Erythromycin encapsulation in nanoemulsion-based delivery systems for treatment of Helicobacter pylori infection: Protection and synergy.

Poorly water-soluble and unstable compounds are difficult to develop as drug products using conventional formulation techniques. The aim of the present study was to develop and evaluate a nanoformulation prepared by a hot high-pressure homogenization method, which was a scalable and solvent-free process. We successfully prepared stable nanodispersions to protect a labile antibiotic, erythromycin. The mean diameter of the dispersed droplets was approximately 150 nm, and size distribution was unimodal. Dispersion was physically stable at room temperature for over six months. Using erythromycin as a model compound, we studied its antimicrobial activity in vitro on Helicobacter pylori. Results showed that drug encapsulation improves API stability in an acidic environment and is conducive to a synergistic effect between the drug and the formulation.

The unexpected increase of clotrimazole apparent solubility using randomly methylated ß-cyclodextrin.

Clotrimazole (CTZ) and cyclodextrin (CD) inclusion complexes having improved apparent water solubility were obtained from phase solubility diagrams. ß-CD (1.5% w/w) and hydroxypropyl-ß-CD (40% w/w) offered poor CTZ solubility enhancements (12 and 384 times, respectively). Unexpectedly, the apparent solubility of CTZ was 9980 times increased from 0.4 µg.mL(-1) (1.42 µM) without CD to 4.89 mg.mL(-1) (14.9 mM) using randomly-methylated ß-CD (Me-ß-CD) (40% w/w). This is the highest apparent CTZ solubility improvement ever reported in the literature using conventional CDs. Quantitative nuclear magnetic resonance ((1) H-NMR) coupled with two-dimensional nuclear Overhauser effect (NOESY) experiments and molecular docking calculations showed that the highest interactions with Me-ß-CD were reported for CTZ two phenyl groups. A lower interaction was reported for chlorophenyl, while imidazole had the weakest interaction with Me-ß-CD.

Formulation and pharmacokinetics of thermosensitive stealth® liposomes encapsulating 5-Fluorouracil.

PURPOSE: We optimize the encapsulation and investigate the pharmacokinetics of 5-Fluorouracil (5-FU) delivered by thermosensitive stealth(®) liposomes (TSLs) designed to trigger drug release upon hyperthermia using focused ultrasound (FUS). METHODS: 5-FU was encapsulated into liposomes made of 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine/cholesterol/1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-PEG2000 either as a free molecule or complexed with copper-polyethylenimine. Heat-triggered drug release was evaluated using either a water bath or FUS. Formulation cytotoxicity was assessed on HT-29 cell line by MTS assay. Pharmacokinetics and biodistribution of 5-FU were evaluated in HT-29-tumor bearing mice. RESULTS: 5-FU was easily encapsulated using the lipid hydration method (encapsulation efficacy of 13%) but poorly retained upon dilution. 5-FU complexation with copper-polyethylenimine improved 5-FU retention into liposomes and allowed to obtain an encapsulation efficacy of 37%. At 42°C, heat-triggered 5-FU release from TSLs was 63% using a water bath and 68% using FUS, within 10 min, whereas it remained below 20% for the non-thermosensitive formulation. The MTS assay revealed that formulation toxicity arose from 5-FU and not from the excipients. In addition, 5-FU complex encapsulation into TSLs induces a reduction of the IC50 from 115 down to 49 µM. Pharmacokinetics reveals a longer circulation of encapsulated 5-FU and a more important body exposure, although tumor passive targeting is not significantly higher than free 5-FU. CONCLUSIONS: Complexation of 5-FU with copper-polyethylenimine appears an interesting strategy to improve 5-FU retention into TSLs in vitro and in vivo. TSLs allow heat-triggered release of the drug within 10 min at 42°C, a reasonable time for future in vivo experiments.

Novel isoprenoyl nanoassembled prodrug for paclitaxel delivery.

