparticle-based therapy against AD leading to complete correction of the memory defect in an experimental model of AD.

Nanomedicine safety in preclinical and clinical development: focus on idiosyncratic injection/infusion reactions

Injection/infusion reactions to nanopharmaceuticals (and particulate drug carriers) are idiosyncratic and well documented. The molecular basis of nanoparticle-mediated injection reactions is debatable, with two hypotheses as front-runners. The first is complement-activation-related 'pseudoallergy', where a causal role for nanoparticle-mediated complement activation in injection/infusion reactions is considered. However, the second hypothesis (the rapid phagocytic response hypothesis) states a transitional link from robust clearance of nanoparticles (NPs) from the blood by strategically placed responsive macrophages to adverse hemodynamic and cardiopulmonary reactions, regardless of complement activation. Here, I critically examine and discuss these hypotheses. Current experimentally derived evidence appears to be more in support of the rapid phagocytic response hypothesis than of the 'pseudoallergy' hypothesis.

Cellular uptake of nanoparticles: journey inside the cell

Nanoscale materials are increasingly found in consumer goods, electronics, and pharmaceuticals. While these particles interact with the body in myriad ways, their beneficial and/or deleterious effects ultimately arise from interactions at the cellular and subcellular level. Nanoparticles (NPs) can modulate cell fate, induce or prevent mutations, initiate cell-cell communication, and modulate cell structure in a manner dictated largely by phenomena at the nano-bio interface. Recent advances in chemical synthesis have yielded new nanoscale materials with precisely defined biochemical features, and emerging analytical techniques have shed light on nuanced and context-dependent nano-bio interactions within cells. In this review, we provide an objective and comprehensive account of our current understanding of the cellular uptake of NPs and the underlying parameters controlling the nano-cellular interactions, along with the available analytical techniques to follow and track these processes.

Bypassing adverse injection reactions to nanoparticles through shape modification and attachment to erythrocytes

Intravenously injected nanopharmaceuticals, including PEGylated nanoparticles, induce adverse cardiopulmonary reactions in sensitive human subjects, and these reactions are highly reproducible in pigs. Although the underlying mechanisms are poorly understood, roles for both the complement system and reactive macrophages have been implicated. Here, we show the dominance and importance of robust pulmonary intravascular macrophage clearance of nanoparticles in mediating adverse cardiopulmonary distress in pigs irrespective of complement activation. Specifically, we show that delaying particle recognition by macrophages within the first few minutes of injection overcomes adverse reactions in pigs using two independent approaches. First, we changed the particle geometry from a spherical shape (which triggers cardiopulmonary distress) to either rod- or disk-shape morphology. Second, we physically adhered spheres to the surface of erythrocytes. These strategies, which are distinct from commonly leveraged stealth engineering approaches such as nanoparticle surface functionalization with poly(ethylene glycol) and/or immunological modulators, prevent robust macrophage recognition, resulting in the reduction or mitigation of adverse cardiopulmonary distress associated with nanopharmaceutical administration.

Design of Insulin-Loaded Nanoparticles Enabled by Multistep Control of Nanoprecipitation and Zinc Chelation

Nanoparticle (NP) carriers provide new opportunities for controlled delivery of drugs, and have potential to address challenges such as effective oral delivery of insulin. However, due to the difficulty of efficiently loading insulin and other proteins inside polymeric NPs, their use has been mostly restricted to the encapsulation of small molecules. To better understand the processes involved in encapsulation of proteins in NPs, we study how buffer conditions, ionic chelation, and preparation methods influence insulin loading in poly(lactic-co-glycolic acid)-b-poly(ethylene glycol) (PLGA-PEG) NPs. We report that, although insulin is weakly bound and easily released from the NPs in the presence of buffer ions, insulin loading can be increased by over 10-fold with the use of chelating zinc ions and by the optimization of the pH during nanoprecipitation. We further provide ways of changing synthesis parameters to control NP size while maintaining high insulin loading. These results provide a simple method to enhance insulin loading of PLGA-PEG NPs and provide insights that may extend to other protein drug delivery systems that are subject to limited loading.

