Methotrexate-loaded chitosan- and glycol chitosan-based nanoparticles: a promising strategy for the administration of the anticancer drug to brain tumors

A review of chitosan-based nanocarriers as drug delivery systems for brain diseases: Critical challenges, outlooks and promises

The administration of medicinal drugs orally or systemically limits the treatment of specific central nervous system (CNS) illnesses, such as certain types of brain cancers. These methods can lead to severe adverse reactions and inadequate transport of drugs to the brain, resulting in limited effectiveness. The CNS homeostasis is maintained by various barriers within the brain, such as the endothelial, epithelial, mesothelial, and glial barriers, which strictly control the movement of chemicals, solutes, and immune cells. Brain capillaries consist of endothelial cells (ECs) and perivascular pericytes, with pericytes playing a crucial role in maintaining the blood-brain barrier (BBB), influencing new blood vessel formation, and exhibiting secretory capabilities. This article summarizes the structural components and anatomical characteristics of the BBB. Intranasal administration, a non-invasive method, allows drugs to reach the brain by bypassing the BBB, while direct cerebral administration targets specific brain regions with high concentrations of therapeutic drugs. Technical and mechanical tools now exist to bypass the BBB, enabling the development of more potent and safer medications for neurological disorders. This review also covers clinical trials, formulations, challenges, and patents for a comprehensive perspective.

Diruthenium(II-III)-ibuprofen-loaded chitosan-based microparticles and nanoparticles systems: encapsulation, characterisation, anticancer activity of the nanoformulations against U87MG human glioma cells

The aim of this work was to investigate novel formulations containing diruthenium(II-III)-ibuprofen (RuIbp) metallodrug encapsulated into the chitosan (CT) biopolymer. Microparticles (RuIbp/CT MPs, ∼ 1 µm) were prepared by spray-drying, and RuIbp/CT-crosslinked nanoparticles (NPs) by ionic gelation (RuIbp/CT-TPP, TPP = tripolyphosphate (1), RuIbp/CT-TPP-PEG, PEG = poly(ethyleneglycol (2)) or pre-gel/polyelectrolyte complex method (RuIbp/CT-ALG, ALG = alginate (3)). Ru analysis was conducted by energy dispersive x-ray fluorescence or inductively coupled plasma atomic emission spectroscopy, and physicochemical characterisation by powder x-ray diffraction, electronic absorption and FTIR spectroscopies, electrospray ionisation mass spectrometry, thermal analysis, scanning electron, transition electron and atomic force microscopies, and dynamic light scattering. The RuIbp-loaded nanosystems exhibited encapsulation efficiency ∼ 20-37%, drug loading∼ 10-20% (w/w), hydrodynamic diameter (nm): 103.2 ± 7.9 (1), 91.7 ± 12.6 (2), 270.2 ± 58.4 (3), zeta potential (mV): +(47.7 ± 2.8) (1), +(49.2 ± 3.6) (2), -(28.2 ± 2.0) (3). Nanoformulation (1) showed the highest cytotoxicity with increased efficacy in relation to the RuIbp free metallodrug against U87MG human glioma cells.

Vesicles of yeast cell wall-sitagliptin to alleviate neuroinflammation in Alzheimer's disease

A cell-based drug delivery system based on yeast-cell wall loaded with sitagliptin, a drug with an anti-inflammatory effect, was developed to control neuroinflammation associated with Alzheimer's disease. The optimized nanoparticles had a spherical shape with a negative surface charge, and were shown to be less toxic than the carrier and sitagliptin. Moreover, the nanoparticles caused anti-inflammatory effects against tumor necrosis factor-alpha in mice model of neuroinflammation. The pharmacokinetics study showed the brain concentration of drug in the nanoparticles group was much higher than in the control group. To evaluate the effect of P-glycoprotein on brain entry of sitagliptin, the experiment was repeated with verapamil, as a P-glycoprotein inhibitor. Brain concentration of the nanoparticles group remained approximately unchanged, proving the "Trojan Horse" effect of the developed nanocarriers. The results are promising for using yeast-cell wall as a carrier for targeted delivery to immune cells for the management of inflammation.

Naturally occurring, natural product inspired and synthetic heterocyclic anti-cancer drugs

This chapter describes the importance and activity of a huge number of commercially available naturally occurring, natural product derived or synthetic heterocyclic anti-cancer drugs.

Ellagic acid-loaded, tween 80-coated, chitosan nanoparticles as a promising therapeutic approach against breast cancer: In-vitro and in-vivo study

AIMS

Among polyphenolic phytoconstituents with anticancer properties, Ellagic acid (EA) is widely reported for its translational potential in vitro but efficient in vivo delivery of EA has been a challenge. We, for the first time, used a tween 80 coated nano delivery of Ellagic acid to evaluate its preclinical efficacy in vitro and in vivo for breast cancer.

MAIN METHODS

To overcome the challenges of in vivo delivery, two batches of chitosan-based nanoformulations of EA (with and without tween 80 coating) were prepared by the ionotropic gelation method. The nanoformulations were characterized and further evaluated in vitro against breast cancer cells (MCF7) and in vivo with EAC tumor-bearing mice for establishing their anticancer efficacy compared to Ellagic acid alone. A quantitative simulation study was undertaken to understand if the observed antitumor efficacy is due to the synergistic efficacy of the Chitosan-Ellagic acid combination.

KEY FINDINGS

Results revealed that nanoformulations consist of good nano-sized encapsulation of EA and showed good drug entrapment-release capacity. Nano-encapsulated EA is biocompatible and exhibited higher cytotoxicity in vitro compared to EA alone. Similarly, significantly higher tumor regression was observed in nano-EA treated mice compared to EA alone, and best efficacy was observed with the nanoformulation with tween 80 coating. Furthermore, nanoformulations showed higher apoptosis in tumor tissues with no significant tissue toxicity in vital organs.

SIGNIFICANCE

We report synergism of Chitosan-Ellagic acid combination in the tween 80 coated nanoparticles of Ellagic acid resulting in enhanced anti-breast tumor efficacy that may be of translational value for other tumor types, too.