A new paclitaxel (Ptx) prodrug was designed by coupling a single terpene unit (MIP) to the hydroxyl group in position 2' of the drug molecule. Using a squalene derivative of polyethylene glycol (SQ-PEG) as surface active agent, the resulting bioconjugate (PtxMIP) self-assembled in water leading to the formation of stable nanoparticles (PtxMIP_SQ-PEG NPs) with an impressively high drug loading (82%). In vivo, the anticancer activity of this novel Ptx nanoassembled prodrug was compared to the conventional Cremophor-containing formulation (Taxol) on a murine model of breast cancer lung metastasis induced by intravenous injection of 4T1 tumor cells, genetically modified to stably express firefly luciferase. Cell growth was assessed noninvasively by bioluminescence imaging (BLI) which enabled monitoring tumor metastatic burden in the same animals. PtxMIP_SQ-PEG nanoparticles slowed metastatic spread and were better tolerated than the Cremophor-containing formulation (i.e., free drug), thus demonstrating the potential of terpene-based nanoassembled prodrugs in the improvement of the therapeutic index of Ptx in balb/c mice.

Pickering emulsions stabilized with biodegradable nanoparticles for the co-encapsulation of two active pharmaceutical ingredients.

Innovative Pickering emulsions co-encapsulating two active pharmaceutical ingredients (API) were formulated for a topical use. An immunosuppressive agent, either cyclosporine A (CysA) or tacrolimus (TAC), was encapsulated at high drug loading in biodegradable and biocompatible poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NP). These NP stabilized the oil droplets (Miglyol) containing an anti-inflammatory drug, calcitriol (CAL). The influence of the API on the physico-chemical properties of these emulsions were studied. Emulsions formulated with or without API had a similar macroscopic and microscopic structure, as well as interfacial properties, and they exhibited a good stability for at least 55 days. The emulsions did not alter the viability of human keratinocytes (HaCaT cell line) after 2 and 5 days of exposure to NP concentrations equivalent to efficient API dosages. Thus, these new Pickering emulsions appear as a promising multidrug delivery system for the treatment of chronical inflammatory skin diseases.

Tiny dexamethasone palmitate nanoparticles for intravitreal injection: Optimization and in vivo evaluation.

Tiny nanoparticles of dexamethasone palmitate (DXP) were designed as transparent suspensions for intravitreal administration to treat age-related macular degeneration (AMD). The influence of three surfactants (PEG-40-stearate and Pluronic block copolymers F68 and F127) on nanoparticles size and stability was investigated and led to an optimal formulation based on Pluronic F127 stabilizing DXP nanoparticles. Size measurements and TEM revealed tiny nanoparticles (around 35 nm) with a low opacity, compatible with further intravitreal injection. X-Ray powder diffraction (XRPD) and transmission electronic microscopy (TEM) performed on freeze-dried samples showed that DXP nanoparticles were rather monodisperse and amorphous. The efficacy of DXP nanoparticles was assessed in vivo on pigmented rabbits with unilateral intravitreal injections. After breakdown of the blood-retinal barrier (BRB) induced by injection of rhVEGF165 with carrier protein, DXP nanoparticles induced a restoration of the BRB 1 month after their intravitreal injection. However, their efficacy was limited in time most probably by clearance of DXP nanoparticles after 2 months due to their small size.

Dexamethasone palmitate large porous particles: A controlled release formulation for lung delivery of corticosteroids.