Physicochemical Characterization of the Shell Composition of PBCA-Based Polymeric Microbubbles

Microbubbles (MB) are routinely used as contrast agents for ultrasound (US) imaging. In recent years, MB have also attracted interest as drug delivery systems. Soft-shelled lipidic MB tend to be more advantageous for US imaging, while hard-shelled polymeric MB appear to be more suitable for drug delivery purposes because of their thicker shell and the resulting higher drug loading capacity. The physicochemical composition of the shell of polymeric MB, however, remains largely unknown. This study sets out to evaluate the molecular weight and polydispersity of the building blocks constituting the shell of poly(butyl cyanoacrylate) (PBCA) MB. Several different PBCA MB were synthesized, varying preparation parameters such as pH, surfactant, stirring speed, and stirring time. Using gel permeation chromatography, it is found that the number average molecular weight (M _n ) of the polymer chains in the shell of PBCA MB is 4 kDa, and that >99% of the polymer chains are below 40 kDa. This demonstrates that virtually all polymeric building blocks in the shell of PBCA MB have a size which allows for renal excretion, thereby supporting their use for drug delivery applications.

[Polymer nanoparticles for the delivery of anticancer drug]

Nanocarriers based on polymers are currently attracting much attention to perform efficient drug delivery, especially in cancer therapy. Over the last decades, different kinds of polymer nanoparticulate systems have been developed (e.g., simple, stealth, targeted, stimuli-responsive and prodrug) to propose novel, better and safer cancer therapies. This article will give a brief overview of the different classes of polymer nanoparticles that have been reported and discuss some key achievements deriving from their use in the field of cancer therapy.

Functionalized magnetic dextran-spermine nanocarriers for targeted delivery of doxorubicin to breast cancer cells

In recent decades, targeted drug delivery systems for breast cancer treatment emerged as an ideal alternative and promising solution to reduce systemic side effects of chemotherapeutic agents. In this study, the preparation and characterization of cationic doxorubicin (DOX) loaded magnetic dextran-spermine (DEX-SP) nanocarriers (DEX-SP-DOX) by ionic gelation were fully investigated. Then, anti-HER2 as a monoclonal antibody (mAb) and targeting ligand was conjugated via EDC/NHS reagents. The binding was confirmed by Bradford assay and further assessments were carried out by size and zeta potential measurements. Cytotoxicity effect and internalization of magnetic nanocarriers were assessed by MTT and Prussian blue assays and transmission electron microscopy (TEM), respectively. DLS measurements indicated that the size of nanocarriers increased from 62 to 84 nm by conjugation of anti-HER2 to them. The in vitro release of DOX from mAb conjugated magnetic nanocarriers at pHs 5 and 7.4 was found to be 85 and 55.5%, respectively. The MTT and Prussian blue assays demonstrated enhanced and selective uptake of DEX-SP-DOX-mAb by SKBR cell (HER2 overexpressed cells) in comparison with unconjugated nanocarriers due to higher cellular binding. The TEM result also confirmed cellular internalization of DEX-SP-DOX-mAb magnetic nanocarriers. These results are very promising for targeted delivery of DOX to HER2 positive breast cancer cells.

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.

Advanced targeted therapies in cancer: Drug nanocarriers, the future of chemotherapy