Enhanced Cytotoxic Effect of Doxorubicin Conjugated to Glutathione-Stabilized Gold Nanoparticles in Canine Osteosarcoma-In Vitro Studies

Osteosarcoma (OSA) is the most common malignant bone neoplasia in humans and dogs. In dogs, treatment consists of surgery in combination with chemotherapy (mostly carboplatin and/or doxorubicin (Dox)). Chemotherapy is often rendered ineffective by multidrug resistance. Previous studies have revealed that Dox conjugated with 4 nm glutathione-stabilized gold nanoparticles (Au-GSH-Dox) enhanced the anti-tumor activity and cytotoxicity of Dox in Dox-resistant feline fibrosarcoma cell lines exhibiting high P-glycoprotein (P-gp) activity. The present study investigated the influence of Au-GSH-Dox on the canine OSA cell line D17 and its relationship with P-gp activity. A human Dox-sensitive OSA cell line, U2OS, served as the negative control. Au-GSH-Dox, compared to free Dox, presented a greater cytotoxic effect on D17 (IC₅₀ values for Au-GSH-Dox and Dox were 7.9 μg/mL and 15.2 μg/mL, respectively) but not on the U2OS cell line. All concentrations of Au-GSH (ranging from 10 to 1000 μg/mL) were non-toxic in both cell lines. Inhibition of the D17 cell line with 100 μM verapamil resulted in an increase in free Dox but not in intracellular Au-GSH-Dox. The results indicate that Au-GSH-Dox may act as an effective drug in canine OSA by bypassing P-gp.

Microfluidic platform for synthesis and optimization of chitosan-coated magnetic nanoparticles in cisplatin delivery

In this study, magnetic core/chitosan shell Nanoparticles (NPs) containing cisplatin were synthesized via cisplatin complexation with tripolyphosphate as the chitosan crosslinker using two different procedures: a conventional batch flow method and a microfluidic approach. An integrated microfluidic device composed of three stages was developed to provide precise and highly controllable mixing. The comparison of the results revealed that NPs synthesized in microchannels were monodisperse 104 ± 14.59 nm (n = 3) in size with optimal morphological characteristics, whereas polydisperse 423 ± 53.33 nm (n = 3) nanoparticles were obtained by the conventional method. Furthermore, cisplatin was loaded in NPs without becoming inactivated, and the microfluidic technique demonstrated higher encapsulation efficiency, controlled release, and consequently lower IC50 values during exposure to the A2780 cell line proving that microfluidic synthesized NPs were able to enter the cells and release the drug more efficiently. The developed microfluidic platform presents valuable features that could potentially provide the clinical translation of NPs in drug delivery.

Development of an albumin decorated lipid-polymer hybrid nanoparticle for simultaneous delivery of methotrexate and conferone to cancer cells

Aiming to simultaneous target of methotrexate (MTX), as folate antagonist, and conferone (CON) in various cancer cells, the newly lipid/polymer hybrid nanoparticle containing an albumin targeted succinylchitosan shell and lipoid bilayer core composed of hydrogenated soy phosphatidylcholine and cholesterol was synthesized. The covalently conjugating albumin to the external surface of chitosan was accomplished using N-(3-Dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride and N- hydroxyl succinimide as an activating carboxylic group, and nanoliposomes were fabricated via thin film hydration-sonication method. The molecular structure of MTX@CON-targeted lipid/polymer hybrid nanoparticle (MTX@CON-TLPN) were characterized using FTIR spectroscopy, ¹H NMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The newly nanoparticle with high encapsulation efficiency (85.12%, and 78.4%), acceptable loading capacity (9.8% and 4.6% for MTX and CON) and the stimuli responsiveness drug release behavior in simulated physiologic tumor tissue condition (pH 5.4, 40 °C) was successfully synthetized in the spherical shape with mean average size of approximately 290 nm and ζ-potential of +21 mv. The enhanced efficiency of the targeted nanoparticle was further confirmed using MTT endpoints, cell cycle modulation, apoptosis assessment, and cellular internalization assessments. Collectively, these findings establish the utility of our newly prepared nanoparticle for simultaneous delivery of multiple anti-cancer drugs.

Overcoming the Blood-Brain Barrier: Functionalised Chitosan Nanocarriers

The major impediment to the delivery of therapeutics to the brain is the presence of the blood-brain barrier (BBB). The BBB allows for the entrance of essential nutrients while excluding harmful substances, including most therapeutic agents; hence, brain disorders, especially tumours, are very difficult to treat. Chitosan is a well-researched polymer that offers advantageous biological and chemical properties, such as mucoadhesion and the ease of functionalisation. Chitosan-based nanocarriers (CsNCs) establish ionic interactions with the endothelial cells, facilitating the crossing of drugs through the BBB by adsorptive mediated transcytosis. This process is further enhanced by modifications of the structure of chitosan, owing to the presence of reactive amino and hydroxyl groups. Finally, by permanently binding ligands or molecules, such as antibodies or lipids, CsNCs have showed a boosted passage through the BBB, in both in vivo and in vitro studies which will be discussed in this review.

Biomedical and Pharmacological Uses of Fluorescein Isothiocyanate Chitosan-Based Nanocarriers

Chitosan-based nanocarriers (ChNCs) are considered suitable drug carriers due to their ability to encapsulate a variety of drugs and cross biological barriers to deliver the cargo to their target site. Fluorescein isothiocyanate-labeled chitosan-based NCs (FITC@ChNCs) are used extensively in biomedical and pharmacological applications. The main advantage of using FITC@ChNCs consists of the ability to track their fate both intra and extracellularly. This journey is strictly dependent on the physico-chemical properties of the carrier and the cell types under investigation. Other applications make use of fluorescent ChNCs in cell labeling for the detection of disorders in vivo and controlling of living cells in situ. This review describes the use of FITC@ChNCs in the various applications with a focus on understanding their usefulness in labeled drug-delivery systems.

Chitosan-Based Non-viral Gene and Drug Delivery Systems for Brain Cancer

Central nervous system (CNS) tumors are a leading source of morbidity and mortality worldwide. Today, different strategies have been developed to allow targeted and controlled drug delivery into the brain. Gene therapy is a system based on the modification of patient's cells through the introduction of genetic material to exert a specific action. Administration of the foreign genetic material can be done through viral-mediated delivery or non-viral delivery via physical or mechanical systems. For brain cancer specifically, gene therapy can overcome the actual challenge of blood brain barrier penetration, the main reason for therapeutic failure. Chitosan (CS), a natural based biodegradable polymer obtained from the exoskeleton of crustaceans such as crab, shrimp, and lobster, has been used as a delivery vehicle in several non-viral modification strategies. This cationic polysaccharide is highly suitable for gene delivery mainly due to its chemical properties, its non-toxic nature, its capacity to protect nucleic acids through the formation of complexes with the genetic material, and its ease of degradation in organic environments. Recent evidence supports the use of CS as an alternative gene delivery system for cancer treatment. This review will describe multiple studies highlighting the advantages and challenges of CS-based delivery structures for the treatment of brain tumors. Furthermore, this review will provide insight on the translational potential of various CS based-strategies in current clinical cancer studies. Specifically, CS-based nanostructures including nanocapsules, nanospheres, solid-gel formulations, and nanoemulsions, also microshperes and micelles will be evaluated.

