Biodegradable polymeric nanoparticles based drug delivery systems

PLGA nanoparticles formed by single- or double-emulsion with vitamin E-TPGS

Poly(lactic-co-glycolic acid) (PLGA) is a biocompatible member of the aliphatic polyester family of biodegradable polymers. PLGA has long been a popular choice for drug delivery applications, particularly since it is already FDA-approved for use in humans in the form of resorbable sutures. Hydrophobic and hydrophilic drugs are encapsulated in PLGA particles via single- or double-emulsion. Briefly, the drug is dissolved with polymer or emulsified with polymer in an organic phase that is then emulsified with the aqueous phase. After the solvent has evaporated, particles are washed and collected via centrifugation for lyophilization and long term storage. PLGA degrades slowly via hydrolysis in aqueous environments, and encapsulated agents are released over a period of weeks to months. Although PLGA is a material that possesses many advantages for drug delivery, reproducible formation of nanoparticles can be challenging; considerable variability is introduced by the use of different equipment, reagents batch, and precise method of emulsification. Here, we describe in great detail the formation and characterization of microparticles and nanoparticles formed by single- or double-emulsion using the emulsifying agent vitamin E-TPGS. Particle morphology and size are determined with scanning electron microscopy (SEM). We provide representative SEM images for nanoparticles produced with varying emulsifier concentration, as well as examples of imaging artifacts and failed emulsifications. This protocol can be readily adapted to use alternative emulsifiers (e.g. poly(vinyl alcohol), PVA) or solvents (e.g. dichloromethane, DCM).

Enhanced oral bioavailability of the antiretroviral efavirenz encapsulated in poly(epsilon-caprolactone) nanoparticles by a spray-drying method

AIM

To encapsulate efavirenz (EFV) within poly(epsilon-caprolactone) (PCL) nanoparticles (NPs) and compare the oral pharmacokinetics with that of EFV-loaded micelles and pure EFV NPs.

MATERIALS & METHODS

EFV-loaded PCL NPs were produced by a double-emulsion/spray-drying method.

RESULTS

NPs displayed a hydrodynamic diameter of 200-250 nm. The encapsulation efficiency was 86-93% and the mass recovery was above 60%. X-ray diffraction indicated that drug and PCL underwent amorphization during the spray-drying process. Encapsulation within NPs significantly increased the maximum concentration in plasma and the bioavailability.

CONCLUSION

EFV-loaded PCL NPs represent a promising platform to develop scalable pharmaceuticals with improved (bio)pharmaceutic performance. Original submitted 2 May 2013; Revised submitted 4 September 2013.

Facile access to cytocompatible multicompartment micelles with adjustable Janus-cores from A-block-B-graft-C terpolymers prepared by combination of ROP and ATRP

The architecture of hydrophobic segments can determine the specific morphology of multicompartment micelles (MCMs) that are generated from aqueous assembly of amphiphilic terpolymers. In this study, we aimed to design and generate poly(ɛ-caprolactone)-based multicompartment micelles with adjustable Janus-cores. Well-defined terpolymers with a novel A-block-B-graft-C architecture composed of biologically compatible polymers, methoxy poly(ethylene glycol) (PEG), poly(ɛ-caprolactone) (PCL) and poly(2-(perfluorobutyl)ethyl methacrylate) (PPFEMA), were prepared by the stepwise use of ring-opening polymerization and atom transfer radical polymerization. Characterization of the obtained terpolymers was carried out by (1)H NMR and gel permeation chromatography. Results from differential scanning calorimetry and X-ray diffraction studies indicated that within the terpolymer structure, the PCL segments are in the crystalline state, while fluorocarbon segments belong to the amorphous domains. Due to the thermodynamic incompatibility of PCL and PPFEMA, MCMs could be obtained upon aqueous self-assembly of the terpolymer. The well-segregated Janus-cores with adjustable compartment balance were revealed by transmission electron microscopy. In vitro cell viability assays further demonstrated an excellent cytocompatibility of the MCMs both in mouse embryonic fibroblasts (3T3) and human acute monocytic leukemia (THP-1) cells.

