Chitosan-coated Nanoparticles Research Articles

Developmental toxicity of iron oxide nanoparticles with different coatings in zebrafish larvae

We report on the effect of different coatings (dextran, chitosan, polyethylene glycol, carboxy-silane, and silica) in the toxicity elicited by superparamagnetic iron oxide nanoparticles (SPIONs) in the developing zebrafish (Danio rerio). Animals were exposed to nanoparticle concentrations ranging from 0.125 to 8.0 mM of Fe during the first 5 days after fertilization. Embryotoxicity parameters (survival, hatching rate, and the incidence of anatomical malformations) and behavioral patterns (locomotion during the exploration of a new environment, thigmotaxis, and the escape response to an aversive stimulus) were evaluated. Exposed embryos hatched between 48 and 72 hpf, as expected for the species, but tendencies of either acceleration or delay were observed, depending on the nanoparticle coating. Malformations in exposed and control groups were similar, independent of the coating. Mortality rates were also not significantly affected by exposure to most of the coated SPIONs, except for animals treated with chitosan-coated nanoparticles, which induced 100% mortality at concentrations higher than 2 mM. A similar trend was observed in the behavioral parameters, in which significant adverse effects were mostly caused by chitosan-coated nanoparticles even at low concentrations. The higher toxicity observed for chitosan-coated particles raises concern and deserves further mechanistic investigations, considering the ample use of this compound in pharmaceutical and biomedical applications.

Experimental Study on Targeting Brain Tumor with Ultrasound Nanoparticles Across Blood Brain Barrier

Glioma is a malignant tumor that originates in the brain and accounts for more than half of all brain tumors. The disease is associated with a high fatality rate. Satisfactory treatment cannot be achieved through conventional craniotomy. We use carboxymethyl chitosan-coated Fe3 O4 composite nanoparticles (CMCS-Fe3 O4 NPs) as a drug delivery platform, and installed transferrin (TRF) with a targeting function on the platform. The anticancer drug methotrexate (MTX) is loaded onto the composite nanomaterial to complete a new delivery system for nano-drug targeted treatment of glioma. The composite nanoparticle is not toxic to cells in vitro, but after loading with it is loaded with MTX, it significantly inhibits proliferation of C6 cells. In vivo experiments show that CMCS-Fe3 O4NPs-TRF-MTX has a marked therapeutic effect on glioma in mouse models. The nano complex quickly penetrates the blood-brain barrier and enters brain tissues. An aggregation effect is not obvious. MRI monitoring for up to 4.0 h shows that CMCS-Fe3 O4 NPs-TRF-MTX slowly releases drug molecules over an extended period, thus increasing the duration of drug activity.

Lipopolysaccharide derived alginate coated Hepatitis B antigen loaded chitosan nanoparticles for oral mucosal immunization

Mucosal administration of vaccine can produce a strong immune response. Antigens adhere to “M-cells”, present at the intestinal mucosa and the M-cells produce immunity after actively transporting luminal antigens to the underlying immune cells. The objective of the present study was to prepare and characterize alginate coated chitosan nanoparticles (ACNPs) loaded with HBsAg as an antigen to produce immunity; additionally anchored with lipopolysaccharide (LPS) as an adjuvant. Ionic gelation method was used to prepare chitosan nanoparticles (CNPs) which were loaded with HBsAg and stabilized by alginate coating to protect from gastric environment. Results showed that the prepared LPS-HB-ACNPs were small and spherical with mean particle size 605.23 nm, polydispersity index 0.234 and Zeta potential −26.2 mV and could effectively protect antigen at GIT in acidic medium. HB-ANCPs were stable during storage at 4 ± 1 and 27 ± 2 °C. Anchoring with LPS showed increased immunity as compared to other formulations. Additionally, NPs elicited significant sIgA at mucosal secretions and IgG antibodies in systemic circulation. Thus, the prepared LPS anchored alginate coated chitosan NPs may be a promising approach as a vaccine delivery system for oral mucosal immunization.

