Evaluation of pegylated lipid nanocapsules versus complement system activation and macrophage uptake

Serial multiple crossed immunoelectrophoresis at a microscale: A stamp-sized 2D immunoanalysis of protein C3 activation caused by nanoparticles

Crossed immunoelectrophoresis (C-IE) is used to detect and quantify specific proteins. An application allowed the evaluation of complement system activation by nanomaterials. The work aimed to improve the C-IE toward a higher throughput and less tedious method. A new concept was implemented to prepare and run agarose gels. The first and the second dimension of electrophoresis were performed on a single gel plate, prepared before the beginning of the analysis. Several samples were migrated simultaneously on the same migration line. Up to 35 analyses were run at once, providing stamp-sized electrophoregrams (2.8 × 3 cm(2) ) maintaining the performance of the original method performed on 5 × 7 cm(2) gel slabs. Robustness and precision of the method were demonstrated through a validation approach using ANOVA. Handling, experimental duration, amount of reagents, and overall cost of one analysis were considerably reduced compared to the original method. With the same equipment, seven times more analyses can be performed in one run. C-IE can be used to analyze many types of proteins. The new experimental modalities were suitable for the application developed in the present work that was to evaluate activation of protein C3 of the complement system triggered by nanomaterials.

PEGylation as a strategy for improving nanoparticle-based drug and gene delivery

Coating the surface of nanoparticles with polyethylene glycol (PEG), or "PEGylation", is a commonly used approach for improving the efficiency of drug and gene delivery to target cells and tissues. Building from the success of PEGylating proteins to improve systemic circulation time and decrease immunogenicity, the impact of PEG coatings on the fate of systemically administered nanoparticle formulations has, and continues to be, widely studied. PEG coatings on nanoparticles shield the surface from aggregation, opsonization, and phagocytosis, prolonging systemic circulation time. Here, we briefly describe the history of the development of PEGylated nanoparticle formulations for systemic administration, including how factors such as PEG molecular weight, PEG surface density, nanoparticle core properties, and repeated administration impact circulation time. A less frequently discussed topic, we then describe how PEG coatings on nanoparticles have also been utilized for overcoming various biological barriers to efficient drug and gene delivery associated with other modes of administration, ranging from gastrointestinal to ocular. Finally, we describe both methods for PEGylating nanoparticles and methods for characterizing PEG surface density, a key factor in the effectiveness of the PEG surface coating for improving drug and gene delivery.

The melding of nanomedicine in thrombosis imaging and treatment: a review

Thromboembolic diseases constitute a plague in our century, wherein an imbalance of hemostasis leads to thrombus formation and vessels constriction reducing blood flow. Hence, the recent rise of nanomedicine gives birth to advanced diagnostic modalities and therapeutic agents for the early diagnosis and treatment of such diseases. Multimodal nanoagents for the detection of intravascular thrombi and nanovehicles for thrombus-targeted fibrinolytic therapy are few paradigms of nanomedicine approaches to overcome current diagnostic treatment roadblocks and persistent clinical needs. This review highlights the nanomedicine strategies to improve the imaging and therapy of acute thrombi by nanoparticles and nanotheranostics, the detailed imaging of thrombogenic proteins and platelets via atomic force microscopy with the knowledge basis of thrombosis pathophysiology and nanotoxicity.

Lay abstract: The present review highlights the perspectives of nanomedicine in enhancing the diagnostic and therapeutic strategies to deal with thrombosis. The basics in thrombosis are highlighted to provide the reader with better comprehension of the application of nanotools and various multimodal nanocarriers for diagnosis, targeted therapy and monitoring of the disease. The visualization and treatment of acute thrombi using multifunctional nanoparticles and nanotheranostics, along with the structural investigation of the blood-clotting proteins exploiting the atomic force microscopy capabilities are comprehensively described. At the same time, toxicity and biocompatibility issues regarding nanoparticles are discussed.

