Model Drug Carriers Research Articles

Efficacy of copper nanoparticles encapsulated in soya lecithin liposomes in treating breast cancer cells (MCF-7) in vitro

Cancer is one of the leading causes of death, which has attracted the attention of the scientific world to the search for efficient methods for treatment. With the great development and regeneration of nanotechnology over the last 25 years, various nanoparticles in different structures, shapes and composites provide good potential for cancer therapy. There are several drugs approved by FDA used in breast cancer treatment like Cyclophosphamide, Doxorubicin Hydrochloride, Femara, Herceptin, etc. Each has several side effects as well as treatment, which limits the use of drugs due to heart failure, pulmonary dysfunction, or immunodeficiency. Recently, such side effects are greatly reduced by using innovative delivery techniques. Some drugs have been approved for use in cancer treatment under the concept of drug delivery, such as Doxil (liposomal loaded doxorubicin). The purpose of this study is to investigate the effect of copper nanoparticles (CuNPs) as a drug model for cancer treatment, either in their free form or encapsulated in Soy lecithin liposomes (SLP) from plant origin as a cheap source of lipids. CuNPs were prepared by the chemical reduction method and loaded onto SLP through the thin film hydration method. The drug model Cu/SLP was successfully combined. The characteristics of the free CuNPs, liposomes, and the combined form, zeta potential, size distribution, drug encapsulation efficiency (EE%), drug release profile, Fourier transform infrared (FTIR), and transmission electron microscopy (TEM), were checked, followed by an in vitro study on the breast cancer cell line Mcf-7 as a model for cytotoxicity evaluation. The optimal Cu/SLP had a particle mean size of 81.59 ± 14.93 nm, a negative zeta potential of − 50.7 ± 4.34 mV, loaded CuNPs showed an EE% of 78.9%, a drug release profile for about 50% of the drug was released after 6 h, and FTIR analysis was recorded. The cytotoxicity assay showed that the IC50 of Cu/SLP is smaller than that of free CuNPs. These results give clear evidence of the efficacy of using the combined Cu/SLP rather than CuNPs alone as a model drug carrier prepared from plant origin against cancer, both medically and economically.

Functionalization and higher-order organization of liposomes with DNA nanostructures

Small unilamellar vesicles (SUVs) are indispensable model membranes, organelle mimics, and drug and vaccine carriers. However, the lack of robust techniques to functionalize or organize preformed SUVs limits their applications. Here we use DNA nanostructures to coat, cluster, and pattern sub-100-nm liposomes, generating distance-controlled vesicle networks, strings and dimers, among other configurations. The DNA coating also enables attachment of proteins to liposomes, and temporal control of membrane fusion driven by SNARE protein complexes. Such a convenient and versatile method of engineering premade vesicles both structurally and functionally is highly relevant to bottom-up biology and targeted delivery.

Fabrication and characterization of electrospun κ-carrageenan based oral dispersible film with vitamin C

Oral dispersible films (ODF) are great alternatives to tablet medications as they will simply dissolve in the mouth. There are several ways to produce ODFs, but electrospinning is emerging as one of the best methods as it increases the surface to volume ratio which allows it to dissolve easily. ODFs are typically formulated using a combination of polymers to produce the necessary film qualities. The use of κ-carrageenan (κ-CAR), a natural polymer in ODFs are yet to be studied in detail. Therefore, this study aims to develop an ODF from a combination of κ-CAR, polyvinyl alcohol (PVA) and vitamin C, where the latter will act as a model drug carrier. 1.5w/v% κ-CAR and 14w/v% PVA at a ratio of 30:70 was added with different concentrations of vitamin C from 2 to 10w/v%, respectively. The resulting nanofibers were then examined for morphology, water contact angle (WCA) and disintegration time. All the solutions formed uniform nanofibers with an average diameter ranging from 190 to 490 nm and showed hydrophilic properties. Sample 4 showed the fastest disintegration time of 3.68 s and the lowest WCA of 38.5°. The results indicated that the best formulation for an ODF was with 8% vitamin C. The findings from this study provide promising groundwork for the use of κ-CAR as the biopolymer in combination with the PVA to develop a biopolymer-based ODF with vitamin C via electrospinning.