Overview of Dual-Acting Drug Methotrexate in Different Neurological Diseases, Autoimmune Pathologies and Cancers

Methotrexate, a structural analogue of folic acid, is one of the most effective and extensively used drugs for treating many kinds of cancer or severe and resistant forms of autoimmune diseases. In this paper, we take an overview of the present state of knowledge with regards to complex mechanisms of methotrexate action and its applications as immunosuppressive drug or chemotherapeutic agent in oncological combination therapy. In addition, the issue of the potential benefits of methotrexate in the development of neurological disorders in Alzheimer’s disease or myasthenia gravis will be discussed.

Comparison of Tanaka lipid mixture with natural surfactant Alveofact to study nanoparticle interactions on Langmuir film balance

Upon inhalation, nanoparticles enter the lungs where the pulmonary surfactant forms the first point of contact and plays a pivotal role for the subsequent absorption into the body. This can lead to interactions that alter the biophysical function of the surfactant monolayer. Therefore, a reliable prediction of the interaction is desired. In this study, we compared the behaviour of an artificial surfactant model with that of a natural surfactant upon exposure to chitosan nanoparticles. To simulate the physiology of the lungs, the surfactant monolayers were placed at an air/aqueous interface of a Langmuir film balance. Based on the data obtained from the experiments, the chitosan nanoparticles first integrated into the monolayer of the natural surfactant and then interact strongly with its compounds thereby moving out of the monolayer. The topographic changes in the monolayer were determined by atomic force microscopy analysis. Using this technique, the nanoparticle localisation on the monolayer could be studied. No visible interaction was observed with the artificial surfactant from surface pressure-time isotherms and atomic force microscopy analysis. Incomplete miscibility lead to instability of the artificial surfactant which left behind a DPPC rich monolayer after nanoparticle interaction. It was not stable enough to see a possible interaction (i.e. change in surface pressure) with the nanoparticles directly. These results should help understand the interactions of lipids among themselves and with the nanoparticles. Furthermore, it should help generate an efficient artificial surfactant model and to understand the underlying mechanisms of the nanoparticle interaction with the monolayer.

Formulation of acyclovir-loaded solid lipid nanoparticles: 2. Brain targeting and pharmacokinetic study

Acyclovir (ACV) is widely used in the treatment of herpes encephalitis. The present study was conducted to prepare chitosan-tween 80 coated solid lipid nanoparticles (SLNs) as a delivery system for brain targeting of ACV in rabbits. The SLNs were prepared and coated in one step by microemulsion method using a coating solution containing chitosan (0.1% w/v) and tween 80 (2% w/v) for loading sustained release ACV. In vitro characterization was performed for coated ACV-SLNs. Concerning in vivo experiments; a single intravenous bolus dose of coated ACV-SLNs was given versus free ACV solution to rabbits (62 mg/kg). Plasma pharmacokinetic parameters were calculated from the ACV concentration-time profiles in plasma using the two compartmental analysis. The values of AUC_0-∞ and MRT of coated ACV-SLNs were higher than free drug by about twofold, 233.36 ± 41.56 μg.h/mL and 1.81 ± 0.36 h, respectively. The noncompartmental analysis was conducted to estimate the brain pharmacokinetic parameters. The AUC_0-∞ brain/AUC_0-∞ plasma ratio for coated ACV-SLNs and free ACV was 0.22 and 0.12, respectively. These results indicated the effectiveness of using coated ACV-SLNs for brain targeting.

Synthesis of surface modified Fe3O4 super paramagnetic nanoparticles for ultra sound examination and magnetic resonance imaging for cancer treatment

In the present work, Fe₃O₄ nanoparticles with superparamagnetic properties were prepared and capped by using Chitosan. The synthesized NPs were studied by using transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. Average particle size and surface charge of the synthesized NPs were characterized by using Malvern Zetasizer instrument. TEM images showed the morphology and size distribution of uncoated Fe₃O₄ NPs, exhibiting the uniform sized NPS with an average particle size of about 10 nm. Vibrating Scanning Magnetometry (VSM) experiments, showed the superparamagnetic nature of the prepared nanoparticles. Fe₃O₄ NPs showed ferromagnetic magnetization which is very sensitive towards the sample's nanostructure. The results of paramagnetic studies exhibited the substantial reduction in paramagnetic behavior after Chitosan coating but sufficient for responding in magnetic field. Further, the in-vitro ability of the Chitosan coated Fe₃O₄ NPs as contrast agents in efficient Ultra sound/Magnetic resonance (US/MR) imaging was investigated. These findings demonstrated that the Chitosan coated super para magnetic iron oxide nanoparticles (SPION) have reported significant contrast-enhanced imaging potential for dual-mode US/MR imaging. Hence, the prepared Chitosan coated SPION composites administration serve as potential guide in the diagnosis and treatment of cancers.

Improved oral bioavailability of repaglinide, a typical BCS Class II drug, with a chitosan-coated nanoemulsion

The aim of the present study was to develop modified nanoemulsions to improve the oral bioavailability and pharmacokinetics of a poor water-soluble drug, repaglinide (RPG). The repaglinide-loaded nanoemulsions (RPG-NEs) were prepared from olive oil as internal phase, span 80, tween 80, and poloxamer 188 as emulsifiers, using homogenization technique. The mean droplet size, zeta potential, and entrapment efficiency of RPG-NEs were 86.5 ± 3.4 nm, -33.8 ± 2.1 mV, and 96.3 ± 2.3%, respectively. The chitosan-coated RPG-NEs (Cs-RPG-NEs) showed an average droplet size of 149.3 ± 3.9 nm and a positive zeta-potential of +31.5 ± 2.8 mV. Drug release profile of RPG-NEs was significantly higher than free drug in the simulated gastrointestinal fluids (p < .005). The in vivo study revealed 3.51- and 1.78-fold increase in the AUC_0-12h and C_max of the drug, respectively, in RPG-NEs-receiving animals in comparison to the free drug. The pharmacokinetic analysis confirmed that Cs-RPG-NEs were more efficient than uncoated ones for the oral delivery of RPG. Cs-RPG-NEs showed a longer t_1/2 and higher AUC_0-∞ compared to control group. The relative bioavailability of Cs-RPG-NEs was higher than that of uncoated RPG-NEs and free drug. Collectively, these findings suggest that chitosan-coated nanoemulsions are promising carrier for improving the oral bioavailability of RPG.