Ivermectin-loaded lipid nanocapsules: toward the development of a new antiparasitic delivery system for veterinary applications

Ivermectin (IVM) is probably one of the most widely used antiparasitic drugs worldwide, and its efficacy is well established. However, slight differences in formulation may change the plasma kinetics, the biodistribution, and in consequence, the efficacy of this compound. The present study focuses on the development of a novel nanocarrier for the delivery of lipophilic drugs such as IVM and its potential application in antiparasitic control. Lipid nanocapsules (LNC) were prepared by a new phase inversion procedure and characterized in terms of size, surface potential, encapsulation efficiency, and physical stability. A complement activation assay (CH50) and uptake experiments by THP-1 macrophage cells were used to assess the stealth properties of this nanocarrier in vitro. Finally, a pharmacokinetics and biodistribution study was carried out as a proof of concept after subcutaneous (SC) injection in a rat model. The final IVM-LNC suspension displayed a narrow size distribution and an encapsulation rate higher than 90 % constant over the evaluated time (60 days). Through flow cytometry and blood permanence measurements, it was possible to confirm the ability of these particles to avoid the macrophage uptake. Moreover, the systemic disposition of IVM in the LNC administered by the SC route was higher (p < 0.05) (1367 ng h/ml) compared to treatment with a commercial formulation (CF) (1193 ng.h/ml), but no significant differences in the biodistribution pattern were found. In conclusion, this new carrier seems to be a promising therapeutic approach in antiparasitic control and to delay the appearance of resistance.

Immune cell impact of three differently coated lipid nanocapsules: pluronic, chitosan and polyethylene glycol

Lipid nanocapsules (NCs) represent promising tools in clinical practice for diagnosis and therapy applications. However, the NC appropriate functionalization is essential to guarantee high biocompatibility and molecule loading ability. In any medical application, the immune system-impact of differently functionalized NCs still remains to be fully understood. A comprehensive study on the action exerted on human peripheral blood mononuclear cells (PBMCs) and major immune subpopulations by three different NC coatings: pluronic, chitosan and polyethylene glycol-polylactic acid (PEG) is reported. After a deep particle characterization, the uptake was assessed by flow-cytometry and confocal microscopy, focusing then on apoptosis, necrosis and proliferation impact in T cells and monocytes. Cell functionality by cell diameter variations, different activation marker analysis and cytokine assays were performed. We demonstrated that the NCs impact on the immune cell response is strongly correlated to their coating. Pluronic-NCs were able to induce immunomodulation of innate immunity inducing monocyte activations. Immunomodulation was observed in monocytes and T lymphocytes treated with Chitosan-NCs. Conversely, PEG-NCs were completely inert. These findings are of particular value towards a pre-selection of specific NC coatings depending on biomedical purposes for pre-clinical investigations; i.e. the immune-specific action of particular NC coating can be excellent for immunotherapy applications.

In Situ formation of pH-/thermo-sensitive nanohybrids via friendly-assembly of poly(N-vinylpyrrolidone) onto LAPONITE®

Decoration of silicate nanodisks with a pH-sensitive polymer allows for the effective delivery of an anticancer drug in cancer cells with high efficacy.

Uptake of silver nanoparticles by monocytic THP-1 cells depends on particle size and presence of serum proteins

Human health risks by silver nanoparticle (AgNP) exposure are likely to increase due to the increasing number of NP-containing products and demonstrated adverse effects in various cell lines. Unfortunately, results from (toxicity) studies are often based on exposure dose and are often measured only at a fixed time point. NP uptake kinetics and the time-dependent internal cellular concentration are often not considered. Macrophages are the first line of defense against invading foreign agents including NPs. How macrophages deal with the particles is essential for potential toxicity of the NPs. However, there is a considerable lack of uptake studies of particles in the nanometer range and macrophage-like cells. Therefore, uptake rates were determined over 24 h for three different AgNPs sizes (20, 50 and 75 nm) in medium with and without fetal calf serum. Non-toxic concentrations of 10 ng Ag/mL for monocytic THP-1 cells, representing realistic exposure concentration for short-term exposures, were chosen. The uptake of Ag was higher in medium without fetal calf serum and showed increasing uptake for decreasing NP sizes, both on NP mass and on number basis. Internal cellular concentrations reached roughly 32/10 %, 25/18 % and 21/15 % of the nominal concentration in the absence of fetal calf serum/with fetal calf serum for 20-, 50- and 75-nm NPs, respectively. Our research shows that uptake kinetics in macrophages differ for various NP sizes. To increase the understanding of the mechanism of NP toxicity in cells, the process of uptake (timing) should be considered.