Biocompatibility and enhanced osteogenic differentiation of human mesenchymal stem cells in response to surface engineered poly(D,L-lactic-co-glycolic acid) microparticles

Tissue engineering strategies can be applied to enhancing osseous integration of soft tissue grafts during ligament reconstruction. Ligament rupture results in a hemarthrosis, an acute intra-articular bleed rich in osteogenic human mesenchymal stem cells (hMSCs). With the aim of identifying an appropriate biomaterial with which to combine hemarthrosis fluid-derived hMSCs (HF-hMSCs) for therapeutic application, this work has investigated the biocompatibility of microparticles manufactured from two forms of poly(D,L-lactic-co-glycolic acid) (PLGA), one synthesized with equal monomeric ratios of lactic acid to glycolic acid (PLGA 50:50) and the other with a higher proportion of lactic acid (PLGA 85:15) which confers a longer biodegradation time. The surfaces of both types of microparticles were functionalized by plasma polymerization with allylamine to increase hydrophilicity and promote cell attachment. HF-hMSCs attached to and spread along the surface of both forms of PLGA microparticle. The osteogenic response of HF-hMSCs was enhanced when cultured with PLGA compared with control cultures differentiated on tissue culture plastic and this was independent of the type of polymer used. We have demonstrated that surface engineered PLGA microparticles are an appropriate biomaterial for combining with HF-hMSCs and the selection of PLGA is relevant only when considering the biodegradation time for each biomedical application.

Poly(acrylic acid)-poly(ethylene glycol) nanoparticles designed for ophthalmic drug delivery

Poly(acrylic acid) (PAA) and poly(ethylene glycol) (PEG), four-arm, amine-terminated particles with nanometer size and spherical shape were obtained by the polymers cross-linking, via activation with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride, in a w/o emulsion. The morphology and surface charge of the final particles are strongly dependent on the molar ratio of PAA-PEG and the PAA concentration. The physicochemical characteristics correlated with the drug-loading capacity, in vitro and ex vivo release kinetics of pilocarpine hydrochloride and biocompatibility results indicate that these nanoparticles exhibit the prerequisite behavior for use as carriers of ophthalmic drugs.

Pharmacokinetics and in vivo biodistribution of optimized PLGA nanoparticulate drug delivery system for controlled release of emtricitabine

The objective of this study was to develop systematically optimized (OPT) nanoparticles (NPs) providing a controlled release using PLGA of emtricitabine (FTC) employing Formulation by Design (FbD), and evaluate their in vitro and in vivo performance. FTC generates severe adverse effects with risks of toxicity. Thus, NPs were prepared to reduce these drawbacks in this study. The NPs were prepared by water-in-oil-in-water (w/o/w) emulsion method, followed by high-pressure homogenization. The FTC NPs were systematically OPT using 3(2) central composite design and the OPT formulation located using overlay plot. The pharmacokinetics and in vivo biodistribution of OPT-FTC NPs were investigated in male Wistar rats via the oral administration. Transmission electron microscopy studies on OPT-FTC NPs demonstrated uniform shape and size of particles. In vitro release was sustained up to 15 days in PBS pH 7.4. Augmentation in the values of Cmax (1.63 fold) and AUC0-∞ (5.39 fold) indicated significant enhancement in the rate and extent of bioavailability by the OPT-FTC NPs compared to pure drug. OPT-FTC NPs showed 2.325 fold increase in the values of FTC concentrations in liver. The OPT-FTC NPs was found to be quite stable during 6 months of study period. Hence, the developed OPT-FTC NPs can be used as drug carrier for sustained/prolonged drug release and/or to reduce toxic effects.

Nanotechnology-based drug delivery systems and herbal medicines: a review

Herbal medicines have been widely used around the world since ancient times. The advancement of phytochemical and phytopharmacological sciences has enabled elucidation of the composition and biological activities of several medicinal plant products. The effectiveness of many species of medicinal plants depends on the supply of active compounds. Most of the biologically active constituents of extracts, such as flavonoids, tannins, and terpenoids, are highly soluble in water, but have low absorption, because they are unable to cross the lipid membranes of the cells, have excessively high molecular size, or are poorly absorbed, resulting in loss of bioavailability and efficacy. Some extracts are not used clinically because of these obstacles. It has been widely proposed to combine herbal medicine with nanotechnology, because nanostructured systems might be able to potentiate the action of plant extracts, reducing the required dose and side effects, and improving activity. Nanosystems can deliver the active constituent at a sufficient concentration during the entire treatment period, directing it to the desired site of action. Conventional treatments do not meet these requirements. The purpose of this study is to review nanotechnology-based drug delivery systems and herbal medicines.