Chitosan-Based Nanocarriers for Nose to Brain Delivery

In the treatment of brain diseases, most potent drugs that have been developed exhibit poor therapeutic outcomes resulting from the inability of a therapeutic amount of the drug to reach the brain. These drugs do not exhibit targeted drug delivery mechanisms, resulting in a high concentration of the drugs in vital organs leading to drug toxicity. Chitosan (CS) is a natural-based polymer. It has unique properties such as good biodegradability, biocompatibility, mucoadhesive properties, and it has been approved for biomedical applications. It has been used to develop nanocarriers for brain targeting via intranasal administration. Nanocarriers such as nanoparticles, in situ gels, nanoemulsions, and liposomes have been developed. In vitro and in vivo studies revealed that these nanocarriers exhibited enhanced drug uptake to the brain with reduced side effects resulting from the prolonged contact time of the nanocarriers with the nasal mucosa, the surface charge of the nanocarriers, the nano size of the nanocarriers, and their capability to stretch the tight junctions within the nasal mucosa. The aforementioned unique properties make chitosan a potential material for the development of nanocarriers for targeted drug delivery to the brain. This review will focus on chitosan-based carriers for brain targeting.

Neuropharmacokinetic evaluation of lactoferrin-treated indinavir-loaded nanoemulsions: remarkable brain delivery enhancement

OBJECTIVE

Indinavir (IDV), an antiretroviral protease inhibitor used in treatment of HIV infection, has limited entry into brain due to efflux by the P-glycoprotein presented in blood-brain barrier. The aim of present study was to develop lactoferrin-treated nanoemulsion containing indinavir (Lf-IDV-NEs) for delivery to brain.

METHODS

Indinavir-loaded nanoemulsions (IDV-NEs) were prepared by high-speed homogenization method, and then lactoferrin was coupled to IDV-NEs by water soluble EDC method.

RESULTS

The hydrodynamic diameters, polydispersity index, and zeta potential of IDV-NEs were 112 ± 3.5 nm, 0.20 ± 0.02, and -33.2 ± 2.6 mV, respectively. From in vivo studies in animal model of rats, the AUC_0-4 h of brain concentration-time profile of IDV-NEs and Lf-IDV-NEs were 1.6 and 4.1 times higher than free drug, respectively. The brain uptake clearance of IDV-NEs and Lf-IDV-NEs were, interestingly, 393- and 420-times higher than the free drug.

CONCLUSIONS

It can be concluded that applying both lactoferrin-treated and non-treated nanoemulsions clearly leads to significant brain penetration enhancement of indinavir, an effect which is more pronounced in the case of Lf-IDV-NEs with the higher drug residence time in brain.

A mechanistic investigation on methotrexate-loaded chitosan-based hydrogel nanoparticles intended for CNS drug delivery: Trojan horse effect or not?

Chitosan-based hydrogel nanoparticles provide a higher brain concentration of methotrexate (MTX) following IV administration in comparison with the drug's simple solution. The present study investigates the mechanism of this phenomenon, focusing on the possible role of P-gp. A previously developed MTX containing chitosan nanogel was fabricated and characterised. Then 48 rats were divided into four groups: two receiving nanogels and two receiving solution of MTX, while 1 of each two had received a verapamil dose 30 min before MTX. Then, rats were sacrificed in four time points in triplicate, and MTX concentration in their plasma and brains were quantified and were compared statistically. Following IV injection, spherical nanogels with a mean diameter of <200 nm, zeta potential of 22.8 ± 6.55 mv, Loading efficiency of 72.03 ± 0.85, and loading capacity of 1.41 ± 0.02 produce a significantly higher brain concentration compared with the simple solution. Furthermore, those receiving verapamil presented a higher brain concentration. It seems that in the short term after drug administration (<1 h) nanogels facilitate MTX passage by providing a higher concentration of drug in contact with BBB, but in a more extended period nanogels pass the BBB and release their content beyond that.

Lipid and TPGS based novel core-shell type nanocapsular sustained release system of methotrexate for intravenous application

Core shell nanocapsules present an interesting system for attaining high loading of drug. In an attempt, lipid and TPGS based novel core-shell nanocapsule were prepared to achieve high drug loading with sustained release of model hydrophilic drug methotrexate (MTX). Antisolvent nanoprecipitation was utilized for the formulation of nanoparticles. Optimized formulation depicted 223.6 ± 24.1 nm particle size, 0.243 ± 0.034 PDI, zeta potential -2.07 ± 0.51 mV and 15.03 ± 1.92%drug loading. In vitro release showed biphasic release for 12 h with initial burst phase followed by sustained release phase. Haemolytic study on RBCs revealed haemocompatible nature of MTX-TPGS nanoparticles compared to Biotrexate^® (Zydus). In vitro cell culture studies depicted 3 folds and 2.66 folds increase in cellular uptake of MTX at 10 μg/ml and 15 μg/ml respectively for developed nanoparticles with 3.81 folds decrease in IC₅₀ value as compared to Biotrexate^®. Higher apoptosis and increased lysosomal membrane permeability were also depicted by MTX-TPGS nanoparticles. 2.45 folds increase in AUC and 3.68 folds increase in T_1/2 was achieved in pharmacokinetic study. Significant reduction in tumor burden and serum biochemical parameters depicted efficacy and safety respectively of the formulation as compared to Biotrexate^®. RBCs morphology was retained after MTX-TPGS exposure proving its haemocompatibility in vivo.

Effects of PEG surface density and chain length on the pharmacokinetics and biodistribution of methotrexate-loaded chitosan nanoparticles

Background

One of the most important aspects of drug delivery is extended nanoparticle (NP) residence time in vivo. Herein, we report a series of methotrexate (MTX)-loaded chito-san (CS) NPs coated with differently sized methoxy polyethylene glycol (mPEG) at different mPEG surface densities.

Materials and methods

MTX was incorporated into NPs (112.8–171.2 nm in diameter) prepared from the resulting mPEG-g-CS. The NPs had a zeta potential of +7.4–35.0 mV and MTX loading efficiency of 17.1%–18.4%. MTX/mPEG-g-CS NPs showed an initial burst release of MTX followed by a sustained-release profile in PBS at pH 7.4.

Results

The in vitro cellular uptake study showed that MTX accumulation in J774A.1 macrophage cells decreased with increasing the mPEG surface density or the mPEG molecular weight. The pharmacokinetic study on Sprague Dawley rats revealed an increase in AUC0–72 h (area under the plasma drug concentration–time curve over a period of 72 hours) with increasing the mPEG surface density or the mPEG molecular weight and a linear correlation between the mPEG surface density and AUC_{0–72 h}.

Conclusion

The biodistribution study on Institute of Cancer Research (ICR) mice revealed that MTX/mPEG-g-CS NPs significantly enhanced blood circulation time in the body and decreased accumulation in liver, spleen, and lung. These results suggest the potential of the mPEG-g-CS NPs as a promising candidate for drug delivery.