Cancer is the second worldwide cause of death, exceeded only by cardiovascular diseases. It is characterized by uncontrolled cell proliferation and an absence of cell death that, except for hematological cancers, generates an abnormal cell mass or tumor. This primary tumor grows thanks to new vascularization and, in time, acquires metastatic potential and spreads to other body sites, which causes metastasis and finally death. Cancer is caused by damage or mutations in the genetic material of the cells due to environmental or inherited factors. While surgery and radiotherapy are the primary treatment used for local and non-metastatic cancers, anti-cancer drugs (chemotherapy, hormone and biological therapies) are the choice currently used in metastatic cancers. Chemotherapy is based on the inhibition of the division of rapidly growing cells, which is a characteristic of the cancerous cells, but unfortunately, it also affects normal cells with fast proliferation rates, such as the hair follicles, bone marrow and gastrointestinal tract cells, generating the characteristic side effects of chemotherapy. The indiscriminate destruction of normal cells, the toxicity of conventional chemotherapeutic drugs, as well as the development of multidrug resistance, support the need to find new effective targeted treatments based on the changes in the molecular biology of the tumor cells. These novel targeted therapies, of increasing interest as evidenced by FDA-approved targeted cancer drugs in recent years, block biologic transduction pathways and/or specific cancer proteins to induce the death of cancer cells by means of apoptosis and stimulation of the immune system, or specifically deliver chemotherapeutic agents to cancer cells, minimizing the undesirable side effects. Although targeted therapies can be achieved directly by altering specific cell signaling by means of monoclonal antibodies or small molecules inhibitors, this review focuses on indirect targeted approaches that mainly deliver chemotherapeutic agents to molecular targets overexpressed on the surface of tumor cells. In particular, we offer a detailed description of different cytotoxic drug carriers, such as liposomes, carbon nanotubes, dendrimers, polymeric micelles, polymeric conjugates and polymeric nanoparticles, in passive and active targeted cancer therapy, by enhancing the permeability and retention or by the functionalization of the surface of the carriers, respectively, emphasizing those that have received FDA approval or are part of the most important clinical studies up to date. These drug carriers not only transport the chemotherapeutic agents to tumors, avoiding normal tissues and reducing toxicity in the rest of the body, but also protect cytotoxic drugs from degradation, increase the half-life, payload and solubility of cytotoxic agents and reduce renal clearance. Despite the many advantages of all the anticancer drug carriers analyzed, only a few of them have reached the FDA approval, in particular, two polymer-protein conjugates, five liposomal formulations and one polymeric nanoparticle are available in the market, in contrast to the sixteen FDA approval of monoclonal antibodies. However, there are numerous clinical trials in progress of polymer-protein and polymer-drug conjugates, liposomal formulations, including immunoliposomes, polymeric micelles and polymeric nanoparticles. Regarding carbon nanotubes or dendrimers, there are no FDA approvals or clinical trials in process up to date due to their unresolved toxicity. Moreover, we analyze in detail the more promising and advanced preclinical studies of the particular case of polymeric nanoparticles as carriers of different cytotoxic agents to active and passive tumor targeting published in the last 5 years, since they have a huge potential in cancer therapy, being one of the most widely studied nano-platforms in this field in the last years. The interest that these formulations have recently achieved is stressed by the fact that 90% of the papers based on cancer therapeutics with polymeric nanoparticles have been published in the last 6 years (PubMed search).

Nanoparticle characterization by continuous contrast variation in small-angle X-ray scattering with a solvent density gradient

Many low-density nanoparticles show a radial inner structure. This work proposes a novel approach to contrast variation with small-angle X-ray scattering based on the constitution of a solvent density gradient in a glass capillary in order to resolve this internal morphology. Scattering curves of a polymeric core–shell colloid were recorded at different suspending medium contrasts at the four-crystal monochromator beamline of PTB at the synchrotron radiation facility BESSY II. The mean size and size distribution of the particles as well as an insight into the colloid electron density composition were determined using the position of the isoscattering points in the Fourier region of the scattering curves and by examining the Guinier region in detail. These results were corroborated with a model fit to the experimental data, which provided complementary information about the inner electron density distribution of the suspended nanoparticles.

Current understanding of synergistic interplay of chitosan nanoparticles and anticancer drugs: merits and challenges

Recent advances have been made in cancer chemotherapy through the development of conjugates for anticancer drugs. Many drugs have problems of poor stability, water insolubility, low selectivity, high toxicity, and side effects. Most of the chitosan nanoparticles showed to be good drug carriers because of their biocompatibility, biodegradability, and it can be readily modified. The anticancer drug with chitosan nanoparticles displays efficient anticancer effects with a decrease in the adverse effects of the original drug due to the predominant distribution into the tumor site and a gradual release of free drug from the conjugate which enhances drug solubility, stability, and efficiency. In this review, we discuss wider applications of numerous modified chitosan nanoparticles against different tumors and also focusing on the administration of anticancer drugs through various routes. We propose the interaction between nanosized drug carrier and tumor tissue to understand the synergistic interplay. Finally, we elaborate merits of drug delivery system at the tumor site, with emphasizing future challenges in cancer chemotherapy.

Patrick Couvreur: inspiring pharmaceutical innovation

Patrick Couvreur speaks to Hannah Stanwix, Managing Comissioning Editor: Professor Patrick Couvreur received his pharmacy degree from the Université Catholique de Louvain (Louvain-la-Neuve, Belgium) in 1972. He holds a PhD in pharmaceutical technology from the same university and completed a postdoctoral fellowship at the Eidgenössische Technische Hochschule (Zürich, Switzerland). Since 1984, Professor Couvreur has been Full Professor of Pharmacy at the Paris-Sud University (Paris, France) and was holder of the Chair of Innovation Technologique at the prestigious Collège de France (Paris, France). He has published more than 450 peer-reviewed articles and has an H-index of 73, with over 19,000 citations. Professor Coureur has been recognized by numerous national and international awards, including the 2004 Pharmaceutical Sciences World Congress Award, the prestigious Host Madsen Medal, the Prix Galien, the European Pharmaceutical Scientist Award 2011 from the European Federation of Pharmaceutical Sciences, the Médaille de l’Innovation from the Centre National de la Recherche Scientifique, and recently the European Inventor Award 2013 from the European Patent Office.