Cellular processing and destinies of artificial DNA nanostructures

This review gives a panoramic view of the many DNA nanotechnology applications in cells, mechanistic understanding of how and where their interactions occur and their subsequent outcomes.

Gold nanostars co-coated with the Cu(II) complex of a tetraazamacrocyclic ligand

The twelve-membered tetraazamacrocyclic ligand L1 bears an appended lipoic acid unit, whose disulphide ring is an efficient grafting moiety for the surface of gold nanostars (GNS). The GNS that were used featured a localized surface plasmon resonance (LSPR) absorption at ∼800 nm, i.e. in the near infrared (NIR). We investigated different approaches for coating them with the Cu(2+) complex of L1. While the direct reaction of [CuL1](2+) with as-prepared GNS led to aggregation, an initial coating step with polyethyleneglycol-thiol (PEG-SH) was found to be advantageous. Displacement reactions were carried out on pegylated GNS either with [CuL1](2+), directly generating [Cun(L1@GNS)](2n+), or with void L1, thus obtaining @GNS that coordinates Cu(2+) in a second step. In both cases, even with a large excess of the competing disulphide moiety, only partial displacement of PEG-SH is observed, obtaining ca. 500-1500 [CuL1](2+) per GNS depending on the conditions, with PEG-SH remaining in the [Cun(L1@GNS)](2n+) hybrids and imparting them with remarkable stability. Comparison of the photothermal and two-photon luminescence (TPL) properties of the GNS between the pegylated GNS and [Cun(L1@GNS)](2n+) revealed that the grafted copper complex does not change them to any extent. Finally, the stability against demetallation and transmetallation of the complexes, as well as the fast kinetics of complexation of the monodispersed macrocycle and of L1@GNS, have been examined, suggesting [Cun(L1@GNS)](2n+) as a device capable of TPL optical tracking and NIR photothermal therapy and as a possible agent for PET imaging.

Biodistribution and Toxicity of X-Ray Iodinated Contrast Agent in Nano-emulsions in Function of Their Size

PURPOSE

This study aimed to investigate the impact of the size of X-ray iodinated contrast agent in nano-emulsions, on their toxicity and fate in vivo.

METHODS

A new compound, triiodobenzoate cholecalciferol, was synthetized, formulated as nano-emulsions, and followed after i.v. administration in mice by X-ray imaging (micro computed tomography). Physicochemical characterization and process optimization allowed identifying a good compromise between X-ray contrasting properties, monodispersity and stability. This also allowed selecting two formulations with different sizes, hydrodynamic diameters of 55 and 100 nm, but exactly the same composition. In vitro experiments were performed on two cell lines, namely hepatocytes (BNL-CL2) and macrophages (RAW264.7).

RESULTS

Cell viability studies, cell uptake observations by confocal microscopy, and uptake quantification by fluorimetry, disclosed clear differences between two formulations, as well as between two types of cell lines. After i.v. injection of the two iodinated nano-emulsions in mice, CT scans provided the quantification of the pharmacokinetics and biodistributions. We finally showed that the size in the nano-emulsions has not a real impact on the pharmacokinetics and biodistributions, but has a strong influence on their toxicity, corroborating the in vitro results.

CONCLUSIONS

This study shows that the size of the nanocarrier significantly matters, likely due to highly different interactions with cells and tissues. Graphical Abstract A study on the effect of the size of cholecciferol nano-emulsions, on their in vivo becoming, through X-ray imaging modality.

Nanoparticle mediated drug delivery of rolipram to tyrosine kinase B positive cells in the inner ear with targeting peptides and agonistic antibodies

Aim: Systemic pharmacotherapies have limitation due to blood-labyrinth barrier, so local delivery via the round window membrane opens a path for effective treatment. Multifunctional nanoparticle (NP)-mediated cell specific drug delivery may enhance efficacy and reduce side effects. Different NPs with ligands to target TrkB receptor were tested. Distribution, uptake mechanisms, trafficking, and bioefficacy of drug release of rolipram loaded NPs were evaluated.