Targeting experimental orthotopic glioblastoma with chitosan-based superparamagnetic iron oxide nanoparticles (CS-DX-SPIONs)

Background

Glioblastoma is the most devastating primary brain tumor of the central nervous system in adults. Magnetic nanocarriers may help not only for a targeted delivery of chemotherapeutic agents into the tumor site but also provide contrast enhancing properties for diagnostics using magnetic resonance imaging (MRI).

Methods

Synthesized hybrid chitosan-dextran superparamagnetic nanoparticles (CS-DX-SPIONs) were characterized using transmission electron microscopy (TEM) and relaxometry studies. Nonlinear magnetic response measurements were employed for confirming the superparamagnetic state of particles. Following in vitro analysis of nanoparticles cellular uptake tumor targeting was assessed in the model of the orthotopic glioma in rodents.

Results

CS-DX-SPIONs nanoparticles showed a uniform diameter of 55 nm under TEM and superparamagentic characteristics as determined by T₁ (spin-lattice relaxation time) and T₂ (spin-spin relaxation time) proton relaxation times. Application of the chitosan increased the charge from +8.9 to +19.3 mV of the dextran-based SPIONs. The nonlinear magnetic response at second harmonic of CS-DX-SPIONs following the slow change of stationary magnetic fields with very low hysteresis evidenced superparamagnetic state of particles at ambient temperatures. Confocal microscopy and flow cytometry studies showed an enhanced internalization of the chitosan-based nanoparticles in U87, C6 glioma and HeLa cells as compared to dextran-coated particles. Cytotoxicity assay demonstrated acceptable toxicity profile of the synthesized nanoparticles up to a concentration of 10 μg/ml. Intravenously administered CS-DX-SPIONs in orthotopic C6 gliomas in rats accumulated in the tumor site as shown by high-resolution MRI (11.0 T). Retention of nanoparticles resulted in a significant contrast enhancement of the tumor image that was accompanied with a dramatic drop in T₂ values (P<0.001). Subsequent histological studies proved the accumulation of the nanoparticles inside glioblastoma cells.

Conclusion

Hybrid chitosan-dextran magnetic particles demonstrated high MR contrast enhancing properties for the delineation of the brain tumor. Due to a significant retention of the particles in the tumor an application of the CS-DX-SPIONs could not only improve the tumor imaging but also could allow a targeted delivery of chemotherapeutic agents.

Farnesylthiosalicylic acid-loaded lipid-polyethylene glycol-polymer hybrid nanoparticles for treatment of glioblastoma

OBJECTIVES

We aimed to develop lipid-polyethylene glycol (PEG)-polymer hybrid nanoparticles, which have high affinity to tumour tissue with active ingredient, a new generation antineoplastic drug, farnesylthiosalicylic acid (FTA) for treatment of glioblastoma.

METHOD

Farnesylthiosalicylic acid-loaded poly(lactic-co-glycolic acid)-1,2 distearoyl-glycerol-3-phospho-ethanolamine-N [methoxy (PEG)-2000] ammonium salt (PLGA-DSPE-PEG) with or without 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) hybrid nanoparticles has been prepared and evaluated for in-vitro characterization. Cytotoxicity of FTA-loaded nanoparticles along with its efficacy on rat glioma-2 (RG2) cells was also evaluated both in vitro (in comparison with non-malignant cell line, L929) and in vivo.

KEY FINDINGS

Scanning electron microscopy studies showed that all formulations prepared had smooth surface and spherical in shape. FTA and FTA-loaded nanoparticles have cytotoxic activity against RG2 glioma cell lines in cell culture studies, which further increases with addition of DOTAP. Magnetic resonance imaging and histopathologic evaluation on RG2 tumour cells in rat glioma model (49 female Wistar rats, 250-300 g) comparing intravenous and intratumoral injections of the drug have been performed and FTA-loaded nanoparticles reduced tumour size significantly in in-vivo studies, with higher efficiency of intratumoral administration than intravenous route.

CONCLUSION

Farnesylthiosalicylic acid-loaded PLGA-DSPE-PEG-DOTAP hybrid nanoparticles are proven to be effective against glioblastoma in both in-vitro and in-vivo experiments.

Effects of curcumin-loaded PLGA nanoparticles on the RG2 rat glioma model

BACKGROUND

Curcumin, the active ingredient of turmeric, has a remarkable antitumor activity against various cancers, including glioblastoma. However, it has poor absorption and low bioavailability; thus, to cross the blood-brain barrier and reach tumor tissue, it needs to be transferred to tumor site by special drug delivery systems, such as nanoparticles.

OBJECTIVE

We aimed to evaluate the antitumor activity of curcumin on glioblastoma tissue in the rat glioma-2 (RG2) tumor model when it is loaded on poly(lactic-co-glycolic acid)-1,2-distearoyl-glycerol-3-phospho-ethanolamine-N-[methoxy (polyethylene glycol)-2000] ammonium salt (PLGA-DSPE-PEG) hybrid nanoparticles.

METHODS

Glioblastoma was induced in 42 adult female Wistar rats (250-300g) by RG2 tumor model. The curcumin-loaded nanoparticles were injected by intravenous (n=6) or intratumoral route (n=6). There were five control groups, each containing six rats. First control group was not applied any treatment. The remaining four control groups were given empty nanoparticles or curcumin alone by intravenous or intratumoral route, respectively. The change in tumor volume was assessed by magnetic resonance imaging and histopathology before and 5days after drug injections.

RESULTS

Tumor size decreased significantly after 5days of intratumoral injection of curcumin-loaded nanoparticle (from 66.6±44.6 to 34.9±21.7mm³, p=0.028), whereas it significantly increased in nontreated control group (from 33.9±21.3 to 123.7±41.1mm³, p=0.036) and did not significantly change in other groups (p>0.05 for all).

CONCLUSION

In this in vivo experimental model, intratumoral administration of curcumin-loaded PLGA-DSPE-PEG hybrid nanoparticles was effective against glioblastoma. Curcumine-loaded nanoparticles may have potential application in chemotherapy of glioblastoma.

Strategies for transporting nanoparticles across the blood-brain barrier

The existence of blood-brain barrier (BBB) hampers the effective treatment of central nervous system (CNS) diseases. Almost all macromolecular drugs and more than 98% of small molecule drugs cannot pass the BBB. Therefore, the BBB remains a big challenge for delivery of therapeutics to the central nervous system. With the structural and mechanistic elucidation of the BBB under both physiological and pathological conditions, it is now possible to design delivery systems that could cross the BBB effectively. Because of their advantageous properties, nanoparticles have been widely deployed for brain-targeted delivery. This review paper presents the current understanding of the BBB under physiological and pathological conditions, and summarizes strategies and systems for BBB crossing with a focus on nanoparticle-based drug delivery systems. In summary, with wider applications and broader prospection the treatment of brain targeted therapy, nano-medicines have proved to be more potent, more specific and less toxic than traditional drug therapy.