Delivering nanoparticles to lungs while avoiding liver and spleen through adsorption on red blood cells

Nanoparticulate drug delivery systems are one of the most widely investigated approaches for developing novel therapies for a variety of diseases. However, rapid clearance and poor targeting limit their clinical utility. Here, we describe an approach to harness the flexibility, circulation, and vascular mobility of red blood cells (RBCs) to simultaneously overcome these limitations (cellular hitchhiking). A noncovalent attachment of nanoparticles to RBCs simultaneously increases their level in blood over a 24 h period and allows transient accumulation in the lungs, while reducing their uptake by liver and spleen. RBC-adsorbed nanoparticles exhibited ∼3-fold increase in blood persistence and ∼7-fold higher accumulation in lungs. RBC-adsorbed nanoparticles improved lung/liver and lung/spleen nanoparticle accumulation by over 15-fold and 10-fold, respectively. Accumulation in lungs is attributed to mechanical transfer of particles from the RBC surface to lung endothelium. Independent tracing of both nanoparticles and RBCs in vivo confirmed that RBCs themselves do not accumulate in lungs. Attachment of anti-ICAM-1 antibody to the exposed surface of NPs that were attached to RBCs led to further increase in lung targeting and retention over 24 h. Cellular hitchhiking onto RBCs provides a new platform for improving the blood pharmacokinetics and vascular delivery of nanoparticles while simultaneously avoiding uptake by liver and spleen, thus opening the door for new applications.

Sub-100 nm biodegradable nanoparticles: in vitro release features and toxicity testing in 2D and 3D cell cultures

A big challenge in tumor targeting by nanoparticles (NPs), taking advantage of the enhanced permeability and retention effect, is the fabrication of small size devices for enhanced tumor penetration, which is considered fundamental to improve chemotherapy efficacy. The purposes of this study are (i) to engineer the formulation of doxorubicin-loaded poly(D,L-lactic-co-glycolic acid) (PLGA)-block-poly(ethylene glycol) (PEG) NPs to obtain <100 nm devices and (ii) to translate standard 2D cytotoxicity studies to 3D collagen systems in which an initial step gradient of the NPs is present. Doxorubicin release can be prolonged for days to weeks depending on the NP formulation and the pH of the release medium. Sub-100 nm NPs are effectively internalized by HeLa cells in 2D and are less cytotoxic than free doxorubicin. In 3D, <100 nm NPs are significantly more toxic than larger ones towards HeLa cells, and the cell death rate is affected by the contributions of drug release and device transport through collagen. Thus, the reduction of NP size is a fundamental feature from both a technological and a biological point of view and must be properly engineered to optimize the tumor response to the NPs.

Nanocarriers for tracking and treating diseases

Site directed drug delivery with high efficacy is the biggest challenge in the area of current pharmaceuticals. Biodegradable polymer-based controlled release nanoparticle platforms could be beneficial for targeted delivery of therapeutics and contrast agents for a myriad of important human diseases. Biodegradable nanoparticles, which can be engineered to load multiple drugs with varied physicochemical properties, contrast agents, and cellular or intracellular component targeting moieties, have emerged as potential alternatives for tracking and treating human diseases. In this review, we will highlight the current advances in the design and execution of such platforms for their potential application in the diagnosis and treatment of variety of diseases ranging from cancer to Alzheimer's and we will provide a critical analysis of the associated challenges for their possible clinical translation.

Potential therapeutic approaches for modulating expression and accumulation of defective lamin A in laminopathies and age-related diseases

Scientific understanding of the genetic components of aging has increased in recent years, with several genes being identified as playing roles in the aging process and, potentially, longevity. In particular, genes encoding components of the nuclear lamina in eukaryotes have been increasingly well characterized, owing in part to their clinical significance in age-related diseases. This review focuses on one such gene, which encodes lamin A, a key component of the nuclear lamina. Genetic variation in this gene can give rise to lethal, early-onset diseases known as laminopathies. Here, we analyze the literature and conduct computational analyses of lamin A signaling and intracellular interactions in order to examine potential mechanisms for altering or slowing down aberrant Lamin A expression and/or for restoring the ratio of normal to aberrant lamin A. The ultimate goal of such studies is to ameliorate or combat laminopathies and related diseases of aging, and we provide a discussion of current approaches in this review.