Spatially Resolved Correlation between Stiffness Increase and Actin Aggregation around Nanofibers Internalized in Living Macrophages.

Plasticity and functional diversity of macrophages play an important role in resisting pathogens invasion, tumor progression and tissue repair. At present, nanodrug formulations are becoming increasingly important to induce and control the functional diversity of macrophages. In this framework, the internalization process of nanodrugs is co-regulated by a complex interplay of biochemistry, cell physiology and cell mechanics. From a biophysical perspective, little is known about cellular mechanics’ modulation induced by the nanodrug carrier’s internalization. In this study, we used the polylactic-co-glycolic acid (PLGA)–polyethylene glycol (PEG) nanofibers as a model drug carrier, and we investigated their influence on macrophage mechanics. Interestingly, the nanofibers internalized in macrophages induced a local increase of stiffness detected by atomic force microscopy (AFM) nanomechanical investigation. Confocal laser scanning microscopy revealed a thickening of actin filaments around nanofibers during the internalization process. Following geometry and mechanical properties by AFM, indentation experiments are virtualized in a finite element model simulation. It turned out that it is necessary to include an additional actin wrapping layer around nanofiber in order to achieve similar reaction force of AFM experiments, consistent with confocal observation. The quantitative investigation of actin reconfiguration around internalized nanofibers can be exploited to develop novel strategies for drug delivery.

Formulation and characterization of curcumin loaded polymeric micelles produced via continuous processing.

A continuous processing platform was developed to produce polymeric micelles. A block copolymer of mPEG (5kD)-PCL (2kD) was used as the model drug carrier. The polymeric micelles were produced using an innovative co-axial turbulent jet with co-flow continuous technology to precisely control the physicochemical properties of the micelles. A 3×3×4 full factorial design of experiment (DoE) study was conducted to optimize the polymeric micelle processing to achieve the desired critical quality attributes such as particle size and polydispersity index (PDI). Curcumin was used as a hydrophobic model drug as polymeric micelles are traditionally used to improve solubility and chemical stability of hydrophobic drug molecules. A second DoE study was conducted to achieve maximal drug loading. The average size of the optimized curcumin-loaded polymeric micelles was 29.1±0.51 d.nm with a PDI value in the range of 0.05±0.02 and a maximum drug loading of 11.1±0.81% (w/w). When compared to polymeric micelles prepared using a manual ethanol injection method the particle size, PDI and drug loading for curcumin-loaded polymeric micelles was 74.8±8.68 d.nm, and 0.46±0.12 and 8.12±1.23%, respectively. These data show that the continuous processing method provided significant improvement in controlling the key quality attributes. The curcumin-loaded polymeric micelles exhibited a sustained release profile during dissolution of about 50% drug released in 12h compared to the free drug, which was completely released within 10h. The curcumin-loaded polymeric micelles were characterized for other key quality attributes such as critical micelle concentration (CMC), and morphology by transmission electron microscopy, X-ray powder crystallography, polarized light microscopy, and differential scanning calorimetry. A novel method for determining the CMC of the polymer was developed using dynamic light scattering (DLS). Curcumin-loaded polymeric micelles were further processed by lyophilization to prevent hydrolytic cleavage of the polymers and maintain long term stability. The current study highlighted the potential advantages of transitioning from manual batch processing to continuous processing and serves as an example of improving processing efficiency as well as product quality through utilization of advanced processing technologies.