Intranasally administered protein coated chitosan nanoparticles encapsulating influenza H9N2 HA2 and M2e mRNA molecules elicit protective immunity against avian influenza viruses in chickens

Chitosan nanoparticles (CNPs) represent an efficient vaccination tool to deliver immunogenic antigens to the antigen-presenting cells (APCs), which subsequently stimulate protective immune responses against infectious diseases. Herein, we prepared CNPs encapsulating mRNA molecules followed by surface coating with conserved H9N2 HA2 and M2e influenza proteins. We demonstrated that CNPs efficiently delivered mRNA molecules into APCs and had effectively penetrated the mucosal barrier to reach to the immune initiation sites. To investigate the potential of CNPs delivering influenza antigens to stimulate protective immunity, we intranasally vaccinated chickens with empty CNPs, CNPs delivering HA2 and M2e in both mRNA and protein formats (CNPs + RNA + Pr) or CNPs delivering antigens in protein format only (CNPs + Pr). Our results demonstrated that chickens vaccinated with CNPs + RNA + Pr elicited significantly (p < 0.05) higher systemic IgG, mucosal IgA antibody responses and cellular immune responses compared to the CNPs + Pr vaccinated group. Consequently, upon challenge with either H7N9 or H9N2 avian influenza viruses (AIVs), efficient protection, in the context of viral load and lung pathology, was observed in chickens vaccinated with CNPs + RNA + Pr than CNPs + Pr vaccinated group. In conclusion, we show that HA2 and M2e antigens elicited a broad spectrum of protection against AIVs and incorporation of mRNAs in vaccine formulation is an effective strategy to induce superior immune responses.

Synthesis, characterization and efficacy of antibiotic coated chitosan nanoparticles on human pathogens

The biodegradable nanoparticles of chitosan have received a significance attention as potential drug delivery vehicles in the recent decades. The present study was carried out to extract chitosan nanoparticles from shrimp shell waste and characterized followed by its potential antibacterial activity. Pure chitosan nanoparticles (CNP) and tetracycline coated nanoparticles (TCNP) were prepared by the ionotropic gelation process. The prepared nanoparticles were characterised by UV visible spectrophotometer, SEM, XRD, FTIR, NMR, Nano size - Zeta potential analysis. Antibacterial activity was assessed using CNP and TCNP against 7 different strains of human pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, Vibrio parahaemolyticus, Salmonella typhi, S. paratyphi, Pseudomonas aeruginosa and Bacillus subtilis. In the present study, the CNP and TCNP had exhibited a growth inhibition activity on bacteria at lower concentration and proved as a remarkable drug carrier.

Chitosan-Coated Mesoporous Silica Nanoparticle Treatment of Citrullus lanatus (Watermelon): Enhanced Fungal Disease Suppression and Modulated Expression of Stress-Related Genes

This work assesses the potential of mesoporous silica nanoparticles with or without a chitosan coating to suppress Fusarium wilt (Fusarium oxysporum f. sp. niveum) in watermelon (Citrullus lanatus)...

Cytotoxicity of hyaluronic acid coated chitosan nanoparticles containing nitric oxide donor against cancer cell lines

The incidence and mortality rates of all types of cancer have a global burden. The lack of specificity of chemotherapy is one of the major problems in cancer treatment and it is related with moderate to severe adverse effects. CD44 is a protein overexpressed in certain types of cancer cells and can be used as an anchor of attachment for nanoparticles decorated with hyaluronic acid (HA). HA is a natural polymer with high affinity for CD44 receptors. In this work, chitosan nanoparticles (CS NPs) were coated with HA to delivery nitric oxide (NO) donor to cancer cells. NO is a small molecule involved in several physiological processes and it has cytotoxicity against cancer cells. HA-coated and uncoated NO-releasing CS NPs were synthesized and characterized by different techniques. Uncoated and HA-coated NO-releasing CS NPs have hydrodynamic diameters of 142.80 ± 2.22 nm and 170.80 ± 0.14 nm, respectively, polydispersity index of 0.282 ± 0.010 and 0.37 ± 0.04, respectively, and a zeta potential values of + 25.20 ± 0.85 mV and + 15.60 ± 0.15 mV, respectively. As expected, the presence of HA layer on the surface of NO-releasing CS NPs increased hydrodynamic size ca. 20%. The encapsulation efficiency of the NO donor into CS NPs was found to be higher than 90%. The kinetic of NO release from uncoated and HA-coated CS NPs has two distinct phases, an initial burst followed by the establishment of a plateau, with a maximum of NO released at 40 mmol·L−1. At this concentration, NO is expected to have cytotoxic effects. The cytotoxicity of uncoated and HA-coated NO releasing CS NPs showed a concentration-dependent toxicity against human prostatic carcinoma (PC-3) and human uterine cervix carcinoma (HeLa) cell lines. Taken all together, uncoated and HA-coated NO-releasing CS NPs might find important biomedical applications, including cancer in treatment.