We have optimized a formulation of a prodrug of dexamethasone (DXM), dexamethasone palmitate (DXP) for pulmonary delivery as a dry powder. Formulations were prepared by spray drying DXP with 1,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine (DPPC) and Hyaluronic Acid (HA) as excipients. Large porous particles around 13 µm were produced with a tap density of 0.05g/cm3 and a Fine particle fraction around 40%. The palmitate moiety favors DXP insertion into DPPC bilayers therefore limiting its in vitro release as shown by differential scanning calorimetry. After administering DXP powder intratracheally to rats by insufflation, bronchoalveolar lavage fluid (BALF) and blood samples were collected up to 24h and DXP and DXM concentrations were determined by HPLC analysis after extraction. PK parameters were evaluated according to a non-compartmental model. We observe that DXP remains for up to 6h in the epithelial lining fluid (ELF) of the lungs at very high concentration. In addition, DXP concentration decreases according to two characteristic times. Consequently, DXM can be detected at rather important concentration in ELF up to 24h. The passage of DXP from the lungs to the bloodstream is very poor whereas DXM seems to be absorbed in the blood more easily. These results suggest that once administered DXP undergoes two different processes: hydrolysis into DXM due to the presence of esterases in the lungs and distribution in the lung tissue. This formulation appears promising to reduce systemic exposure and prolong the effect of the drug locally.

Paclitaxel-loaded PEGylated nanocapsules of perfluorooctyl bromide as theranostic agents.

We optimize the encapsulation of paclitaxel (PTX) into nanocapsules made of a shell of poly(lactide-co-glycolide)-polyethylene glycol and a core of perfluorooctyl bromide (PFOB) to serve as theranostic agents. Two main challenges were met: keeping the imaging moiety (PFOB) encapsulated while loading the polymer shell with a hydrophobic drug very prone to crystallization. Encapsulation is performed by a modified emulsion-evaporation method leading to 120nm diameter nanocapsules with a drug loading compatible with tumor treatment. The optimized formulation tested in vitro on CT-26 colon cancer cells yields a similar IC50 as the generic Taxol® formulation. In vivo, 19F-MRI shows that PTX encapsulation does not modify the ability of nanocapsules to accumulate passively in CT-26 tumors in mice by the enhanced permeation and retention (EPR) effect. This accumulation leads to a promising and statistically significant twofold reduction in tumor growth as compared with negative control and generic Taxol® group. Altogether these results advocate for an interesting potential of these paclitaxel-loaded theranostic agents.

Hyaluronic acid liposomal gel sustains delivery of a corticoid to the inner ear.

The inner ear is one of the most challenging organs for drug delivery, mainly because of the blood-perilymph barrier. Therefore, local rather than systemic drug delivery methods are being developed for inner ear therapy. In this work, we have evaluated the benefit of a hyaluronic acid liposomal gel for sustained delivery of a corticoid to the inner ear after local injection into the middle ear in a guinea pig model. The liposomal gel was easily injectable as a result of the shear-thinning behavior of hyaluronic acid. A prolonged residence time at the site of injection as well as in the round window were achieved without any negative effect on the hearing thresholds of the animals. The presence of liposomes in the formulation resulted in sustained release of the drug in the perilymph for 30days and promoted the conversion of the prodrug loaded within the liposomes (dexamethasone phosphate) into its active form (dexamethasone). In this way, therapeutic doses were attained in the perilymph. A small amount of intact liposomes was visualized in the perilymph, whereas the main proportion of liposomes seemed to be trapped in the round window resulting in a reservoir effect. Thus, the administration of hyaluronic acid liposomal gel to the middle ear is an efficient strategy for delivering corticoids to the inner ear in a sustained manner.

Pulmonary delivery of pyrazinamide-loaded large porous particles.