SYNTHESIS AND STABILITY OF RESVERATROL-GOLD NANOPARTICLE-POLYETHYLENE GLYCOL-FOLIC ACID CONJUGATES

Objective: Gold nanoparticles (AuNPs) can be used as targeted drug delivery systems, however, AuNPs have high surface energy and easily aggregate,thus negatively impacting nanoparticle stability. Therefore, it is necessary to add a stabilizing agent to AuNPs. To synthesize AuNPs stabilized bypolyethylene glycol conjugated to folic acid (FA), thus creating a model drug (resveratrol [RSV]) carrier that targets FA receptors on cancer cells.Methods: AuNPs were synthesized using the Turkevich method and stabilized by adding FA conjugated to polyethylene glycol (PEG). After RSV wasloaded, the conjugate was physically characterized and subjected to stability tests.Results: The RSV-AuNP had an average particle size of 51.97 nm (polydispersity index [PDI] 0.694, zeta potential – 24.6 mV). The RSV-AuNP-PEG-FAconjugate (RSV-AuNP-PEG-FA) had an average particle size of 195.6 nm (PDI=0.233, zeta potential=−21.1 mV). Stability tests showed that RSV-AuNPPEG-FA was more stable than RSV-AuNP. Furthermore, RSV-AuNP-PEG-FA and RSV-AuNP were more stable in buffer pH 7.4 and bovine serum albumin2% than in buffer pH 4, cysteine 1%, and NaCl 0.9% solutions.Conclusion: PEG-FA conjugates can improve the stability of RSV-loaded AuNP.

Lipids alter microbial transport through intestinal mucus.

Mucus constitutes a protective layer which coats the gastrointestinal tract, controlling interactions of both commensal and pathogenic microbes with underlying tissues. Changes to the mucus barrier, for example due to altered mucin expression or external stimuli, may impact interactions with microbes and thus potentially contribute to altered gut homeostasis, onset of inflammation, or pathogen invasion. Food-associated stimuli, including lipids, have been shown to change mucus barrier properties and reduce transport of model drug carriers through mucus. Here, we explore the impact of lipids, specifically triglycerides in a model intestinal medium mimicking a fed state, on Escherichia coli (E. coli) transport through mucus by directly imaging swimming patterns and analyzing associated changes in mucus structure. Lipids in model fed state intestinal contents reduced E. coli speed and track linearity within mucus. These changes may be due in part to changes in molecular interactions within the mucus network as well as crowding of the mucus network by lipid emulsion droplets, which visibly stay intact in the mucus gel. In addition, observed physical interactions between bacteria and lipid structures may impact microbial speed and trajectories. As lipids are normal food components and thus represent safe, mild stimuli, these results support exploration of lipid-based strategies to alter the mucus barrier to control interactions with microbes and potentially prevent microbial invasion of underlying epithelium.

PEGylation of model drug carriers enhances phagocytosis by primary human neutrophils

Targeted drug carriers are attractive for the delivery of therapeutics directly to the site of a disease, reducing systemic side effects and enhancing the efficacy of therapeutic molecules. However, the use of particulate carriers for drug delivery comes with its own set of challenges and barriers. Among these, a great deal of research effort has focused on protecting carriers from clearance by phagocytes via altering carrier surface chemistry, mostly with the use of polyethylene glycol (PEG) chain coatings. However, few papers have explored the effects of PEGylation on uptake by freshly-obtained primary human phagocytes in physiological conditions. In this work, we investigate the effect of PEGylation on particle uptake by primary human neutrophils in vitro and compare these effects to several cell lines and other model phagocytic cells systems. We find that human neutrophils in whole blood preferentially phagocytose PEGylated particles (e.g., ∼40% particle positive neutrophils for PEGylated versus ∼20% for carboxylated polystyrene microspheres) and that this effect is linked to factors present in human plasma. Model phagocytes internalized PEGylated particles less efficiently or equivalently to carboxylated particles in culture medium but preferentially phagocytosed PEGylated particles in the human plasma (e.g., ∼86% versus ∼63% PEGylated versus carboxylated particle positive cells, respectively). These findings have significant implications for the efficacy of PEGylation in designing long-circulating drug carriers, as well as the need for thorough characterization of drug carrier platforms in a wide array of in vitro and in vivo assays. Statement of SignificanceThe work in this manuscript is highly significant to the field of drug delivery, as it explores in-depth the effects of polyethylene glycol (PEG) coatings, which are frequently used to prevent phagocytic clearance of particulate drug carriers, on the phagocytosis of such carriers by neutrophils, the most abundant leukocyte in blood circulation. Surprisingly, we find that PEGylation enhances uptake by primary human neutrophils, specifically in the presence of human plasma. This result suggests that PEGylation may not confer the benefits in humans once thought, and may help to explain why PEG has not become the “magic bullet” it was once thought to be in the field of particulate drug delivery.