&lt;p&gt;In vitro–in vivo evaluation of chitosan-PLGA nanoparticles for potentiated gastric retention and anti-ulcer activity of diosmin&lt;/p&gt;

BackgroundDiosmin showed poor water solubility and low bioavailability. Poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles were successfully used to improve the drugs solubility and bioavailability. Coating of PLGA nanoparticles with chitosan can ameliorate their gastric retention and cellular uptake.MethodologyPLGA nanoparticles of diosmin were prepared using different drug and polymer amounts. Nanoparticles were selected based on entrapment efficiency% (EE%) and particle size measurements to be coated with chitosan. The selected nanoparticles either uncoated or coated were evaluated regarding morphology, ζ-potential, solid-state characterization, in vitro release, storage stability, and mucoadhesion. The anti-ulcer activity (AA) against ethanol-induced ulcer in rats was assessed through macroscopical evaluation, histopathological examination, immunohistochemical localization of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and transmission electron microscopic examination of gastric tissues compared to free diosmin (100 mg/kg) and positive control.ResultsBased on EE% and particle size measurements, the selected nanoparticles, either uncoated or coated with 0.1% w/v chitosan, were based on 1:15 drug-PLGA weight ratio and 20 mg diosmin employing methylene chloride as an organic phase. Examination by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed nanoscopic spherical particles. Drug encapsulation within the selected nanoparticles was suggested by Fourier transform-infrared, differential scanning calorimetry (DSC) and X-ray diffractometry results. Chitosan-coated nanoparticles were more stable against size enlargement probably due to the higher ζ-potential. Only coated nanoparticles showed gastric retention as revealed by SEM examination of stomach and duodenum. The superior AA of coated nanoparticles was confirmed by significant reduction in average mucosal damage, the majority of histopathological changes and NF-κB expression in gastric tissue when compared to positive control, diosmin and uncoated nanoparticles as well as insignificant difference relative to normal control. Coated nanoparticles preserved the normal ultrastructure of the gastric mucosa as revealed by TEM examination.ConclusionThe optimized chitosan-coated PLGA nanoparticles can be represented as a potential oral drug delivery system of diosmin.

Fabrication of Fe3O4 nanoparticles coated by extracted shrimp peels chitosan as sustainable adsorbents for removal of chromium contaminates from wastewater: The design of experiment

Water is the most critical substance on Earth; any contamination of water may cause harmful consequences for the entire living creatures. Today, removal of various pollutants from the water is one of the most critical concerns; in this regard, application of the minimum amount of chemicals or use of the natural structures and bio-synthetic methods for pollutant elimination are of critical importance. In this paper, Fe3O4 nanoparticles were biosynthesized by co-precipitation method at the presence of the shrimp-extracted chitosan and tripolyphosphate. The pure and chitosan-coated nanoparticles were characterized by scanning electron microscope SEM, TEM, EDX, FTIR, XRD, XPS, VSM and TGA methods. The application of the chitosan-coated Fe3O4 nanoparticles was then evaluated in the extraction and green removal of chromium (VI) from water samples. The effective parameters such as pH, contact time, adsorbent dosage, and agitation speed were optimized by design of experiment method and investigated by response surface methodology (RSM). Based on the results, 75–88% of Cr(VI) could be removed from the actual samples indicating the high chromate removal efficiency of the synthetic adsorbents.