Synthesis, characterization and bioevaluation of irinotecan-collagen hybrid materials for biomedical applications as drug delivery systems in tumoral treatments

The purpose of the present study is the preparation and characterization of collagen/antitumor drug hybrids as drug delivery systems. Materials used for obtaining collagen-based drug delivery systems were collagen type I (Coll) as matrix and irinotecan (I) as hydrophilic active substances. After incorporation of I into Coll in differing ratios, the obtained hybrid materials (Coll/I) could be used according to our results as potential drug delivery systems in medicine for the topical (local) treatment of cancerous tissues or bone. The released amount of I varies with amount of Coll from hybrid materials: the higher, the slower the release amount of irinotecan transferred is in the first 6 hours. The in vitro citotoxicity demonstrates an antitumoral activity of the obtained hybrid materials and their potential use for biomedical applications as drug delivery systems in tumoral treatments.

Ion-pair chromatography for simultaneous analysis of ethionamide and pyrazinamide from their porous microparticles

Ethionamide (ETA) and pyrazinamide (PZA) are considered the drugs of choice for the treatment of multidrug-resistant tuberculosis. Current methods available in the literature for simultaneous determination of ETA and PZA have low sensitivity or involve column modifications with lipophilic cations. The aim of this study was to develop a simple and validated reversed-phase ion-pair HPLC method for simultaneous determination of ETA and PZA for the characterization of polymeric-based porous inhalable microparticles in in vitro and spiked human serum samples. Chromatographic separation was achieved on a Phenomenex C18 column (250 mm × 4.6 mm) using a Shimadzu LC 10 series HPLC. The mobile phase consisted of A: 0.01% trifluoroacetic acid in distilled water and B: ACN/MeOH at 1:1 v/v. Gradient elution was run at a flow rate of 1.5 mL/min and a fixed UV wavelength of 280 nm. The validation characteristics included accuracy, precision, linearity, analytical range, and specificity. Calibration curves at seven levels for ETA and PZA were linear in the analytical range of 0.1-3.0 μg/mL with correlation coefficient of r (2) > 0.999. Accuracy for both ETA and PZA ranged from 94 to 106% at all quality control (QC) standards. The method was precise with relative standard deviation less than 2% at all QC levels. Limits of quantitation for ETA and PZA were 50 and 70 ng/mL, respectively. There was no interference from either the polymeric matrix ions or the biological matrix in the analysis of ETA and PZA.

Surface Engineered Poly(lactic acid) (PLA) Microspheres by Chemical Treatment for Drug Delivery System

Poly (lactic acid) (PLA) is well known for their biodegradability and bioresorbable properties and these properties made them suitable in drug delivery system as drug carriers. PLA is relatively hydrophobic and lack of cell-recognition group to interact with biologically active molecules which reduce the surface compatibility of microspheres. In this project, alkaline hydrolysis was used to induce hydrophilic functional group on the microspheres surface. Alkaline solution at 0.01M and 0.1M was used to modify microspheres surfaces. The engineered surfaces were evaluated using Scanning Electron Microscopy and Water Contact Angle. 0.1M alkaline solution hydrolyzed microspheres at higher extends as compared to 0.01M, where partial microspheres disintegrated and porous structure was revealed. The water contact angle of PLA films shows decreased from 65 ̊ to range 42 47 ̊ after alkaline hydrolysis.

Nanoparticulate flurbiprofen reduces amyloid-β42 generation in an in vitro blood-brain barrier model

INTRODUCTION

The amyloid-β42 (Aβ42) peptide plays a crucial role in the pathogenesis of Alzheimer's disease (AD), the most common neurodegenerative disorder affecting the elderly. Over the past years, several approaches and compounds developed for the treatment of AD have failed in clinical studies, likely in part due to their low penetration of the blood-brain barrier (BBB). Since nanotechnology-based strategies offer new possibilities for the delivery of drugs to the brain, this technique is studied intensively for the treatment of AD and other neurological disorders.

METHODS

The Aβ42 lowering drug flurbiprofen was embedded in polylactide (PLA) nanoparticles by emulsification-diffusion technique and their potential as drug carriers in an in vitro BBB model was examined. First, the cytotoxic potential of the PLA-flurbiprofen nanoparticles on endothelial cells and the cellular binding and uptake by endothelial cells was studied. Furthermore, the biological activity of the nanoparticulate flurbiprofen on γ-secretase modulation as well as its in vitro release was examined. Furthermore, the protein corona of the nanoparticles was studied as well as their ability to transport flurbiprofen across an in vitro BBB model.

RESULTS

PLA-flurbiprofen nanoparticles were endocytosed by endothelial cells and neither affected the vitality nor barrier function of the endothelial cell monolayer. The exposure of the PLA-flurbiprofen nanoparticles to human plasma occurred in a rapid protein corona formation, resulting in their decoration with bioactive proteins, including apolipoprotein E. Furthermore, luminally administered PLA-flurbiprofen nanoparticles in contrast to free flurbiprofen were able to modulate γ-secretase activity by selectively decreasing Aβ42 levels in the abluminal compartment of the BBB model.