Nanotechnology advances in upper gastrointestinal, liver and pancreatic cancer

Cancers of the upper GI tract, liver and pancreas have some of the poorest prognoses of any malignancies. Advances in diagnosis and treatment are sorely needed to improve the outcomes of patients. Nanotechnology offers the potential for constructing tailor-made therapies capable of targeting specific cancers. The particles themselves may be endowed with multifunctional properties that can be exploited for both diagnosis and treatment. Although development of therapies is still in the early stages, the use of nanoparticles (NPs) is widespread in diagnostic applications and will probably involve all areas of medicine in the future. Research into NPs is ongoing for upper gastrointestinal, liver and pancreatic cancers, and their use is becoming increasingly popular as contrast media for radiological investigations. Although more sophisticated technologies capable of active targeting are still in the early stages of assessment for clinical use, a small number of NP-based therapies are in clinical use.

Role of nanomedicine in reversing drug resistance mediated by ATP binding cassette transporters and P-glycoprotein in melanoma

Multidrug resistance (MDR) is one of the most common complex phenomenons exhibited by cancer cells. It is a very common property of melanoma postchemotherapy. MDR transporters, ATP binding cassette (ABC) transporters, play a critical role in conferring this property to melanoma cells. miRNA are post-transcriptional regulators that regulate the expression of these ABC transporters. Targeting these miRNA, in turn targeting ABC transporters with the help of nanodelivery systems to overcome drug resistance, is the primary focus for attaining successful treatment methods for drug-resistant melanoma. These delivery systems are endocytosed by the cancer cells and do not require ABC transporters for their delivery, being a promising therapeutic measure for melanoma.

Treatment of glioblastoma with poly(isohexyl cyanoacrylate) nanoparticles

Glioblastomas belong to the most devastating cancer diseases. For this reason, polysorbate 80 (Tween 80)-coated poly(isohexyl cyanoacrylate) (PIHCA) (Monorex) nanoparticles loaded with doxorubicin were developed and tested for their use for the treatment of glioblastomas. The preparation of the nanoparticles resulted in spherical particles with high doxorubicin loading. The physico-chemical properties and the release of doxorubicin from the PIHCA-nanoparticles were analysed, and the influence on cell viability of the rat glioblastoma 101/8-cell line was investigated. In vitro, the empty nanoparticles did not show any toxicity, and the anti-cancer effects of the drug-loaded nanoparticles were increased in comparison to doxorubicin solution, represented by IC(50) values. The in vivo efficacy was then tested in intracranially glioblastoma 101/8-bearing rats. Rats were treated with 3 × 1.5mg/kg doxorubicin and were sacrificed 18 days after tumour transplantation. Histological and immunohistochemical analyses were carried out to assess the efficacy of the nanoparticles. Tumour size, proliferation activity, vessel density, necrotic areas, and expression of glial fibrillary acidic protein demonstrated that doxorubicin-loaded PIHCA-nanoparticles were much more efficient than the free drug. The results suggest that poly(isohexyl cyanoacrylate) nanoparticles hold great promise for the non-invasive therapy of human glioblastomas.

Augmented anticancer efficacy of doxorubicin-loaded polymeric nanoparticles after oral administration in a breast cancer induced animal model

The present investigation reports an extensive evaluation of in vitro and in vivo anticancer efficacy of orally administered doxorubicin-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Dox-NPs) in a breast cancer induced animal model. Spherically shaped Dox-NPs were prepared with an entrapment efficiency and particle size of 55.40 ± 2.30% and 160.20 ± 0.99 nm, respectively, and freeze-dried with 5% trehalose using stepwise freeze-drying. Cytotoxicity, as investigated on C127I cell line, revealed insignificant differences between the IC(50) of free Dox and Dox-NPs treated cells in the first 24 h, while higher cytotoxicity was demonstrated by Dox-NPs, following 72 h of incubation. Confocal laser scanning microscopy (CLSM) imaging corroborated that nanoparticles were efficiently localized into the nuclear region of C127I cells. The cellular uptake profile of Dox-NPs revealed both time and concentration dependent increases in the Caco-2 cell uptake as compared to the free Dox solution. Further, Dox-NPs significantly suppressed the growth of breast tumor in female Sprague-Dawley (SD) rats upon oral administration. Finally, orally administered Dox-NPs showed a marked reduction in cardiotoxicity when compared with intravenously injected free Dox as also evident by the increased level of malondialdehyde (MDA), lactate dehydrogenase (LDH), and creatine phosphokinase (CK-MB) and reduced levels of glutathione (GSH) and superoxide dismutase (SOD). The reduced cardiotoxicity of orally administered Dox-NPs was also confirmed by the major histopathological changes in the heart tissue after the treatments of intravenously injected free Dox and orally delivered Dox-NPs.