We have improved the aerodynamic properties of pyrazinamide loaded large porous particles (PZA-LPPs) designed for pulmonary delivery. To overcome the segregation of the different components occurring during the spray drying process and to obtain homogeneous LPPs, spray drying parameters were modified to decrease the drying speed. As a result, good aerodynamic properties for lung delivery were obtained with a fine particle fraction (FPF) of 40.1±1.0%, an alveolar fraction (AF) of 29.6±3.1%, a mass median aerodynamic diameter (MMADaer) of 4.1±0.2µm and a geometric standard deviation (GSD) of 2.16±0.16. Plasma and epithelial lining fluid (ELF) concentrations of pyrazinamide were evaluated after intratracheal insufflation of PZA-LPPs (4.22mgkg(-1)) into rats and compared to intravenous administration (iv) of a pyrazinamide solution (5.82mgkg(-1)). The in vivo pharmacokinetic evaluation of PZA-LPPs in rats reveals that intratracheal insufflation of PZA-LPPs leads to a rapid absorption in plasma with an absolute bioavailability of 66%. This proves that PZA-LPPs dissolve fast upon deposition and that PZA crosses efficiently the lung barrier to reach the systemic circulation. PZA concentrations were 1.28-fold higher in ELF after intratracheal administration than after iv administration and the ratio of ELF concentrations over plasma concentrations was 2-fold greater. Although these improvements are moderate, lung delivery of PZA appears an interesting alternative to oral delivery of the molecule and should now be tested in an infected animal model to evaluate its efficacy against Mycobacterium tuberculosis.

Investigation of the complexation of albendazole with cyclodextrins for the design of new antiparasitic formulations.

Albendazole (ABZ) exhibits a potent antiparasitic activity against a broad spectrum of parasites. Unfortunately, the very low water solubility of ABZ (0.2 µg mL(-1), 0.7 µM) impairs considerably its formulation. Phase solubility diagrams showed that α-cyclodextrin (10% w/w), hydroxypropyl-ß-cyclodextrin (40% w/w) and sulfobutylether-ß-cyclodextrin (40% w/w) allowed an increase of apparent solubility with enhancement factors of 570, 3970, and 5880, respectively. The apparent aqueous solubility of ABZ was markedly increased from 0.2 µg mL(-1) (0.7 µM) without cyclodextrins to 1.52 mg mL(-1) (5.69 mM) with random methyl-ß-cyclodextrin (Me-ß-CD) (40% w/w). This corresponds to an apparent solubility enhancement factor of 7600 which is the maximal enhancement factor of ABZ apparent aqueous solubility ever reported in the literature using conventional cyclodextrins. The complexation mechanism between ABZ and cyclodextrins has been investigated using phase solubility diagrams, nuclear magnetic resonance ((1)H NMR) coupled with two-dimensional nuclear Overhauser effect (NOESY) experiments and molecular docking calculations. The results showed that the central bicyclic fragment from ABZ interacts with Me-ß-CD according to 1:1 stoichiometry.

HPLC quantification of doxorubicin in plasma and tissues of rats treated with doxorubicin loaded poly(alkylcyanoacrylate) nanoparticles.

The long-term clinical use of doxorubicin (Dox), one of the most important anticancer agent in use, is limited by dose-related acute cardiotoxicity, myelo-suppression and multidrug resistance developed by cancer cells. To improve the antitumor efficacy and reduce the toxicity of Dox, many drug delivery systems have been developed, including poly(alkylcyanoacrylate) (PACA) nanoparticles. A new formulation of PACA nanoparticles with potential stealth properties were prepared by redox radical emulsion polymerization and associated to Dox in our laboratory. To comparatively investigate the pharmacokinetics and the biodistribution of different formulations of Dox associated PACA nanoparticles, a simple and rapid high performance liquid chromatographic method (HPLC) was developed for the quantification of Dox in plasma and tissues of rats treated with Dox loaded PACA nanoparticle (Dox-PACA). Dox was eluted at 4.4 min and it was well separated from its main metabolites doxorubicinol (Doxl) and doxorubicinon (Doxon) and idarubicin (Ida) used as internal standard (IS). Extraction of Dox from biological media was achieved by liquid-liquid extraction. The recovery of total Dox (i.e. free Dox and Dox associated with nanoparticles) from plasma and tissues (liver, spleen and heart) spiked with Dox-PACA were 71 and 78% for 0.05 and 1 µg/mL in rat plasma, respectively, and 73% and 80% for 0.5 and 10 µg/g in tissues, respectively. The method is linear from 0.05 to 1.5 µg/mL of Dox in plasma. The limit of detection of the method is 0.5 ng of Dox per injection (50 µL). The between-day and within-day precisions of the method were 97.1-102.9% and 97.3-101.7% for concentrations ranging from 0.05 to 1 µg/mL, respectively. Preliminary data suggested that this method can be applied to determine the pharmacokinetic and biodistribution of Dox associated with PACA nanoparticles after intravenous administration to rats.