CONCLUSIONS

In this study, we were able to show that flurbiprofen can be transported by PLA nanoparticles across an in vitro BBB model and most importantly, the transported flurbiprofen modulated γ-secretase activity by selectively decreasing Aβ42 levels. These results demonstrate that the modification of drugs via embedding in nanoparticles is a promising tool to facilitate drug delivery to the brain, which enables future development for the treatment of neurodegenerative disorders like AD.

Nanocapsules based on mPEGylated artesunate prodrug and its cytotoxicity

mPEGylated artesunate prodrug was synthesized via esterification between poly(ethylene glycol) monomethyl ether (mPEG) and artesunate (ART). The product was inclined to form nanocapsules in aqueous media due to its amphiphilic nature. These nanocapsules showed narrow size distribution, with an average particle size of 88.7 nm measured by dynamic laser scattering (DLS). Their vesical morphology was further confirmed by transmission electron microscopy (TEM). We found that the release of ART from the nanocapsules was controllable, which was contributed to the easily hydrolyzed property of the ester bond. In addition, the cytotoxicity of the prodrug against L1210 and MCF7 cell lines showed an essential decrease compared with the free ART. These results present a new strategy in designing anti-tumor ART nanocapsules for targeting tumor cells.

Dynamic in vivo imaging of dual-triggered microspheres for sustained release applications: synthesis, characterization and cytotoxicity study

This paper deals with the synthesis, characterization and property evaluation of drug-loaded magnetic microspheres with pH-responsive cross-linked polymer shell. The synthetic procedure consists of 3 steps, of which the first two comprise the synthesis of a poly methyl methacrylate (PMMA) template and the synthesis of a shell by using acrylic acid (AA) and methyl methacrylate (MMA) as monomers, and divinyl benzene (DVB) as cross-linker. The third step of the procedure refers to the formation of magnetic nanoparticles on the microsphere's surface. AA that attaches pH-sensitivity in the microspheres and magnetic nanoparticles in the inner and the outer surface of the microspheres, enhance the efficacy of this intelligent drug delivery system (DDS), which constitutes a promising approach toward cancer therapy. A number of experimental techniques were used to characterize the resulting microspheres. In order to investigate the in vitro controlled release behavior of the synthesized microspheres, we studied the Dox release percentage under different pH conditions and under external magnetic field. Hyperthermia caused by an alternating magnetic field (AFM) is used in order to study the doxorubicin (Dox) release behavior from microspheres with pH functionality. The in vivo fate of these hybrid-microspheres was tracked by labeling them with the γ-emitting radioisotope (99m)Tc after being intravenously injected in normal mice. According to our results, microsphere present a pH depending and a magnetic heating, release behavior. As expected, labeled microspheres were mainly found in the mononuclear phagocyte system (MPS). The highlights of the current research are: (i) to illustrate the advantages of controlled release by combining hyperthermia and pH-sensitivity and (ii) to provide noninvasive, in vivo information on the spatiotemporal biodistribution of these microsphere by dynamic γ-imaging.

Multifunctional biodegradable polymer nanoparticles with uniform sizes: generation and in vitro anti-melanoma activity

We present a simple, yet versatile strategy for the fabrication of uniform biodegradable polymer nanoparticles (NPs) with controllable sizes by a hand-driven membrane-extrusion emulsification approach. The size and size distribution of the NPs can be easily tuned by varying the experimental parameters, including initial polymer concentration, surfactant concentration, number of extrusion passes, membrane pore size, and polymer molecular weight. Moreover, hydrophobic drugs (e.g., paclitaxel (PTX)) and inorganic NPs (e.g., quantum dots (QDs) and magnetic NPs (MNPs)) can be effectively and simultaneously encapsulated into the polymer NPs to form the multifunctional hybrid NPs through this facile route. These PTX-loaded NPs exhibit high encapsulation efficiency and drug loading density as well as excellent drug sustained release performance. As a proof of concept, the A875 cell (melanoma cell line) experiment in vitro, including cellular uptake analysis by fluorescence microscope, cytotoxicity analysis of NPs, and magnetic resonance imaging (MRI) studies, indicates that the PTX-loaded hybrid NPs produced by this technique could be potentially applied as a multifunctional delivery system for drug delivery, bio-imaging, and tumor therapy, including malignant melanoma therapy.