Preparation, Characterization, and Optimization of Folic Acid-Chitosan-Methotrexate Core-Shell Nanoparticles by Box-Behnken Design for Tumor-Targeted Drug Delivery

The objective of this study was to investigate the combined influence of independent variables in the preparation of folic acid-chitosan-methotrexate nanoparticles (FA-Chi-MTX NPs). These NPs were designed and prepared for targeted drug delivery in tumor. The NPs of each batch were prepared by coaxial electrospray atomization method and evaluated for particle size (PS) and particle size distribution (PSD). The independent variables were selected to be concentration of FA-chitosan, ratio of shell solution flow rate to core solution flow rate, and applied voltage. The process design of experiments (DOE) was obtained with three factors in three levels by Design expert software. Box-Behnken design was used to select 15 batches of experiments randomly. The chemical structure of FA-chitosan was examined by FTIR. The NPs of each batch were collected separately, and morphologies of NPs were investigated by field emission scanning electron microscope (FE-SEM). The captured pictures of all batches were analyzed by ImageJ software. Mean PS and PSD were calculated for each batch. Polynomial equation was produced for each response. The FE-SEM results showed the mean diameter of the core-shell NPs was around 304 nm, and nearly 30% of the produced NPs are in the desirable range. Optimum formulations were selected. The validation of DOE optimization results showed errors around 2.5 and 2.3% for PS and PSD, respectively. Moreover, the feasibility of using prepared NPs to target tumor extracellular pH was shown, as drug release was greater in the pH of endosome (acidic medium). Finally, our results proved that FA-Chi-MTX NPs were active against the human epithelial cervical cancer (HeLa) cells.

Chitosan nanoparticles and their Tween 80 modified counterparts disrupt the developmental profile of zebrafish embryos

Chitosan nanoparticles (CS-NPs) and their Tween 80 modified counterparts (TmCS-NPs) are among the most commonly used brain-targeted vehicles. However, their potential developmental toxicity is poorly understood. In this study, zebrafish embryos are introduced as an in vivo platform. Both NPs showed a dose-dependent increase in developmental toxicity (decreased hatching rate, increased mortality and incidences of malformation). Neurobehavioral changes included decreased spontaneous movement in TmCS-NP treated embryos and hyperactive effect in CS-NP treated larvae. Both NPs remarkably inhibited axonal development of primary and secondary motor neurons, and affected the muscle structure. Overall, this study demonstrated that CS-NPs and TmCS-NPs could affect embryonic development, disrupt neurobehavior of zebrafish larvae and affect muscle and neuron development, suggesting more attention on biodegradable chitosan nanoparticles.

Nano-structures mediated co-delivery of therapeutic agents for glioblastoma treatment: A review

Glioblastoma is a malignant brain tumor and leads to death in most patients. Chemotherapy is a common method for brain cancer in clinics. However, the recent advancements in the chemotherapy of brain tumors have not been efficient enough. With the advancement of nanotechnology, the used drugs can enhance chemotherapy efficiency and increase the access to brain cancers. Combination of therapeutic agents has been recently attracted great attention for glioblastoma chemotherapy. One of the early benefits of combination therapies is the high potential to provide synergistic effects and decrease adverse side effects associated with high doses of single anticancer drugs. Therefore, brain tumor treatments with combination drugs can be considered as a crucial approach for avoiding tumor growth. This review investigates current progress in nano-mediated co-delivery of therapeutic agents with focus on glioblastoma chemotherapy prognosis.

In vitro screening of nanomedicines through the blood brain barrier: A critical review

The blood-brain barrier accounts for the high attrition rate of the treatments of most brain disorders, which therefore remain one of the greatest health-care challenges of the twenty first century. Against this background of hindrance to brain delivery, nanomedicine takes advantage of the assembly at the nanoscale of available biomaterials to provide a delivery platform with potential to raising brain levels of either imaging or therapeutic agents. Nevertheless, to prevent later failure due to ineffective drug levels at the target site, researchers have been endeavoring to develop a battery of in vitro screening procedures that can predict earlier in the drug discovery process the ability of these cutting-edge drug delivery platforms to cross the blood-brain barrier for biomedical purposes. This review provides an in-depth analysis of the currently available in vitro blood-brain barrier models (both cell-based and non-cell-based) with the focus on their suitability for understanding the biological brain distribution of forthcoming nanomedicines. The relationship between experimental factors and underlying physiological assumptions that would ultimately lead to a more predictive capacity of their in vivo performance, and those methods already assayed for the evaluation of the brain distribution of nanomedicines are comprehensively discussed.

Identifying lipidic emulsomes for improved oxcarbazepine brain targeting: In vitro and rat in vivo studies

Lipid-based nanovectors offer effective carriers for brain delivery by improving drug potency and reducing off-target effects. Emulsomes are nano-triglyceride (TG) carriers formed of lipid cores supported by at least one phospholipid (PC) sheath. Due to their surface active properties, PC forms bilayers at the aqueous interface, thereby enabling encapsulated drug to benefit from better bioavailability and stability. Emulsomes of oxcarbazepine (OX) were prepared, aimed to offer nanocarriers for nasal delivery for brain targeting. Different TG cores (Compritol(®), tripalmitin, tristearin and triolein) and soya phosphatidylcholine in different amounts and ratios were used for emulsomal preparation. Particles were modulated to generate nanocarriers with suitable size, charge, encapsulation efficiency and prolonged release. Cytotoxicity and pharmacokinetic studies were also implemented. Nano-spherical OX-emulsomes with maximal encapsulation of 96.75% were generated. Stability studies showed changes within 30.6% and 11.2% in the size and EE% after 3 months. MTT assay proved a decrease in drug toxicity by its encapsulation in emulsomes. Incorporation of OX into emulsomes resulted in stable nanoformulations. Tailoring emulsomes properties by modulating the surface charge and particle size produced a stable system for the lipophilic drug with a prolonged release profile and mean residence time and proved direct nose-to-brain transport in rats.