Interactions of polymeric drug carriers with DDT reduce their combined cytotoxicity

Attention has been paid to the environmental distribution and fate of nanomedicines. However, their effects on the toxicity of environmental pollutants are lack of knowledge. In this study, the negatively charged poly (ethylene glycol)-b-poly (L-lactide-co-glycolide) (mPEG-PLA) and positively charged polyethyleneimine-palmitate (PEI-PA) nanomicelles were synthesized and served as model drug carriers to study the interaction and combined toxicity with dichlorodiphenyltrichloroethane (DDT). DDT exerted limited effect on the biointerfacial behavior of mPEG-PLA nanomicelles, whereas it significantly mitigated the attachment of PEI-PA nanomicelles on the model cell membrane as monitored by quartz crystal microbalance with dissipation (QCM-D). The cytotoxicity of DDT towards NIH 3T3 cells was greatly decreased by either co-treatment or pre-treatment with the nanomicelles according to the results of real-time cell analysis (RTCA). The cell viability of NIH 3T3 exposed to DDT was increased up to 90% by the co-treatment with mPEG-PLA nanomicelles. Three possible reasons were proposed: (1) decreased amount of free DDT in the cell culture medium due to the partitioning of DDT into nanomicelles; (2) mitigated cellular uptake of nanomicelle-DDT complexes due to the complex agglomeration or electrostatic repulsion between complexes and cell membrane; (3) detoxification effect in the lysosome upon endocytosis of nanomicelle-DDT complexes.

Natural material-decorated mesoporous silica nanoparticle container for multifunctional membrane-controlled targeted drug delivery.

To avoid the side effects caused by nonspecific targeting, premature release, weak selectivity, and poor therapeutic efficacy of current nanoparticle-based systems used for drug delivery, we fabricated natural material-decorated nanoparticles as a multifunctional, membrane-controlled targeted drug delivery system. The nanocomposite material coated with a membrane was biocompatible and integrated both specific tumor targeting and responsiveness to stimulation, which improved transmission efficacy and controlled drug release. Mesoporous silica nanoparticles (MSNs), which are known for their biocompatibility and high drug-loading capacity, were selected as a model drug container and carrier. The membrane was established by the polyelectrolyte composite method from chitosan (CS) which was sensitive to the acidic tumor microenvironment, folic acid-modified CS which recognizes the folate receptor expressed on the tumor cell surface, and a CD44 receptor-targeted polysaccharide hyaluronic acid. We characterized the structure of the nanocomposite as well as the drug release behavior under the control of the pH-sensitive membrane switch and evaluated the antitumor efficacy of the system in vitro. Our results provide a basis for the design and fabrication of novel membrane-controlled nanoparticles with improved tumor-targeting therapy.

Margination of Fluorescent Polylactic Acid–Polyaspartamide based Nanoparticles in Microcapillaries In Vitro: the Effect of Hematocrit and Pressure

The last decade has seen the emergence of vascular-targeted drug delivery systems as a promising approach for the treatment of many diseases, such as cardiovascular diseases and cancer. In this field, one of the major challenges is carrier margination propensity (i.e., particle migration from blood flow to vessel walls); indeed, binding of these particles to targeted cells and tissues is only possible if there is direct carrier–wall interaction. Here, a microfluidic system mimicking the hydrodynamic conditions of human microcirculation in vitro is used to investigate the effect of red blood cells (RBCs) on a carrier margination in relation to RBC concentration (hematocrit) and pressure drop. As model drug carriers, fluorescent polymeric nanoparticles (FNPs) were chosen, which were obtained by using as starting material a pegylated polylactic acid–polyaspartamide copolymer. The latter was synthesized by derivatization of α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) with Rhodamine (RhB), polylactic acid (PLA) and then poly(ethyleneglycol) (PEG) chains. It was found that the carrier concentration near the wall increases with increasing pressure drop, independently of RBC concentration, and that the tendency for FNP margination decreases with increasing hematocrit. This work highlights the importance of taking into account RBC–drug carrier interactions and physiological conditions in microcirculation when planning a drug delivery strategy based on systemically administered carriers.