Application of nanotechnology in improving bioavailability and bioactivity of diet-derived phytochemicals

Nanotechnology is an innovative approach that has potential applications in nutraceutical research. Phytochemicals have promising potential for maintaining and promoting health, as well as preventing and potentially treating some diseases. However, the generally low solubility, stability, bioavailability and target specificity, together with the side effects seen when used at high levels, have limited their application. Indeed, nanoparticles can increase solubility and stability of phytochemicals, enhance their absorption, protect them from premature degradation in the body and prolong their circulation time. Moreover, these nanoparticles exhibit high differential uptake efficiency in the target cells (or tissue) over normal cells (or tissue) through preventing them from prematurely interacting with the biological environment, enhanced permeation and retention effect in disease tissues and improving their cellular uptake, resulting in decreased toxicity, In this review, we outline the commonly used biocompatible and biodegradable nanoparticles including liposomes, emulsions, solid lipid nanoparticles, nanostructured lipid carriers, micelles and poly(lactic-co-glycolic acid) nanoparticles. We then summarize studies that have used these nanoparticles as carriers for epigallocatechin gallate, quercetin, resveratrol and curcumin administration to enhance their aqueous solubility, stability, bioavailability, target specificity and bioactivities.

Preparation of protamine cationic nanobubbles and experimental study of their physical properties and in vivo contrast enhancement

In this study, we aimed to prepare a novel type of microbubble (MB), protamine cationic nanobubble (NB), to provide a new vector for tumor gene therapy. We prepared cationic NBs with protamine and other lipid components using mechanical oscillation. The protamine cationic NBs had a mean diameter of 521.2 ± 37.57 nm, a zeta potential of +18.5 mV, and a gene-carrying capacity of 15.69 μg androgen receptor (AR) siRNA per 10(8) NBs. The cationic NBs exhibited superior contrast enhancement for in vivo imaging compared with SonoVue (Bracco, Geneva, Switzerland), and their physical properties did not change significantly after 1 wk; meanwhile, the transfection efficiency of the cationic NBs in androgen-independent prostate cancer cells mediated by ultrasound irradiation was better than that of liposomes (82.17 ± 7.4% vs. 55.04 ± 5.4%, p < 0.01). Therefore, the protamine cationic NB can be considered for use as a novel type of gene-loading MB for ultrasound imaging and MB-mediated gene therapy of tumors.

Basics and recent advances in peptide and protein drug delivery

While the peptide and protein therapeutic market has developed significantly in the past decades, delivery has limited their use. Although oral delivery is preferred, most are currently delivered intravenously or subcutaneously due to degradation and limited absorption in the gastrointestinal tract. Therefore, absorption enhancers, enzyme inhibitors, carrier systems and stability enhancers are being studied to facilitate oral peptide delivery. Additionally, transdermal peptide delivery avoids the issues of the gastrointestinal tract, but also faces absorption limitations. Due to proteases, opsonization and agglutination, free peptides are not systemically stable without modifications. This review discusses oral and transdermal peptide drug delivery, focusing on barriers and solutions to absorption and stability issues. Methods to increase systemic stability and site-specific delivery are also discussed.

Monocytes and macrophages as nanomedicinal targets for improved diagnosis and treatment of disease

The important role of monocytes and macrophages in diseases like cancer and atherosclerosis has started to get uncovered in the last decade. In addition, subsets of these cell types are believed to participate in the initiation and aggravation of several diseases including cancer and cardiovascular disease. For this reason, monocytes and macrophages have recently been identified as interesting targets for both diagnosis and treatment of the aforementioned pathologies. Compared with free therapeutic or imaging agents, nanoparticle formulations provide several advantages that improve the pharmacokinetics and bioavailability of these agents. In addition, the possibility of surface functionalization creates numerous ways to optimize nanoparticle delivery. Recent advances in nanomedicine have led to the development of multifunctional nanoparticles that allow simultaneous diagnosis and treatment of monocytes and macrophages with high specificity. Relying on the inherent ability of monocytes and macrophages to easily take up foreign particles, the use of nanoparticles provides a precious opportunity for the management of several inflammatory diseases.

Polymeric micelles with small lipophilic moieties for drug delivery

The aim of this study was to develop a new polymeric micelle delivery system for antitumor drugs. An amphiphile of methoxypoly(ethylene glycol)-histidine-di(cinnamic acid) (PEGHC) with a small lipophilic moiety instead of a hydrophobic biodegradable polymer chain was synthesized and characterized. The PEGHC self-assembled into micelles. The critical micelle concentration (CMC) was tested. 9-Nitro-20(s)-camptothecin (9-NC) was used as a model drug for encapsulation. The size and morphology of both blank and 9-NC loaded micelles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The release profile of 9-NC loaded micelles was studied. HepG2 liver cancer cells were incubated with the drug-loaded micelles to investigate the in vitro anticancer efficiency. The results showed that the 9-NC loaded micelles exhibited high accumulated release rate (>85%) and efficient in vitro anticancer activity.