Intestinal permeation enhancement of docetaxel encapsulated into methyl-ß-cyclodextrin/poly(isobutylcyanoacrylate) nanoparticles coated with thiolated chitosan.

In this study we investigated the potential of mucoadhesive nanoparticles to enhance the intestinal permeability of docetaxel (Dtx). These nanoparticles were composed of methyl-ß-cyclodextrin (Me-ß-CD) combined with poly(isobutylcyanoacrylate) and coated with thiolated chitosan. In order to encapsulate the highest amount of Dtx into nanoparticles, the anionic emulsion polymerization of isobutylcyanoacrylate was carried out in a solution of Me-ß-CD/Dtx inclusion complex. The resulting nanoparticles were spherical with diameters ranging from 200 to 400 nm, and positively charged. Depending on the formulation, the encapsulation efficiency of Dtx was 70-80%. In vitro experiments in simulated intestinal medium containing 1% w/v of pancreatin showed that Dtx was gradually released to reach 60% after 24h and 100% after 48 h. The capacity of these nanoparticles to enhance the flux of Dtx across the intestinal membrane was then investigated using the Ussing chamber technique. The intestinal permeation of Dtx loaded into nanoparticles was found to be higher than the ethanol control solution of Dtx. Interestingly, when mucoadhesive interactions between nanoparticles and the mucosa were avoided, the intestinal permeation of Dtx significantly decreased, confirming that the mucoadhesion of the nanoparticles was a mandatory condition to enhance the intestinal permeation of Dtx.

Conformation of surface-decorating dextran chains affects the pharmacokinetics and biodistribution of doxorubicin-loaded nanoparticles.

Recent reports showed that subtle modifications of nanoparticle surface properties induced dramatic changes of interactions with serum proteins. The present work was aimed to investigate the effect of the conformation of dextran chains decorating the surface of poly(alkylcyanoacrylate) (PACA) nanoparticles on the pharmacokinetic and biodistribution of a model drug associated with the nanoparticles. Doxorubicin was associated with PACA nanoparticles prepared by anionic emulsion polymerization (AEP) (Dox-AEP) and redox radical emulsion polymerization (RREP) (Dox-RREP). Nanoparticles and the free drug (f-Dox) were injected intravenously to rats to determine the pharmacokinetic and biodistribution of doxorubicin. Curves of the pharmacokinetics showed a rapid phase of distribution followed by a slower elimination phase. Pharmacokinetic parameters of the distribution phase determined for the Dox-RREP were significantly different from those of f-Dox and Dox-AEP, while no difference was observed in the elimination phase of the three formulations. Rats treated with Dox-RREP showed lower Dox concentrations in liver but higher concentrations in heart, lungs, and kidneys compared to those treated with the other formulations. Dox-RREP exhibited a new type of stealth behavior characterized by a short circulation time and a rapid distribution in highly vascularized organs bypassing the MPS. The difference in pharmacokinetic and biodistribution observed between the drugs formulated with the two types of nanoparticles was attributed to the difference in the conformation of the dextran chains stranded on the nanoparticle surface.

Controlled release of a highly hydrophilic API from lipid microspheres obtained by prilling: analysis of drug and water diffusion processes with X-ray-based methods.