Methods: We tested lipid based nanocapsules (LNCs), Quantum Dot, silica NPs with surface modification by peptides mimicking TrkB or TrkB activating antibodies. Bioefficacy of drug release was tested with rolipram loaded LNCs to prevent cisplatin-induced apoptosis. We established different cell culture models with SH-SY-5Y and inner ear derived cell lines and used neonatal and adult mouse explants. Uptake and trafficking was evaluated with FACS and confocal as well as transmission electron microscopy.

Results: Plain NPs show some selectivity in uptake related to the in vitro system properties, carrier material, and NP size. Some peptide ligands provide enhanced targeted uptake to neuronal cells but failed to show this in cell cultures. Agonistic antibodies linked to silica NPs showed TrkB activation and enhanced binding to inner ear derived cells. Rolipram loaded LNCs proved as effective carriers to prevent cisplatin-induced apoptosis.

Discussion: Most NPs with targeting ligands showed limited effects to enhance uptake. NP aggregation and unspecific binding may change uptake mechanisms and impair endocytosis by an overload of NPs. This may affect survival signaling. NPs with antibodies activate survival signaling and show effective binding to TrkB positive cells but needs further optimization for specific internalization. Bioefficiacy of rolipram release confirms LNCs as encouraging vectors for drug delivery of lipophilic agents to the inner ear with ideal release characteristics independent of endocytosis.

Design attributes of long-circulating polymeric drug delivery vehicles

Following systemic administration polymeric drug delivery vehicles allow for a controlled and targeted release of the encapsulated medication at the desired site of action. For an elevated and organ specific accumulation of their cargo, nanocarriers need to avoid opsonization, activation of the complement system and uptake by macrophages of the mononuclear phagocyte system. In this respect, camouflaged vehicles revealed a delayed elimination from systemic circulation and an improved target organ deposition. For instance, a steric shielding of the carrier surface by poly(ethylene glycol) substantially decreased interactions with the biological environment. However, recent studies disclosed possible deficits of this approach, where most notably, poly(ethylene glycol)-modified drug delivery vehicles caused significant immune responses. At present, identification of novel potential carrier coating strategies facilitating negligible immune reactions is an emerging field of interest in drug delivery research. Moreover, physical carrier properties including geometry and elasticity seem to be very promising design attributes to surpass numerous biological barriers, in order to improve the efficacy of the delivered medication.

In vivo evaluation of paclitaxel-loaded lipid nanocapsules after intravenous and oral administration on resistant tumor

Aim & methods: The aim of the present work was to encapsulate paclitaxel (Ptx) in various lipid nanocapsules (LNCs) formulations and then to compare their pharmacokinetics and efficacy on a subcutaneous isograft model in rats. Results: Three different Ptx formulations were obtained. Drug payloads ranged from 1.32 to 3.62 mg Ptx/g of formulation. After oral administration the area under concentration–time curve was higher (p < 0.05) if Ptx was encapsulated, (1,2 Distearoyl-sn-glycero-3–phosphoethanolamine-N-[amino(PEG)] (DSPE-PEG-NH2)) LNCs displaying the highest area under concentration–time curve (p < 0.05). Efficacy was better than control for standard LNCs after oral administration (p < 0.05) and for (DSPE-PEG-NH2) LNCs after intravenous administration. Despite good absorption, (DSPE-PEG-NH2) LNCs failed to remain efficient after oral route. Conclusion: This study highlights the importance of efficacy studies paired to pharmacokinetic studies for nanomedicines.

Amphiphilic polymer-mediated formation of laponite-based nanohybrids with robust stability and pH sensitivity for anticancer drug delivery