Bioengineering strategies for designing targeted cancer therapies

The goals of bioengineering strategies for targeted cancer therapies are (1) to deliver a high dose of an anticancer drug directly to a cancer tumor, (2) to enhance drug uptake by malignant cells, and (3) to minimize drug uptake by nonmalignant cells. Effective cancer-targeting therapies will require both passive- and active-targeting strategies and a thorough understanding of physiologic barriers to targeted drug delivery. Designing a targeted therapy includes the selection and optimization of a nanoparticle delivery vehicle for passive accumulation in tumors, a targeting moiety for active receptor-mediated uptake, and stimuli-responsive polymers for control of drug release. The future direction of cancer targeting is a combinatorial approach, in which targeting therapies are designed to use multiple-targeting strategies. The combinatorial approach will enable combination therapy for delivery of multiple drugs and dual ligand targeting to improve targeting specificity. Targeted cancer treatments in development and the new combinatorial approaches show promise for improving targeted anticancer drug delivery and improving treatment outcomes.

Multifunctional nanoparticles for targeted delivery of immune activating and cancer therapeutic agents

Nanoparticles (NPs) have been extensively investigated for applications in both experimental and clinical settings to improve delivery efficiency of therapeutic and diagnostic agents. Most recently, novel multifunctional nanoparticles have attracted much attention because of their ability to carry diverse functionalities to achieve effective synergistic therapeutic treatments. Multifunctional NPs have been designed to co-deliver multiple components, target the delivery of drugs by surface functionalization, and realize therapy and diagnosis simultaneously. In this review, various materials of diverse chemistries for fabricating multifunctional NPs with distinctive architectures are discussed and compared. Recent progress involving multifunctional NPs for immune activation, anticancer drug delivery, and synergistic theranostics is the focus of this review. Overall, this comprehensive review demonstrates that multifunctional NPs have distinctive properties that make them highly suitable for targeted therapeutic delivery in these areas.

Characterisation, cytotoxicity and apoptosis studies of methotrexate-loaded PLGA and PLGA-PEG nanoparticles

Methotrexate (MTX) widely used in the treatments of various types of malignancies, but high toxicity and short plasma half-life have limited its use. This study was aimed at developing a polymeric drug delivery system for improving the therapeutic index of this potent drug. To achieve these goals, PLGA and PLGA-PEG nanoparticles were prepared using the emulsification-solvent diffusion technique and were optimized for particle size and entrapment efficiency. The optimum loaded nanoparticles were evaluated by cytotoxicity and their ability to induce apoptosis compared to free drug by examining of caspase-3 activity. The results showed that optimized particles were 182 ± 14 nm and 258 ± 10 nm in size for PLGA-PEG and PLGA nanoparticles, respectively, with an entrapment efficiency of more than 51%. The cytotoxicity experiment showed that the nanoparticles were more effective than pure MTX and increase the activity of caspase-3 in MCF7 and AGS and A549 cell lines.

Development and characterization of lecithin stabilized glibenclamide nanocrystals for enhanced solubility and drug delivery

Novel LNCs (lipid nanocrystals) were developed with an aim to improve the solubility, stability and targeting efficiency of the model drug glibenclamide (GLB). PEG 20000, Tween 80 and soybean lecithin were used as polymer, surfactant and complexing agent, respectively. GLB nanocrystals (NCs) were prepared by precipitation process and complexed using hot and cold melt technique. The LNCs were evaluated by drug loading, saturation solubility (SL), optical clarity, in vitro dissolution, solid state characterization, in vivo and stability analysis. LNCs exhibited a threefold increase in SL and a higher dissolution rate than GLB. The percentage dissolution efficiency was found to decrease with increase in PEG 20000. The average particle size was in the range of 155-842 nm and zeta potential values tend to increase after complexation. X-ray powder diffractometry and differential scanning calorimetry results proved the crystallinity prevailed in the samples. Spherical shaped particles (<1000 nm) with a lipid coat on the surface were observed in scanning electron microscopy analysis. Fourier transform infrared results proved the absence of interaction between drug and polymer and stability study findings proved that LNCs were stable. In vivo study findings showed a decrease in drug concentration to pancreas in male Wistar rats. It can be concluded that LNCs are could offer enhanced solubility, dissolution rate and stability for poorly water soluble drugs. The targeting efficiency of LNCs was decreased and further membrane permeability studies ought to be carried out.