Cell-free synthesis of connexin 43-integrated exosome-mimetic nanoparticles for siRNA delivery

Exosomes are naturally secreted nanovesicles that have emerged as a promising therapeutic nanodelivery platform, due to their specific composition and biological properties. However, challenges like considerable complexity, low isolation yield, drug payload, and potential safety concerns substantially reduce their pharmaceutical acceptability. Given that the nano-bio-interface is a crucial factor for nanocarrier behavior and function, modification of synthetic nanoparticles with the intrinsic hallmarks of exosomes’ membrane to create exosome mimetics could allow for siRNA delivery in a safer and more efficient manner. Herein, connexin 43 (Cx43)-embedded, exosome-mimicking lipid bilayers coated chitosan nanoparticles (Cx43/L/CS NPs) were constructed by using cell-free (CF) synthesis systems with plasmids encoding Cx43 in the presence of lipid-coated CS NPs (L/CS NPs). The integration of de novo synthesized Cx43 into the lipid bilayers of L/CS NPs occurred cotranslationally during one-pot reaction and, more importantly, the integrated Cx43 was functionally active in transport. In addition to considerably lower cytotoxicity (<four-fold) than cationic Lipo 2000, the obtained Cx43/L/CS-siRNA NPs showed feasible cellular uptake and silencing efficacy that was significantly higher than free siRNA and CS-siRNA NPs. By using a gap junction (GJ) inhibitor, 18β-glycyrrhetinic acid, we demonstrated that Cx43 facilitated the delivery of siRNA into Cx43-expressing U87 MG cells. Additionally, the cellular entry of Cx43/L/CS-siRNA NPs may rely on different endocytic mechanisms, depending on the types of recipient cells. However, Cx43/L/CS-siRNA NPs still exhibited far from adequate delivery efficiency compared with transfection reagent Lipo 2000. Taken together, our study provides a brand new strategy to construct Cx43-functionalized, exosome-mimetic nanoparticles, which may further encourage the establishment of more biomimetic nanocarriers with higher biocompatibility and delivery efficiency. Significance of statementThe major issue to move RNA interference (RNAi) therapy from bench to bedside is the lack of safe and efficient delivery vehicles. Given the certain advantages and limitations of exosomes and synthetic nanocarriers, a promising strategy is to facilitate positive feedbacks between the two fields, in which the superiority of exosomes regarding special membrane composition beneficial for cytoplasmic delivery and the better pharmaceutical acceptance of synthetic nanocarriers could be combined. In this study, we reported to construct Cx43-integrated, exosome-mimetic lipid bilayers coated nanoparticles by using CF synthesis technique. The obtained Cx43/L/CS-siRNA NPs were characterized by desirable cytotoxicity profile and feasible delivery efficiency. This study provides a new avenue and insights for the synthesis of more biocompatible and effective bio-mimetic siRNA delivery platforms.

Effect of Geometrical Structure, Drying, and Synthetic Method on Aminated Chitosan-Coated Magnetic Nanoparticles Utility for HSA Effective Immobilization.

Human serum albumin (HSA) is one of the most frequently immobilized proteins on the surface of carriers, including magnetic nanoparticles. This is because the drug–HSA interaction study is one of the basic pharmacokinetic parameters determined for drugs. In spite of many works describing the immobilization of HSA and the binding of active substances, research describing the influence of the used support on the effectiveness of immobilization is missing. There are also no reports about the effect of the support drying method on the effectiveness of protein immobilization. This paper examines the effect of both the method of functionalizing the polymer coating covering magnetic nanoparticles (MNPs), and the drying methods for the immobilization of HSA. Albumin was immobilized on three types of aminated chitosan-coated nanoparticles with a different content of amino groups long distanced from the surface Fe3O4-CS-Et(NH2)1–3. The obtained results showed that both the synthesis method and the method of drying nanoparticles have a large impact on the effectiveness of immobilization. Due to the fact that the results obtained for Fe3O4-CS-Et(NH2)2 significantly differ from those obtained for the others, the influence of the geometry of the shell structure on the ability to bind HSA was also explained by molecular dynamics.