Inclusion of a pH-responsive amino acid-based amphiphile in methotrexate-loaded chitosan nanoparticles as a delivery strategy in cancer therapy

The encapsulation of antitumor drugs in nanosized systems with pH-sensitive behavior is a promising approach that may enhance the success of chemotherapy in many cancers. The nanocarrier dependence on pH might trigger an efficient delivery of the encapsulated drug both in the acidic extracellular environment of tumors and, especially, in the intracellular compartments through disruption of endosomal membrane. In this context, here we reported the preparation of chitosan-based nanoparticles encapsulating methotrexate as a model drug (MTX-CS-NPs), which comprises the incorporation of an amino acid-based amphiphile with pH-responsive properties (77KS) on the ionotropic complexation process. The presence of 77KS clearly gives a pH-sensitive behavior to NPs, which allowed accelerated release of MTX with decreasing pH as well as pH-dependent membrane-lytic activity. This latter performance demonstrates the potential of these NPs to facilitate cytosolic delivery of endocytosed materials. Outstandingly, the cytotoxicity of MTX-loaded CS-NPs was higher than free drug to MCF-7 tumor cells and, to a lesser extent, to HeLa cells. Based on the overall results, MTX-CS-NPs modified with the pH-sensitive surfactant 77KS could be potentially useful as a carrier system for intracellular drug delivery and, thus, a promising targeting anticancer chemotherapeutic agent.

Brain Localization and Neurotoxicity Evaluation of Polysorbate 80-Modified Chitosan Nanoparticles in Rats

The toxicity evaluation of inorganic nanoparticles has been reported by an increasing number of studies, but toxicity studies concerned with biodegradable nanoparticles, especially the neurotoxicity evaluation, are still limited. For example, the potential neurotoxicity of Polysorbate 80-modified chitosan nanoparticles (Tween 80-modified chitosan nanoparticles, TmCS-NPs), one of the most widely used brain targeting vehicles, remains unknown. In the present study, TmCS-NPs with a particle size of 240 nm were firstly prepared by ionic cross-linking of chitosan with tripolyphosphate. Then, these TmCS-NPs were demonstrated to be entered into the brain and specially deposited in the frontal cortex and cerebellum after systemic injection. Moreover, the concentration of TmCS-NPs in these two regions was found to decrease over time. Although no obvious changes were observed for oxidative stress in the in vivo rat model, the body weight was found to remarkably decreased in a dose-dependent manner after exposure to TmCS-NPs for seven days. Besides, apoptosis and necrosis of neurons, slight inflammatory response in the frontal cortex, and decrease of GFAP expression in the cerebellum were also detected in mouse injected with TmCS-NPs. This study is the first report on the sub-brain biodistribution and neurotoxicity studies of TmCS-NPs. Our results provide new insights into the toxicity evaluation of nanoparticles and our findings would help contribute to a better understanding of the neurotoxicity of biodegradable nanomaterials used in pharmaceutics.

Neuropharmacokinetic evaluation of methotrexate-loaded chitosan nanogels

Delivery of the hydrophilic drugs to the brain is still a great challenge for the treatment of many CNS-related diseases. Nanogels loaded by methotrexate (MTX) were prepared using the ionic gelation method. After intravenous administration of surface-modified (SMNs) and unmodified nanogels (UMNs) compared to the free drug, the neuropharmacokinetic evaluations were applied mainly by tissue drug uptake and graphic estimation of the uptake clearance methods. In optimized condition, the particle sizes of UMNs and SMNs were 118.54±15.93 nm and 106.68±7.23 nm, respectively. Drug entrapment efficiency and drug loading capacity were 61.82±6.84%, and 53.68±3.09%, respectively. The brain concentrations of MTX were shown to be higher in the case of both types of the nanogels. There were no significant differences between SMNs and UMNs in terms of the brain concentrations and AUCs of brain concentration-time profiles. Meanwhile, the brain uptake clearance of the drug loaded in SMNs were significantly higher than UMN ones (i.e. about 3- and 1.6-times for the high and low MTX doses, respectively). It can be concluded that, while the drug loading in both forms of nanogels have a significant increasing effect on the brain penetration of MTX, surface treatment of nanogels exerts an additional effect on the plasma volume cleared from MTX via brain tissue in time unit.

Self-assembled lysozyme/carboxymethylcellulose nanogels for delivery of methotrexate

Nanogels (NGs) were fabricated with lysozyme and carboxymethylcellulose via a green self-assembly method. The prepared NGs were characterized by dynamic light scattering (DLS), zeta potential, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Pyrene and isothiocyanate were introduced as fluorescent probes to research the hydrophobic area of the NGs and cells endocytosis, respectively. Methotrexate (MTX) was used to investigate the drug encapsulation property of the NGs. It turned out to be that the drug loaded NGs were regular spherical shape with a hydrodynamic diameter of about 123 nm. The drug loading efficiency was about 14.2%. The NGs can slowly release the drug and increase the bioavailability of the loaded drug. The NGs are promising carriers for the delivery of drugs and other bioactive molecules.

Recent advances in diagnosis and treatment of gliomas using chlorotoxin-based bioconjugates

Malignant gliomas, especially glioblastoma multiforme, are the most widely distributed and deadliest brain tumors because of their resistance to surgical and medical treatment. Research of glioma-specific bioconjugates for diagnosis and therapy developed rapidly during the past several years. Many studies have demonstrated that chlorotoxin (CTX) and Buthus martensii Karsch chlorotoxin (BmK CT) specifically inhibited glioma cells growth and metastasis, and accelerated tumor apoptosis. The bioconjugates of CTX or BmK CT with other molecules have played an increasing role in diagnostic imaging and treatment of gliomas. To date, CTX-based bioconjugates have achieved great success in phase I/II clinical trials about safety profiles. Here, we will provide a review on the important role of ion channels in the underlying mechanisms of gliomas invasive growth and how CTX suppresses gliomas proliferation and migration. We will summarize the recent advances in the applications of CTX bioconjugates for gliomas diagnosis and treatment. In addition, we will review recent studies on BmK CT bioconjugates and compare their efficacies with CTX derivatives. Finally, we will address advantages and challenges in the use of CTX or BmK CT bioconjugates as specific agents for theranostic applications in gliomas.

Drug delivery to the central nervous system by polymeric nanoparticles: what do we know?

Nanoparticles enable the delivery of a great variety of drugs including anticancer drugs, analgesics, anti-Alzheimer's drugs, cardiovascular drugs, protease inhibitors, and several macromolecules into the brain after intravenous injection of animals. The mechanism of the nanoparticle-mediated drug transport across the BBB appears to be receptor-mediated endocytosis followed by transcytosis into the brain or by drug release within the endothelial cells. Modification of the nanoparticle surface with covalently attached targeting ligands or by coating with certain surfactants that lead to the adsorption of specific plasma proteins after injection is necessary for this receptor-mediated uptake. A very critical and important requirement for nanoparticulate brain delivery is that the employed nanoparticles are biocompatible and, moreover, rapidly biodegradable, i.e. over a time frame of a few days. In addition to enabling drug delivery to the brain, nanoparticles, as with doxorubicin, may importantly reduce the drug's toxicity and adverse effects due to an alteration of the body distribution. Because of the possibility to treat severe CNS diseases such as brain tumours and to even transport proteins and other macromolecules across the blood-brain barrier, this technology holds great promise for a non-invasive therapy of these diseases.