Determination of the composition, encapsulation efficiency and loading capacity in protein drug delivery systems using circular dichroism spectroscopy

Peptides and proteins have become very promising drug candidates in recent decades due to their unique properties. However, the application of these drugs has been limited by their high enzymatic susceptibility, low membrane permeability and poor bioavailability when administered orally. Considerable efforts have been made to design and develop drug delivery systems that could transport peptides and proteins to targeted area. Although it is of great importance to determine the composition after loading a drug to the carrier, the ability to do so is significantly limited by current analytical methods. In this letter, five important proteins, α1-antitrypsin, hemoglobin human, human serum albumin, human transferrin and r-globulin were chemically conjugated to two model drug carriers, namely carbon dots and polymer O-(2-carboxyethyl) polyethylene glycol. A simple yet convenient method based on circular dichroism spectroscopy was developed to determine the compositions of the various protein-carrier conjugates.

Engineering red‐blood‐cell‐membrane–coated nanoparticles for broad biomedical applications

R ed blood cells (RBCs) are nature’s long-circulating delivery vehicles. They possess various remarkable properties and continue to inspire the design and engineering of man-made delivery systems. Inherently suited for intravascular delivery, RBCs are intrinsically biocompatible, biodegradable, and nonimmunogenic. They form natural compartments capable of protecting encapsulated cargos, and this allows them to circulate in the bloodstream for a long period of time (up to 120 days). In addition, their semipermeable membrane affords sustained release to smallmolecule drugs, yet they are ideal for retaining large proteins while providing them access to the substrates. Delivery vehicles possessing one or several of these properties have long been desired for efficacious therapeutics. A long-sought strategy for RBC-mimicking delivery vehicles is to load natural RBCs with therapeutic agents without compromising the structural integrity and biological functions of the RBCs. Various loading techniques, including automated loading devices, have been developed to enable the encapsulation of payloads with molecular weights of over 180 kDa into RBCs with maintenance of the carriers’ biological competence. In addition to the interior of RBCs, their exterior surface has also been coupled with therapeutic molecules, either covalently or physically, for various delivery applications. These RBC-based delivery vehicles, namely carrier RBCs, have been developed for the delivery of numerous therapeutic agents, including proteins, nucleic acids, and small-molecule drugs. Several of them have entered clinical tests to treat various diseases, including cancers and enzyme deficiencies. Meanwhile, advances in molecular biology have provided unprecedented understanding of the connections between the physicochemical characteristics of RBCs and their biological functions. This understanding, in turn, has inspired researchers to model drug carriers after RBCs. Designs that mimic the physicochemical characteristics and biological functions of RBCs, particularly those that enable their passage through narrow constrictions while maintaining a long in vivo survival, have been integrated into the engineering of drug carriers and have resulted in novel delivery systems with improved drug tolerability, circulation lifetime, and efficacy. Recently, the pursuit of RBC-mimicking nanoparticles led us to develop an intriguing approach for functionalizing synthetic nanoparticles with natural RBC membranes. In this approach, we first collected intact cellular membranes and then coated them onto polymeric nanoparticle cores, such as those made from poly(lactic-co-glycolic acid) (PLGA); this resulted in red-blood-cell-membrane–coated nanoparticles (RBC-NPs; Figure 1). Our aim was to fabricate cellmimicking nanoparticles through a top-down approach that bypassed the labor-intensive processes of protein identification, purification, and conjugation. The natural membranes also provide a bilayered medium for transmembrane protein anchorage while preventing common chemical modifications that could compromise the integrity and functionalities of these proteins. The independent preparation of cellular membranes and particle cores before coating offers a new level of engineering flexibility toward highly functional biomimetic nanoparticles. Since their initial development, RBC-NPs have provided an unprecedented capability for harnessing the natural functionalities of native cells that would otherwise be difficult to replicate. They have since inspired us to develop novel nanotherapeutics for better disease intervention. In this Perspective, we review our recent progress in developing RBC-NPs for three distinct biomedical applications: long-circulating nanocarriers for drug delivery, biomimetic nanosponges for detoxification, and nanotoxoids for safe and effective toxin vaccination.