Validation of an HPLC–UV Method for Quantifying Oncocalyxone A in Different Media and Nanocapsules

Oncocalyxone A (onco A) isolated from heartwood of Cordia oncocalyx (Auxemma oncocalyx), exhibits antitumor, analgesic and anti-inflammatory activities. In order to produce drug delivery systems containing onco A, the objective of this study was to develop and validate an HPLC method for quantifying onco A in different media and nanocapsules. The validation method was performed according to ICH guidelines for pharmaceutical products. The solubility of onco A was determined in deionized water, simulated gastric and intestinal fluids, buffer solutions at pH 5.5, 7.0, 9.0 and oils: copaiba, soybean and medium-chain triglycerides. The partition coefficients of onco A between n-octanol, oils and aqueous phase were determined at 25 °C. Accuracy, intra- and inter-day precision values presented low random errors (less than or equal to 2.53, 2.21 and 3.12%, respectively). Onco A solubility was greater in water, buffer solutions, and simulated gastric and intestinal fluids (817 ± 54 μg mL−1) than in oils (434 ± 25 μg mL−1). Onco A showed hydrophilic characteristics (log P < 1). The onco A content in chitosan-coated nanoparticles was 99.6% (995.8 ± 26.5 μg mL−1). In conclusion, a robust HPLC method for quantifying onco A was successfully developed, validated and applied for determining onco A solubility in different pHs, partition coefficient and nanocapsules.

Application of temporary agglomeration of chitosan-coated nanoparticles for the treatment of lung metastasis of melanoma

Temporary association of chitosan (CS)-coated nanoparticles (NPs) including phloretin (Phl) in the blood stream can be applied to treat lung metastasis of melanoma. Phl was entrapped in poly(d,l-lactide-co-glycolide) (PLGA) NPs as an anticancer agent, whereas CS was decorated onto the outer surfaces of the Phl-loaded PLGA NPs (PLGA/Phl NPs). CS-coated PLGA/Phl NPs (CS–PLGA/Phl NPs) with mean hydrodynamic sizes of 342 nm, spherical shapes, unimodal size distribution, positive zeta potentials, and drug encapsulation efficiency larger than 90% were prepared. The presence of the CS layers in the outer surfaces of the CS–PLGA/Phl NPs was elucidated by X-ray photoelectron spectroscopy. Upon blending of the CS–PLGA/Phl NPs with serum albumin, microscale agglomerates formed and easily dissociated into individual NPs by applying external forces. A sustained Phl release from NPs and similar antiproliferation potential of the CS–PLGA/Phl NPs to that of Phl in melanoma (B16F10) cells were observed. After multiple dosing of developed NPs in mouse models with lung metastasis of melanoma, the CS–PLGA/Phl NPs group exhibited significantly lower lung weight and number of metastasis foci than the PLGA/Phl NPs group (p < 0.05). These results suggest that the transient transformation of NPs into microscale aggregates and their facile dissociation into individual NPs can be efficiently and safely applied for the treatment of lung metastasis of melanoma.

Chitosan-Coated Nanoparticles: Effect of Chitosan Molecular Weight on Nasal Transmucosal Delivery.