The development of pH-sensitive drug delivery nanosystems that present a low drug release at the physiological pH and are able to increase the extent of the release at a lower pH value (like those existent in the interstitial space of solid tumors (pH 6.5) and in the intracellular endolysosomal compartments (pH 5.0)) is very important for an efficient and safe cancer therapy. Laponite (LP) is a synthetic silicate nanoparticle with a nanodisk structure (25 nm in diameter and 0.92 nm in thickness) and negative-charged surface, which can be used for the encapsulation of doxorubicin (DOX, a cationic drug) through electrostatic interactions and exhibit good pH sensitivity in drug delivery. However, the colloidal instability of LP still limits its potential clinical applications. In this study, we demonstrate an elegant strategy to develop stable Laponite-based nanohybrids through the functionalization of its surface with an amphiphile PEG-PLA copolymer by a self-assembly process. The hydrophobic block of PEG-PLA acts as an anchor that binds to the surface of drug-loaded LP nanodisks, maintaining the core structure, whereas the hydrophilic PEG part serves as a protective stealth shell that improves the whole stability of the nanohybrids under physiological conditions. The resulting nanocarriers can effectively load the DOX drug (the encapsulation efficiency is 85%), and display a pH-enhanced drug release behavior in a sustained way. In vitro biological evaluation indicated that the DOX-loaded nanocarriers can be effectively internalized by CAL-72 cells (an osteosarcoma cell line), and exhibit a remarkable higher anticancer cytotoxicity than free DOX. The merits of Laponite/PEG-PLA nanohybrids, such as good cytocompatibility, excellent physiological stability, sustained pH-responsive release properties, and improved anticancer activity, make them a promising platform for the delivery of other therapeutic agents beyond DOX.

Barriers to drug delivery in solid tumors

Over the last decade, significant progress has been made in the field of drug delivery. The advent of engineered nanoparticles has allowed us to circumvent the initial limitations to drug delivery such as pharmacokinetics and solubility. However, in spite of significant advances to tumor targeting, an effective treatment strategy for malignant tumors still remains elusive. Tumors possess distinct physiological features which allow them to resist traditional treatment approaches. This combined with the complexity of the biological system presents significant hurdles to the site-specific delivery of therapeutic drugs. One of the key features of engineered nanoparticles is that these can be tailored to execute specific functions. With this review, we hope to provide the reader with a clear understanding and knowledge of biological barriers and the methods to exploit these characteristics to design multifunctional nanocarriers, effect useful dosing regimens and subsequently improve therapeutic outcomes in the clinic.

Inhalable PEGylated Phospholipid Nanocarriers and PEGylated Therapeutics for Respiratory Delivery as Aerosolized Colloidal Dispersions and Dry Powder Inhalers

Nanomedicine is making groundbreaking achievements in drug delivery. The versatility of nanoparticles has given rise to its use in respiratory delivery that includes inhalation aerosol delivery by the nasal route and the pulmonary route. Due to the unique features of the respiratory route, research in exploring the respiratory route for delivery of poorly absorbed and systemically unstable drugs has been increasing. The respiratory route has been successfully used for the delivery of macromolecules like proteins, peptides, and vaccines, and continues to be examined for use with small molecules, DNA, siRNA, and gene therapy. Phospholipid nanocarriers are an attractive drug delivery system for inhalation aerosol delivery in particular. Protecting these phospholipid nanocarriers from pulmonary immune system attack by surface modification by polyethylene glycol (PEG)ylation, enhancing mucopenetration by PEGylation, and sustaining drug release for controlled drug delivery are some of the advantages of PEGylated liposomal and proliposomal inhalation aerosol delivery. This review discusses the advantages of using PEGylated phospholipid nanocarriers and PEGylated therapeutics for respiratory delivery through the nasal and pulmonary routes as inhalation aerosols.

Biodegradable nanoparticles for intracellular delivery of antimicrobial agents

Biodegradable nanoparticles have emerged as a promising strategy for ferrying antimicrobial agents into specific cells due to their unique properties. This review discusses the current progress and challenges of biodegradable nanoparticles for intracellular antimicrobial delivery to understand design principles for the development of ideal nanocarriers. The intracellular delivery performances of biodegradable nanoparticles for diverse antimicrobial agents are first summarized. Second, the cellular internalization and intracellular trafficking, degradation and release kinetics of nanoparticles as well as their relation with intracellular delivery of encapsulated antimicrobial agents are provided. Third, the influences of nanoparticle properties on the cellular internalization and intracellular fate of nanoparticles and their payload antimicrobial agents are discussed. Finally, the challenges and perspectives of nanoparticles for intracellular delivery of antimicrobial agents are addressed. The review will be helpful to the scientists who are interested in searching for more efficient nanosystem strategies for intracellular delivery of antimicrobial agents.