Nanoparticles containing insoluble drug for cancer therapy

Nanoparticle drug formulations have been extensively researched and developed in the field of drug delivery as a means to efficiently deliver insoluble drugs to tumor cells. By mechanisms of the enhanced permeability and retention effect, nanoparticle drug formulations are capable of greatly enhancing the safety, pharmacokinetic profiles and bioavailability of the administered treatment. Here, the progress of various nanoparticle formulations in both research and clinical applications is detailed with a focus on the development of drug/gene delivery systems. Specifically, the unique advantages and disadvantages of polymeric nanoparticles, liposomes, solid lipid nanoparticles, nanocrystals and lipid-coated nanoparticles for targeted drug delivery will be investigated in detail.

Merging the best of both worlds: hybrid lipid-enveloped matrix nanocomposites in drug delivery

The advent of nanotechnology has revolutionized drug delivery in terms of improving drug efficacy and safety. Both polymer-based and lipid-based drug-loaded nanocarriers have demonstrated clinical benefit to date. However, to address the multifaceted drug delivery challenges ahead and further expand the spectrum of therapeutic applications, hybrid lipid-polymer nanocomposites have been designed to merge the beneficial features of both polymeric drug delivery systems and liposomes in a single nanocarrier. This review focuses on different classes of nanohybrids characterized by a drug-loaded polymeric matrix core enclosed in a lipid shell. Various nanoengineering approaches to obtain lipid-polymer nanocomposites with a core-shell nanoarchitecture will be discussed as well as their predominant applications in drug delivery.

Dual-functional nanoparticles targeting amyloid plaques in the brains of Alzheimer's disease mice

Alzheimer's disease (AD) is a common neurodegenerative disorder with few treatments. The limitations imposed by the blood-brain barrier (BBB) and the non-selective distribution of drugs in the brain have hindered the effective treatment of AD and may result in severe side effects on the normal brains. We developed a dual-functional nanoparticle drug delivery system based on a PEGylated poly (lactic acid) (PLA) polymer. Two targeting peptides that were screened by phage display, TGN and QSH, were conjugated to the surface of the nanoparticles. TGN specifically targets ligands at the BBB, while QSH has good affinity with Aβ(1-42), which is the main component of amyloid plaque. Tests probing the bEnd.3 cell uptake and in vivo imaging were conducted to determine the best density of TGN on the nanoparticles' surfaces. The optimal amount of QSH was studied using a Thioflavin T (ThT) binding assay and surface plasmon resonance (SPR) experiments. The optimal maleimide/peptide molar ratio was 3 for both TGN and QSH on the surface of the nanoparticles (T3Q3-NP), and these nanoparticles achieved enhanced and precise targeted delivery to amyloid plaque in the brains of AD model mice. A MTT assay also validated the safety of this dual-targeted delivery system; little cytotoxicity was demonstrated with both bEnd.3 and PC 12 cells. In conclusion, the T3Q3-NP might be a valuable targeting system for AD diagnosis and therapy.

Gelatin-based nanoparticles as drug and gene delivery systems: reviewing three decades of research

Gelatin is one of the most versatile natural biopolymers widely used in pharmaceutical industries due to its biocompatibility, biodegradability, low cost and numerous available active groups for attaching targeting molecules. These advantages led to its application in the synthesis of nanoparticles for drug and gene delivery during the last thirty years. The current article entails a general review of the different preparation techniques of gelatin nanoparticles (GNPs): desolvation, coacervation-phase separation, emulsification-solvent evaporation, reverse phase microemulsion, nanoprecipitation, self-assembly and layer-by-layer coating, from the point of view of the methodological and mechanistic aspects involved. Various crosslinkers used to improve the physicochemical properties of GNPs includintg aldehydes, genipin, carbodiimide/N-hydroxysuccinimide, and transglutaminase are reported. An analysis is given of the physicochemical behavior of GNPs including drug loading, release, particle size, zeta-potential, cytotoxicity, cellular uptake and stability. This review also attempts to provide an overview of the major applications of GNPs in drug delivery and gene therapy and their in vivo pharmacological performances, as well as site-specific drug targeting using various ligands modifying the surface of GNPs. Finally, nanocomplexes of gelatin with polymers, lipids or inorganic materials are also discussed.