Drug delivery to the brain represents a challenge, especially in the therapy of central nervous system malignancies. Simvastatin (SVT), as with other statins, has shown potential anticancer properties that are difficult to exploit in the central nervous system (CNS). In the present work the physico–chemical, mucoadhesive, and permeability-enhancing properties of simvastatin-loaded poly-ε-caprolactone nanocapsules coated with chitosan for nose-to-brain administration were investigated. Lipid-core nanocapsules coated with chitosan (LNCchit) of different molecular weight (MW) were prepared by a novel one-pot technique, and characterized for particle size, surface charge, particle number density, morphology, drug encapsulation efficiency, interaction between surface nanocapsules with mucin, drug release, and permeability across two nasal mucosa models. Results show that all formulations presented adequate particle sizes (below 220 nm), positive surface charge, narrow droplet size distribution (PDI < 0.2), and high encapsulation efficiency. Nanocapsules presented controlled drug release and mucoadhesive properties that are dependent on the MW of the coating chitosan. The results of permeation across the RPMI 2650 human nasal cell line evidenced that LNCchit increased the permeation of SVT. In particular, the amount of SVT that permeated after 4 hr for nanocapsules coated with low-MW chitosan, high-MW chitosan, and control SVT was 13.9 ± 0.8 μg, 9.2 ± 1.2 µg, and 1.4 ± 0.2 µg, respectively. These results were confirmed by SVT ex vivo permeation across rabbit nasal mucosa. This study highlighted the suitability of LNCchit as a promising strategy for the administration of simvastatin for a nose-to-brain approach for the therapy of brain tumors.

Self-assembly pH-sensitive chitosan/alginate coated polyelectrolyte complexes for oral delivery of insulin

Polyelectrolyte complexes (PEC) provide new opportunities for controlled release system of drugs, and have potentials to address challenges on the way to effective oral insulin delivery. Here, an innovative pH-sensitive PEC for insulin oral administration was developed, which was formed by self-assembly of two oppositely charged nanoparticles (chitosan-coated nanoparticles and alginate-coated nanoparticles) through electrostatic interaction via optimised double emulsion method. The encapsulation efficiency of insulin-loaded alginate-coated and chitosan-coated nanoparticles were 81.5 ± 7.4% and 55.2 ± 7.0%, respectively, and the particle size of these nanoparticles were in 200–300 nm range. The pH-dependent morphology of PEC was observed by transmission electron microscopy. The PEC exhibited insulin release profile triggered by pH in vitro and was non-cytotoxicity against Caco-2 cell. The insulin-loaded PEC could decrease blood glucose levels effectively and prolong insulin release after oral administration to diabetic rats. The results illustrated that the as-prepared PEC may be employed as a potential oral insulin delivery system.

Synthesis and characterization of chitosan-coated magnetite nanoparticles using a modified wet method for drug delivery applications

Immobilizing various chemical functionalities on the surfaces of magnetite nanoparticles extends these applications without affecting the overall magnetic properties of the coated nanoparticles. In this study, magnetite nanoparticles have been prepared in the presence of chitosan using a simple modified wet method. Composition, morphology and magnetic properties of the chitosan-coated nanoparticles were investigated. Results showed the formation of coating with various thicknesses on the surfaces of the superparamagnetic nanoparticles. This in turn reduced the magnetization of the nanoparticles to some extent. The least particle size obtained in the presence of chitosan was 10 nm.

Development and in vitro characterization of chitosan-coated polymeric nanoparticles for oral delivery and sustained release of the immunosuppressant drug mycophenolate mofetil

Objective: To develop an oral sustained release formulation of mycophenolate mofetil (MMF) for once-daily dosing, using chitosan-coated polylactic acid (PLA) or poly(lactic-co-glycolic) acid (PLGA) nanoparticles. The role of polymer molecular weight (MW) and drug to polymer ratio in encapsulation efficiency (EE) and release from the nanoparticles was explored in vitro.Methods: Nanoparticles were prepared by a single emulsion solvent evaporation method where MMF was encapsulated with PLGA or PLA at various polymer MW and drug: polymer ratios. Subsequently, chitosan was added to create coated cationic particles, also at several chitosan MW grades and drug: polymer ratios. All the formulations were evaluated for mean diameter and polydispersity, EE as well as in vitro drug release. Differential scanning calorimetry (DSC), surface morphology, and in vitro mucin binding of the nanoparticles were performed for further characterization.Results: Two lead formulations comprise MMF: high MW, PLA: medium MW chitosan 1:7:7 (w/w/w), and MMF: high MW, PLGA: high MW chitosan 1:7:7 (w/w/w), which had high EE (94.34% and 75.44%, respectively) and sustained drug release over 12 h with a minimal burst phase. DSC experiments revealed an amorphous form of MMF in the nanoparticle formulations. The surface morphology of the MMF NP showed spherical nanoparticles with minimal visible porosity. The potential for mucoadhesiveness was assessed by changes in zeta potential after incubation of the nanoparticles in mucin.Conclusion: Two chitosan-coated nanoparticles formulations of MMF had high EE and a desirable sustained drug release profile in the effort to design a once-daily dosage form for MMF.