Strategies in the design of nanoparticles for therapeutic applications

Engineered nanoparticles have the potential to revolutionize the diagnosis and treatment of many diseases; for example, by allowing the targeted delivery of a drug to particular subsets of cells. However, so far, such nanoparticles have not proved capable of surmounting all of the biological barriers required to achieve this goal. Nevertheless, advances in nanoparticle engineering, as well as advances in understanding the importance of nanoparticle characteristics such as size, shape and surface properties for biological interactions, are creating new opportunities for the development of nanoparticles for therapeutic applications. This Review focuses on recent progress important for the rational design of such nanoparticles and discusses the challenges to realizing the potential of nanoparticles.

Nanocarriers' entry into the cell: relevance to drug delivery

Nanocarriers offer unique possibilities to overcome cellular barriers in order to improve the delivery of various drugs and drug candidates, including the promising therapeutic biomacromolecules (i.e., nucleic acids, proteins). There are various mechanisms of nanocarrier cell internalization that are dramatically influenced by nanoparticles' physicochemical properties. Depending on the cellular uptake and intracellular trafficking, different pharmacological applications may be considered. This review will discuss these opportunities, starting with the phagocytosis pathway, which, being increasingly well characterized and understood, has allowed several successes in the treatment of certain cancers and infectious diseases. On the other hand, the non-phagocytic pathways encompass various complicated mechanisms, such as clathrin-mediated endocytosis, caveolae-mediated endocytosis and macropinocytosis, which are more challenging to control for pharmaceutical drug delivery applications. Nevertheless, various strategies are being actively investigated in order to tailor nanocarriers able to deliver anticancer agents, nucleic acids, proteins and peptides for therapeutic applications by these non-phagocytic routes.

Physicochemical characterization and in vitro behavior of daunorubicin-loaded poly(butylcyanoacrylate) nanoparticles

The design, preparation and characterization of poly(butylcyanoacrylate) nanoparticles as a drug-delivery system for daunorubicin is reported. A range of light scattering [photon correlation spectroscopy (PCS)], spectroscopic [(1)H nuclear magnetic resonance ((1)H NMR), Fourier transform infrared (FTIR), chromatographic [gel permeation chromatography (GPC)] and quantum chemical techniques have been employed for the physicochemical characterization of drug-loaded nanoparticles and to clarify the mechanisms of drug immobilization in the polymer matrix. The presence of daunorubicin in the polymerization medium was found to affect both the degree of polymerization and the compactness of the resulting nanoparticles. The GPC, FTIR and (1)H NMR results confirmed cytostatic immobilization in the polymer matrix, with evidence for the presence of three types of inclusion: physically entrapped, polymer-associated (due to hydrogen bonds and/or dipole-charge interactions with the polymer chains), and polymer surface-adsorbed daunorubicin. The developed colloidal delivery system has the capacity for sustained in vitro release of daunorubicin. Preliminary in vitro assays were carried out on two cell lines, DLKP and DLKP-A, which display different levels of drug resistance, to evaluate the cytotoxicity of the drug-loaded nanoparticles.

Delivery of peptide and protein drugs over the blood-brain barrier

Peptide and protein (P/P) drugs have been identified as showing great promises for the treatment of various neurodegenerative diseases. A major challenge in this regard, however, is the delivery of P/P drugs over the blood-brain barrier (BBB). Intense research over the last 25 years has enabled a better understanding of the cellular and molecular transport mechanisms at the BBB, and several strategies for enhanced P/P drug delivery over the BBB have been developed and tested in preclinical and clinical-experimental research. Among them, technology-based approaches (comprising functionalized nanocarriers and liposomes) and pharmacological strategies (such as the use of carrier systems and chimeric peptide technology) appear to be the most promising ones. This review combines a comprehensive overview on the current understanding of the transport mechanisms at the BBB with promising selected strategies published so far that can be applied to facilitate enhanced P/P drug delivery over the BBB.