Characterization of cross-linked gelatin nanoparticles by electrophoretic techniques in the liquid and the gas phase

Biodegradable nanoparticles (NPs) and hence e.g. NPs prepared from glutaraldehyde crosslinked gelatin (gelatin NPs) are lately receiving increased attention in various fields like pharmaceutical technology and nutraceutics as biocompatible carriers for hardly water soluble drugs, molecules intended for sustained release or targeted transport. However, in vivo application of such materials requires a thoroughly characterization of corresponding particles. In a previous manuscript we demonstrated the applicability of chip electrophoresis for the separation of gelatin NPs from NP building blocks. Following our previous results we intensified our efforts in the characterization of gelatin NPs by electrophoresis in the liquid (capillary and chip format) and the gas phase (gas phase electrophoretic mobility molecular analysis, GEMMA). In doing so, we demonstrated differences between nominally comparable (from the concentration of initially employed material for crosslinking) gelatin NP preparation batches concerning (i) the amount of obtained NPs, (ii) the degree of NP crosslinking, (iii) the amount of NP building blocks present within samples and (iv) the electrophoretic mobility diameter of NPs. Differences were even more pronounced when NP preparations from batches with different content of initially employed gelatin were compared. Additionally, we compared three setups for the removal of low molecular weight components from samples after fluorescence labeling of NPs. In overall, the combination of the three employed analytical methods for gelatin NP characterization - CE in the capillary and the chip format as well as GEMMA - allows a more thoroughly characterization of NP containing samples.

NEIMiner: nanomaterial environmental impact data miner

As more engineered nanomaterials (eNM) are developed for a wide range of applications, it is crucial to minimize any unintended environmental impacts resulting from the application of eNM. To realize this vision, industry and policymakers must base risk management decisions on sound scientific information about the environmental fate of eNM, their availability to receptor organisms (eg, uptake), and any resultant biological effects (eg, toxicity). To address this critical need, we developed a model-driven, data mining system called NEIMiner, to study nanomaterial environmental impact (NEI). NEIMiner consists of four components: NEI modeling framework, data integration, data management and access, and model building. The NEI modeling framework defines the scope of NEI modeling and the strategy of integrating NEI models to form a layered, comprehensive predictability. The data integration layer brings together heterogeneous data sources related to NEI via automatic web services and web scraping technologies. The data management and access layer reuses and extends a popular content management system (CMS), Drupal, and consists of modules that model the complex data structure for NEI-related bibliography and characterization data. The model building layer provides an advanced analysis capability for NEI data. Together, these components provide significant value to the process of aggregating and analyzing large-scale distributed NEI data. A prototype of the NEIMiner system is available at http://neiminer.i-a-i.com/.

Nanocarriers for intravenous injection--the long hard road to the market

Nanodispersed drug delivery systems for the intravenous injection have successfully overcome the hurdle of drug approval in the European Union and the United States. Although there is a need for highly advanced nanocarrier devices they have not been the result of a rational formulation design but were developed as stand-alone products in a long chain of case-by-case studies. This review focuses on aspects in development, composition, and manufacture of these innovative dosage forms that are relevant for the translation into new drug products.

Curcumin loaded poly(2-hydroxyethyl methacrylate) nanoparticles from gelled ionic liquid--in vitro cytotoxicity and anti-cancer activity in SKOV-3 cells

The main focus of this study is to encapsulate hydrophobic drug curcumin in hydrophilic polymeric core such as poly(2-hydroxyethyl methacrylate) [PHEMA] nanoparticles from gelled ionic liquid (IL) to improve its efficacy. We have achieved 26.4% drug loading in a biocompatible hydrophilic polymer. Curcumin loaded PHEMA nanoparticles (C-PHEMA-NPs) were prepared by nano-precipitation method. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis showed that the prepared nanoparticles were spherical in shape and free from aggregation. The size and zeta potential of prepared C-PHEMA-NPs were about 300 nm and -33.4 mV respectively. C-PHEMA-NPs were further characterized by FT-IR spectroscopy which confirmed the existence of curcumin in the nanoparticles. X-ray diffraction and differential scanning calorimetry studies revealed that curcumin present in the PHEMA nanoparticles were found to be amorphous in nature. The anticancer activity of C-PHEMA-NPs was measured in ovarian cancer cells (SKOV-3) in vitro, and the results revealed that the C-PHEMA-NPs had better tumor cells regression activity than free curcumin. Flow cytometry showed the significant reduction in G0/G1 cells after treatment with C-PHEMA-NPs and molecular level of apoptosis were also studied using western blotting. Toxicity of PHEMA nanoparticles were studied in zebrafish embryo model and results revealed the material to be highly biocompatible. The present study demonstrates the curcumin loaded PHEMA nanoparticles have potential therapeutic values in the treatment of cancer.