Internalization capabilities of gold-198 nanoparticles: Comparative evaluation of effects of chitosan agent on cellular uptake into MCF-7

In this study, internalization of positively charged chitosan-coated nanoparticles (198AuNPs@chitosan) on MCF-7 cells was investigated by γ-ray spectroscopy and then statistically compared to that of 198Au and negatively charged citrate-stabilized nanoparticles (198AuNPs). Sub-50 nm 198AuNPs@chitosan had a higher internalization compared to 198Au and 198AuNPs (p < 0.05). More cellular uptake of 198AuNP@chitosan means a higher dose of radioactivity to the tumor cells which, in turn, more effective treatment of the cancer.

Polysorbate 80 coated crosslinked chitosan nanoparticles of ropinirole hydrochloride for brain targeting

Targeting ropinirole hydrochloride (R-HCl) to brain in effective amount may be a breakthrough in the treatment of Parkinson's disease due to its extensive first-pass metabolism in stomach after oral administration. The aim of the present investigation was to increase the brain uptake of R-HCl through chitosan nanoparticles prepared by conventional emulsification crosslinking method. The drug encapsulation efficiency (%), particle size, polydispersity index and zeta potential of polysorbate 80 coated R-HCl loaded chitosan nanoparticles were found satisfactory. These coated nanoparticles were characterized by SEM, FTIR and DSC analyses. In vitro drug release from different uncoated and coated chitosan nanoparticles showed initial burst release of R-HCl followed by a sustained release over 10 h. The coated nanoparticles were found stable over 3 months storage. In vivo biodistribution studies in Wistar rats exhibited higher R-HCl concentrations in brain with less accumulations of R-HCl in liver, spleen and kidney for polysorbate 80 coated R-HCl loaded chitosan nanoparticles after 1 h of dose administration (i.v.) as compared to these of uncoated R-HCl loaded chitosan nanoparticles and pure R-HCl. These observations suggested that the surface coated R-HCl loaded chitosan nanoparticles could be a useful tool to improve brain accumulation of R-HCl.

Surface-dependent endocytosis of poly(isobutylcyanoacrylate) nanoparticles by Trichomonas vaginalis

Previous data from our research group showed that chitosan-coated poly(isobutylcyanoacrylate) nanoparticles (NPs) (denoted PIBCA/Chito20) exhibited intrinsic anti-Trichomonas vaginalis activity, while PIBCA/pluronic® F68 without chitosan (PIBCA/F68) were inactive. However, the mechanism of anti-T. vaginalis activity of chitosan-coated PIBCA NPs is still unknown. Our hypothesis is that chitosan-coated NPs are internalized by the parasite, contrarily to PIBCA/F68. In this investigation, the impact of NP surface on their internalization by the protozoan was studied using flow cytometry and parasite morphological changes after different incubation times with PIBCA/Chito20 NPs were monitored by electron microscopy. Flow-cytometry revealed that PIBCA/Chito20 NPs were uptaken by T. vaginalis as early as 10-min-incubation. Drastic cell morphological transformations were observed from scanning electron microscopy and transmission electron microscopy after incubation with PIBCA/Chito20 NPs. Numerous pits were seen on cell membrane since 10 min. Gradual increase in contact time increased NP endocytosis and induced proportional damages to T. vaginalis membrane. Then, investigation of whether PIBCA/Chito20 NPs can improve MTZ anti-T. vaginalis activity was studied using checkerboard experiment. Calculation of fractional inhibitory concentration index (FICI = 3.53) showed an additive effect between NPs and MTZ.