Evaluation of sub-micron, ultrasound-responsive particles as a drug delivery strategy

Substantial portions of tumors are largely inaccessible to drugs due to their irregular vasculature and high intratumoral pressure. The enhanced permeability and retention effect causes drug carriers within the size range of 100–800 nm to passively accumulate within tumors; however, they remain localized close to the vasculature. Failure to penetrate into and throughout the tumor ultimately limits treatment efficacy. Ultrasound-induced cavitation events have been cited as a method of stimulating greater drug penetration. At present, this targeting strategy is limited by the difference in size between the nano-scale drug carriers used and the cavitation nuclei available, i.e., the micron-scale contrast agent SonoVue. In vivo this results in spatial separation of the two agents, limiting the capacity for one to impact upon the other. Our group has successfully formulated two different monodisperse suspensions of nanoparticles that are of a size that will permit better co-localization of cavitation nuclei and therapeutics. A mixture of these nanoparticles and a model drug carrier were passed through a tissue mimicking phantom to provide an in vitro simulation of flow through a tumor. The impact of ultrasound on the penetration of drug carrier from the flow channel was compared between both of our ultrasound-responsive particles and SonoVue.

Gold nanoparticles regulate the blimp1/pax5 pathway and enhance antibody secretion in B-cells

Nanoparticles are potential threats to human health and the environment; however, their medical applications as drug carriers targeting cancer cells bring hope to contemporary cancer therapy. As a model drug carrier, gold nanoparticles (GNPs) have been investigated extensively for in vivo toxicity. The effect of GNPs on the immune system, however, has rarely been examined. Antibody-secreting cells were treated with GNPs with diameters ranging from 2 to 50 nm. The GNPs enhanced IgG secretion in a size-dependent manner, with a peak of efficacy at 10 nm. The immune-stimulatory effect reached a maximum at 12 h after treatment but returned to control levels 24 h after treatment. This enhancing effect was validated ex vivo using B-cells isolated from mouse spleen. Evidence from RT-PCR and western blot experiments indicates that GNP-treatment upregulated B-lymphocyte-induced maturation protein 1 (blimp1) and downregulated paired box 5 (pax5). Immunostaining for blimp1 and pax5 in B-cells confirmed that the GNPs stimulated IgG secretion through the blimp1/pax5 pathway. The immunization of mice using peptide-conjugated GNPs indicated that the GNPs were capable of enhancing humoral immunity in a size-dependent manner. This effect was consistent with the bio-distribution of the GNPs in mouse spleen. In conclusion, in vitro, ex vivo, and in vivo evidence supports our hypothesis that GNPs enhance humoral immunity in mouse. The effect on the immune system should be taken into account if nanoparticles are used as carriers for drug delivery. In addition to their toxicity, the immune-stimulatory activity of nanoparticles could play an important role in human health and could have an environmental impact.

P-glycoprotein-dependent trafficking of nanoparticle-drug conjugates.

P-glycoprotein (P-gp) is considered to be the most prevalent and single most important cause of multidrug-resistance (MDR) in humans. Although the protein is well known to modulate the cellular trafficking of small molecule fluorophores, antimicrobials, and up to 50% of all cytotoxic chemotherapeutics, little is known about its interactions with nanoscale drug conjugates. Here, we use P-gp substrate-conjugated gold nanorods as model drug carriers to investigate P-gp-dependent cellular trafficking of nanoparticles.