Endocytosis and exocytosis of nanoparticles in mammalian cells

Engineered nanoparticles that can be injected into the human body hold tremendous potential to detect and treat complex diseases. Understanding of the endocytosis and exocytosis mechanisms of nanoparticles is essential for safe and efficient therapeutic application. In particular, exocytosis is of significance in the removal of nanoparticles with drugs and contrast agents from the body, while endocytosis is of great importance for the targeting of nanoparticles in disease sites. Here, we review the recent research on the endocytosis and exocytosis of functionalized nanoparticles based on various sizes, shapes, and surface chemistries. We believe that this review contributes to the design of safe nanoparticles that can efficiently enter and leave human cells and tissues.

Mechanism of macromolecular structure evolution in self-assembled lipid nanoparticles for siRNA delivery

Lipid nanoparticles (LNPs) are a leading platform for therapeutic delivery of small interfering RNAs (siRNAs). Optimization of LNPs as therapeutic products is enabled by the development of structure-activity relationships (SAR) linking LNP physiochemical and macromolecular properties to bioperformance. Methods by which LNP properties can be rationally manipulated are thus critical enablers of this fundamental knowledge build. In this work, we present a mechanistic study of LNP self-assembly via a rapid antisolvent precipitation process and identify critical physiochemical and kinetic parameters governing the evolution of LNP three-dimensional macromolecular structure as a biorelevant SAR feature. Using small-angle X-ray scattering, LNPs are shown to undergo a temporal evolution in macromolecular structure during self-assembly, rearranging from initially disordered phases after precipitation into well-ordered structures following a necessary annealing stage of the assembly sequence. The ability of LNPs to undergo structural reorganization is shown to be effected by the chemical nature of the aqueous antisolvent used for precipitation. Antisolvents of varying buffering species differentially influence LNP macromolecular features, revealing a new participatory role of buffer ions in LNP self-assembly. Furthermore, the formation of macromolecular structure in LNPs is shown to improve the efficiency of siRNA encapsulation, thereby offering a simple, nonchemical route for preparation of high-payload LNPs that minimize the dose of lipid excipients. The developed LNP precipitation process and mechanistic understanding of self-assembly are shown to be generalizable, enabling the production of LNPs with a tunable range of macromolecular features, as evidenced by the cubic, hexagonal, and oligo-lamellar phase LNPs exemplarily generated.

Immuno- and hemocompatibility of amino acid pairing peptides for potential use in anticancer drug delivery

Amino acid pairing peptide-based nanoparticles were recently introduced as promising carriers for hydrophobic anticancer drugs. The AC8 peptide, n-FEFQFNFK-c, is based on the amino acid pairing (AAP) design with 8 amino acids and hence the designated name AAP8. The nanoparticles (NPs) AAP8 have modified either on the C-terminal or on both terminal, by conjugation with diethylene glycol (DEG) . Here, the in vitro biocompatibilities of the NPs and their modified versions were compared and the potential of these NPs as carriers for the hydrophobic anticancer drug pirarubicin was determined as well as the peptide-drug co-assembly complexes. The toxicity of the NPs, DEGylated NPs, and blended mixtures with pirarubicin, was tested against the human adenocarcinoma lung cancer cell line, A549. The amino-end DEGylated NP, (NP-I), had superior biocompatibility over the non-modified NPs or double DEGylated NPs (NP-II). NP-I had very low hemolytic activity (1%) while NP and NP-II had marginal (8%) and acceptable (5%) hemolytic activity, respectively. All three types of NPs did not activate the complement system via the classical and alternative pathways nor did they activate the anaphylotoxin C3a. However, NP-II and its drug complex effectively activate the complement terminal attack complex. The lectin pathway was not activated by NP-I and NP-II, but was to a small extent by the non-modified NPs, with no lectin activation when complexed with drug. These results indicate NP-I is the most promising peptide for use as a drug delivery system, highlighting the importance of proper modification in peptides for drug delivery systems.