Adjuvant chemotherapy for brain tumors delivered via a novel intra-cavity moldable polymer matrix

Introduction

Polymer-based delivery systems offer innovative intra-cavity administration of drugs, with the potential to better target micro-deposits of cancer cells in brain parenchyma beyond the resected cavity. Here we evaluate clinical utility, toxicity and sustained drug release capability of a novel formulation of poly(lactic-co-glycolic acid) (PLGA)/poly(ethylene glycol) (PEG) microparticles.

Methods

PLGA/PEG microparticle-based matrices were molded around an exvivo brain pseudo-resection cavity and analyzed using magnetic resonance imaging and computerized tomography. Invitro toxicity of the polymer was assessed using tumor and endothelial cells and drug release from trichostatin A-, etoposide- and methotrexate-loaded matrices was determined. To verify activity of released agents, tumor cells were seeded onto drug-loaded matrices and viability assessed.

Results

PLGA/PEG matrices can be molded around a pseudo-resection cavity wall with no polymer-related artifact on clinical scans. The polymer withstands fractionated radiotherapy, with no disruption of microparticle structure. No toxicity was evident when tumor or endothelial cells were grown on control matrices invitro. Trichostatin A, etoposide and methotrexate were released from the matrices over a 3-4 week period invitro and etoposide released over 3 days invivo, with released agents retaining cytotoxic capabilities. PLGA/PEG microparticle-based matrices molded around a resection cavity wall are distinguishable in clinical scanning modalities. Matrices are non-toxic invitro suggesting good biocompatibility invivo. Active trichostatin A, etoposide and methotrexate can be incorporated and released gradually from matrices, with radiotherapy unlikely to interfere with release.

Conclusion

The PLGA/PEG delivery system offers an innovative intra-cavity approach to administer chemotherapeutics for improved local control of malignant brain tumors.

A review of therapeutic challenges and achievements of methotrexate delivery systems for treatment of cancer and rheumatoid arthritis

PURPOSE

Methotrexate (MTX) is one of the most widely studied and effective therapeutics agents available to treat many solid tumors, hematologic malignancies, and autoimmune diseases such as rheumatoid arthritis; however, the poor pharmacokinetic and narrow safety margin of the drug limits the therapeutic outcomes of conventional drug delivery systems. For an improved delivery of MTX, several pathophysiological features such as angiogenesis, enhanced permeability and retention effects, acidosis, and expression of specific antigens and receptors can be used either as targets or as tools for drug delivery.

METHODS

There are many novel delivery systems developed to improve the pitfalls of MTX therapy ranged from polymeric conjugates such as human serum albumin, liposomes, microspheres, solid lipid nanoparticles, polymeric nanoparticles, dendrimers, polymeric micelles, in situ forming hydrogels, carrier erythrocyte, and nanotechnology-based vehicles such as carbon nanotubes, magnetic nanoparticles, and gold nanoparticles. Some are further modified with targeting ligands for active targeting purposes.

RESULTS

Such delivery systems provide prolonged plasma profile, enhanced and specific activity in vitro and in vivo in animal models. Nevertheless, more complementary studies are needed before they can be applied in human.

CONCLUSION

This review deals with the challenges of conventional systems and achievements of each pharmaceutical class of novel drug delivery vehicle.

Preparation and assessment of chitosan-coated superparamagnetic Fe3O4 nanoparticles for controlled delivery of methotrexate

In this study, Fe3O4 superparamagnetic nanoparticles were synthesized and stabilized by chitosan. Then the nanoparticles were characterized by Fourier transform infrared spectroscopy and transmission electron microscopy (TEM). Particle size distribution and Zeta potential of the particles also was assessed using Malvern Zetasizer. The paramagnetic behaviors of the uncoated and chitosan coated nanoparticles were measured using vibrating scanning magnetometry Particles morphology and size ranges of uncoated iron oxide nanoparticles were evaluated by TEM, showing uniform and narrow size distribution about 10 nm. After coating nanoparticles with chitosan and loading of methotrexate (MTX), the change in size was assessed using Zetasizer. Considerable increase in size was observed following the coating of the particles with chitosan and loading with MTX (the average size was 152 nm). Paramagnetic properties of the uncoated and chitosan-coated particles were assessed showing significant decrease in paramagnetic behavior after coating with chitosan, but it was enough to respond to the magnetic field. Finally loading efficiency, release rate and cytotoxicity of MTX were assessed indicating slow release behavior with the same levels of cell toxicity in SK-BR-3 cell lines, suggesting this formulation as a good candidate for the controlled delivery of MTX.

SYNTHESIS AND CHARACTERIZATION OF POLYSIALIC ACID-N-TRIMETHYL CHITOSAN NANOPARTICLES FOR DRUG DELIVERY

In drug delivery, the nanoparticles must be of proper size and charge to achieve high efficacy and low toxicity of associated therapeutics. In this study, nanoparticles were developed via ionic gelation of two polysaccharide-based molecules, negatively charged polysialic acid (PSA) and positively charged N,N,N-trimethylchitosan (TMC). PSA is unique in that the highly hydrated backbone may be used in a manner similar to that of poly(ethylene glycol) to extend circulation times. Although not necessary for nanoparticle formation, sodium tripolyphosphate (TPP) was added to enhance stability, as indicated by a reduced polydispersity. We investigated three different ratios by weight of PSA:TMC (0.5:1, 1:1, 1:2 and five different TPP concentrations ranging from 0.1 mg/ml to 0.8 mg/ml. As controls, nanoparticles were also formed without PSA from chitosan and TMC with TPP. Optimal size and surface charge were achieved with a PSA:TMC weight ratio of 0.5:1 and a TPP concentration 0.2 mg/ml. For the nanoparticles prepared in the latter fashion, a more in depth characterization was conducted. The nanoparticles were distinct solid, spherical nanogels with a size of 106 ± 25 nm, an ideal size to reduce uptake by the reticuloendothelial system while facilitating passive targeting of diseased tissue. The zeta potential of the nanoparticles was +33.9 ± 1.2 mV, suggesting that the nanoparticles will be stable under physiological conditions. Encapsulation and controlled release by the nanoparticles was demonstrated using methotrexate, a therapeutic indicated in both cancer and rheumatoid arthritis. The results obtained thus far strongly indicate that PSA–TMC nanoparticles are suitable drug carrier systems for systemic administration.