Binding behaviour and solubilisation of p-sulfonatocalixarenes to cinchona alkaloids

In this study, we investigated the binding behaviours of three water-soluble p-sulfonatocalixarenes with four cinchona alkaloids in aqueous and phosphate buffer solutions (pH 7.2 and 2.0). The complexation stability constants obtained by fluorescence titrations were comparatively discussed from several aspects: host cavity, pH effect and ionic strength. Among three hosts, p-sulfonatocalix[4]arene (SC4A) forms the most stable complexes with cinchona alkaloids, especially in acidic aqueous conditions. Furthermore, SC4A was elected as model drug carrier for cinchona alkaloids, where solubilisation by the complexation of SC4A and mimic release from the calixarene cavity in the presence of negatively charged micelles were initially studied.

Effects of nanoparticles in cells infected by Toxoplasma gondii

AbstractCore-shell model drug carriers on 2 nanoscale size levels have been applied in cell culture studies, focused on Toxoplasmosis therapy. In synthesis, a seed of Rhodamin B-labelled polystyrene latex particles was coated by polybutyl cyanoacrylate under physical inclusion of 2 different, new drugs against Toxoplasmosis. Drug-loaded as well as drug-free core-shell model drug carriers were added to a cell culture of human macrophages, infected by Toxoplasma gondii, following an infection plan. Drug release from the carriers had been studied before by enzymatic degradation by means of pork liver esterase. Particle size decrease by degradation was investigated in a UV/VIS spectrometer via transmission measurements. Drug release profiles were obtained by HPLC studies. The dynamics in the population of infected human macrophages, Toxoplasma gondii as well as model drug carrier numbers were registered by a FACS (fluorescence-activated cell sorter). As main result, the drug-free references in the 2 series of core-shell model drug carriers achieved ca.85% of the observed maximum in Toxoplasmosis therapy efficiency. These data were correlated with an immune stimulant effect on the side of the human macrophages, caused by the cell uptake of colloidal substrate, foreign to the body.

Comparison between Microplate Spectrometry and LC/MS Chromato-graphy for Facile Pilot Pharmacokinetics and Biodistribution Studies of Doxorubicin-loaded Nanoparticle Drug Carriers

Article history: Received on: 07/09/2012 Revised on: 18/09/2012 Accepted on: 22/09/2012 Available online: 28/09/2012 A facile and reliable method to perform pilot pharmacokinetic (PK) and biodistribution studies is necessary for expediting the overall development and clinical translation of novel nanoparticle drug carriers. In this study, we compared two common analytical techniques, fluorescence spectrometry using a microplate reader and liquid chromatography/mass spectrometry (LC/MS), demonstrating the quantification of a model anticancer drug (doxorubicin: DOX) in its free drug and nanoparticle formulations in vivo. Drug-loaded nanoparticle formulations were prepared from poly(ethylene glycol)-poly(aspartate) block copolymers, which formed two model drug carriers with different particle stability, self-assembled polymer micelles (DOX-micelles) and cross-linked nanoassemblies (DOX-CNAs). These three DOX formulations were injected into tumor-bearing mice at a DOX equivalent concentration. DOX levels in liver, spleen, and tumors were found to be comparable regardless of the analytical methods. LC/MS showed lower serum level than spectrometry with a microplate reader, which is consistent with the fact that DOX metabolites are present mainly in the serum.These results demonstrate that, in comparison to the LC/MS method, spectrometry using a microplate reader would be a viable and more facile method to perform pilot PK and biodistribution studies of various potential nanoparticle drug carriers using DOX as a model drug. Kay words: Drug Delivery, Polymer Micelles, Cross-linked Nanoassemblies, Doxorubicin, Pharmacokinetics, Biodistribution

The effect of blending time on particle adhesion in a model interactive system.

The adhesive tendency of drug particles in a model drug carrier interactive system increased with blending time. The degree of interaction was measured using a centrifuge technique; the resultant adhesion profile of per cent retained on the carrier versus the square of the speed of rotation was a logarithmic normal function that allowed the determination of the S50 to characterize the adhesion tendency. The relative degree of adhesion of the drug particles in the interactive mixtures and the rate to attain adhesion saturation in the interactive system during the mixing process was markedly different for the three mixtures studied. The increased adhesive tendencies during blending were probably associated with triboelectrification of the drug and carrier particles.