Durable expression of minicircle DNA-liposome-delivered androgen receptor cDNA in mice with hepatocellular carcinoma

Background. The most common gene-based cancer therapies involve the suppression of oncogenic molecules and enhancement of the expression of tumor-suppressor genes. Studies in noncancer disease animal models have shown that minicircle (MC) DNA vectors are easy to deliver and that the proteins from said MC-carrying DNA vectors are expressed over a long period of time. However, delivery of therapeutic genes via a liposome-mediated, MC DNA complex has never been tested in vascular-rich hepatocellular carcinoma (HCC). Liposome-mediated DNA delivery exhibits high in vivo transfection efficiency and minimal systemic immune response, thereby allowing for repetitive interventions. In this study, we evaluated the efficacy of delivering an MC-liposome vector containing a 3.2 kb androgen receptor (AR; HCC metastasis suppressor) cDNA into Hepatitis B Virus- (HBV-) induced HCC mouse livers. Results. Protein expression and promoter luciferase assays revealed that liposome-encapsulated MC-AR resulted in abundant functional expression of AR protein (100 kD) for up to two weeks. The AR cDNA was also successfully delivered into normal livers and diseased livers, where it was persistently expressed. In both normal livers and livers with tumors, the expression of AR was detectable for up to 60 days. Conclusion. Our results show that an MC/liposome delivery system might improve the efficacy of gene therapy in patients with HCC.

Carboxymethyl chitosan-poly(amidoamine) dendrimer core-shell nanoparticles for intracellular lysozyme delivery

Intracellular delivery of native, active proteins is challenging due to the fragility of most proteins. Herein, a novel polymer/protein polyion complex (PIC) nanoparticle with core-shell structure was prepared. Carboxymethyl chitosan-grafted-terminal carboxyl group-poly(amidoamine) (CM-chitosan-PAMAM) dendrimers were synthesized by amidation and saponification reactions. (1)H NMR was used to characterize CM-chitosan-PAMAM dendrimers. The TEM images and results of lysozyme loading efficiency indicated that CM-chitosan-PAMAM dendrimers could self-assemble into core-shell nanoparticles, and lysozyme was efficiently encapsulated inside the core of CM-chitosan-PAMAM dendrimer nanoparticles. Activity of lysozyme was completely inhibited by CM-chitosan-PAMAM Dendrimers at physiological pH, whereas it was released into the medium and exhibited a significant enzymatic activity in an acidic intracellular environment. Moreover, the CM-chitosan-PAMAM dendrimer nanoparticles did not exhibit significant cytotoxicity in the range of concentrations below 3.16 mg/ml. The results indicated that these CM-chitosan-PAMAM dendrimers have excellent properties as highly potent and non-toxic intracellular protein carriers, which would create opportunities for novel applications in protein delivery.

Development and in vitro evaluation of a novel lipid nanocapsule formulation of etoposide

Small cell lung cancer (SCLC) is the most aggressive carcinoma in thoracic oncology, unfortunately, despite chemotherapy, relapse is constant. The effect of etoposide, a major drug used against SCLC, can potentially be enhanced after its encapsulation in nanocarriers. The aim of this study was to use the technology of lipid nanocapsules (LNCs) to obtain nanocarriers with drug loadings compatible with clinical use and with an industrial process. Solubility studies with different co-solvent were first performed, then several process were developed to obtain LNCs. LNCs were then characterized (size, zeta potential, and drug loading). The best formulation called Ω-LNCs had a size of 54.1±2.0 nm and a zeta potential of -5.8±3.5 mV and a etoposide drug loading of 5.7±0.3mg/g. The characteristics of this formulation were maintained after freeze drying and after a 15× scale-up. Release studies in a media mimicking plasma composition showed that 40% of the drug was released from the LNCs after 48 h. Moreover the activity of etoposide after encapsulation was enhanced on H209 cells, IC50 was 100 μM and 2.5 μM for etoposide and etoposide LNCs respectively. Unfortunately the formulation failed to be more cytotoxic than etoposide alone on H69AR cells that are resistant to etoposide. This study showed that is was possible to obtain a new etoposide nanocarrier without the use of organic solvent, that the process is suitable for scale-up and freeze drying and finally that etoposide activity is maintained which is very promising for future treatment of SCLC.

Nanoemulsion loaded with lycobetaine-oleic acid ionic complex: physicochemical characteristics, in vitro, in vivo evaluation, and antitumor activity

Background

Intravenous injection of lycobetaine was found to show significant cytotoxic activity against (inter alia) Lewis lung carcinoma, but its therapeutic use is largely limited due to an extremely short half-life in blood. This study aimed at developing a novel lipid nanocarrier-based formulation for lycobetaine delivery. The formulation is feasible for scale-up production, exhibiting good parenteral acceptability and improved circulation characteristics.

Methods

To enhance its lipophilicity, oleic acid was selected to form ionic complexes with lycobetaine (LBT). The nanoemulsion loaded with LBT–oleic acid complex (LBT–OA–nanoemulsion) and PEGylated LBT–OA–nanoemulsion (NE) (LBT–OA–PEG–NE) were prepared by a simple high-pressure homogenization method.

Results

A high-encapsulation efficiency of around 97.32% ± 2.09% was obtained for LBT–OA–PEG–NE under optimized conditions. Furthermore, the in vivo pharmacokinetics and biodistribution of LBT–OA–NE, LBT–OA–PEG–NE, and free LBT were studied in rats. Free LBT and LBT–OA–PEG–NE displayed AUC_0–10h (area under the concentration-time curve from 0 to 10 hours) of 112.99 mg/L*minute and 3452.09 mg/L*minute via intravenous administration (P < 0.005), respectively. Moreover, LBT–OA–PEG–NE showed significantly lower LBT concentration in the heart, liver, and kidney, while achieving higher concentration of LBT in the lung when compared to free LBT at the same time (P < 0.005). The LBT–OA–PEG–NE exhibited higher growth inhibitory effect and longer survival time than free LBT in both heterotopic and lung metastatic tumor models.

Conclusion

These results demonstrated that LBT–OA–PEG–NE is an attractive parenteral formulation for cancer therapy.

Surface modification of lipid nanocapsules with polysaccharides: from physicochemical characteristics to in vivo aspects

Attaching polysaccharides to the surface of nanoparticles offers the possibility of modifying the physicochemical and biological properties of the core particles. The surface of lipid nanocapsules (LNCs) was modified by post-insertion of amphiphilic lipochitosan (LC) or lipodextran (LD). Modelling of these LNCs by the drop tensiometer technique revealed that the positively charged LC made the LNC surface more rigid, whereas the neutral, higher M(W) LD had no effect on the surface elasticity. Both LNC-LC and LNC-LD activated the complement system more than the blank LNC, thus suggesting increased capture by the mononuclear phagocyte system. In vitro, the positively charged LNC-LC were more efficiently bound by the model HEK293(β3) cells compared to LNC and LNC-LD. Finally, it was observed that neither LC nor LD changed the in vivo biodistribution properties of LNCs in mice. These polysaccharide-coated LNCs, especially LNC-LC, are promising templates for targeting ligands (e.g. peptides, proteins) or therapeutic molecules (e.g. siRNA).

Nanoparticle characterization: state of the art, challenges, and emerging technologies

Nanoparticles have received enormous attention as a promising tool to enhance target-specific drug delivery and diagnosis. Various in vitro and in vivo techniques are used to characterize a new system and predict its clinical efficacy. These techniques enable efficient comparison across nanoparticles and facilitate a product optimization process. On the other hand, we recognize their limitations as a prediction tool, due to inadequate applications and overly simplified test conditions. We provide a critical review of in vitro and in vivo techniques currently used for evaluation of nanoparticles and introduce emerging techniques and models that may be used complementarily.

Pharmacokinetic considerations for targeted drug delivery

Drug delivery systems involve technology designed to maximize therapeutic efficacy of drugs by controlling their biodistribution profile. In order to optimize a function of the delivery systems, their biodistribution characteristics should be systematically understood. Pharmacokinetic analysis based on the clearance concepts provides quantitative information of the biodistribution, which can be related to physicochemical properties of the delivery system. Various delivery systems including macromolecular drug conjugates, chemically or genetically modified proteins, and particulate drug carriers have been designed and developed so far. In this article, we review physiological and pharmacokinetic implications of the delivery systems.