This study deals with the development of an oral controlled-release dosage form of a highly water-soluble antiepileptic drug. In this respect, drug-loaded spheroid particles close to 380 µm in diameter and composed of lipid binders were prepared by prilling. The purpose here was to thoroughly characterize the controlled-release mechanism of the drug in aqueous pH-6.8 buffered dissolution medium. Water and drug diffusion pathways as well as related kinetic parameters were determined by theoretical analysis of experimental data. Conventional in-vitro experiments performed by analytical high performance liquid chromatography showed that the released fraction reaches 90 wt.% only after a 24-hour immersion in the dissolution medium, pointing out an effective sustained release mechanism. Interpretation of these data was strengthened by the implementation of an innovative methodology involving X-ray diffraction and microtomography to follow the structural evolution of the drug-loaded microspheres at molecular and microscopic scales. This approach allowed to explicit that water and drug transports obey to Fickian diffusion behaviours in good agreement with Crank's and non-simplified Higuchi's equations, respectively. In the latter case, independent modelling of drug release assimilating the microspheres to a variable-geometry reservoir was considered to refine the kinetic analysis of the diffusion process. The water diffusion coefficient D(w) was found equal to 6.3 × 10(-9) cm(2)/s and the API apparent diffusion coefficient reduced to the tortuosity of the matrix D(API)/τ equal to 2 × 10(-9) cm(2)/s. This study ranks among the rare examples of monolithic dispersion device constituted by a highly soluble drug incorporated inside a perfectly inert lipid matrix. The dissolution liquid penetrates the particles through channels progressively created by the solubilization of the drug itself which occurs instantaneously at the inner front of the liquid.

Aerosolized liposomal amphotericin B: prediction of lung deposition, in vitro uptake and cytotoxicity.

To predict the efficacy and toxicity of pulmonary administration of liposomal amphotericin B (L-AMB) for the treatment or the prevention of pulmonary invasive aspergillosis, a multistage liquid impinger was used to estimate the concentrations of drug that could be attained in different lung compartments after nebulization. The highest concentration of amphotericin B was found in the alveolar compartment, where it was calculated that the concentration in the lung surfactant could reach 54 µM or more when 21.6 µmoles of drug as liposomes was nebulized. The uptake and toxicity of L-AMB were studied in vitro using the A549 human lung epithelial cell line. Uptake was time and concentration-dependent and reached intracellular concentrations exceeding the minimal inhibitory concentrations for most Aspergillus species. The toxicity of L-AMB toward these cells, estimated by the MTT reduction assay, was reduced compared with the conventional form, deoxycholate amphotericin B (D-AMB), with an IC(50) value of about 120 µM after 24 h of exposure for D-AMB, but only a 13% reduction in viability for 200 µM L-AMB at 24 h. These results indicate that aerosol therapy with nebulized L-AMB could be efficient but that doses need to be carefully controlled to avoid toxicity.

Long-circulating perfluorooctyl bromide nanocapsules for tumor imaging by 19FMRI.

PLGA-PEG nanocapsules containing a liquid core of perfluorooctyl bromide were synthesized by an emulsion-evaporation process and designed as contrast agents for (19)F MRI. Physico-chemical properties of plain and PEGylated nanocapsules were compared. The encapsulation efficiency of PFOB, estimated by (19)F NMR spectroscopy, is enhanced when using PLGA-PEG instead of PLGA. PLGA-PEG nanocapsule diameter, measured by Dynamic Light Scattering is around 120 nm, in agreement with Transmission Electron microscopy (TEM) observations. TEM and Scanning Electron Microscopy (SEM) reveal that spherical core-shell morphology is preserved. PEGylation is further confirmed by Zeta potential measurements and X-ray Photoelectron Spectroscopy. In vitro, stealthiness of the PEGylated nanocapsules is evidenced by weak complement activation. Accumulation kinetics in the liver and the spleen was performed by (19)F MRI in mice, during the first 90 min after intravenous injection. In the liver, plain nanocapsules accumulate faster than their PEGylated counterparts. We observe PEGylated nanocapsule accumulation in CT26 xenograft tumor 7 h after administration to mice, whereas plain nanocapsules remain undetectable, using (19)F MRI. Our results validate the use of diblock copolymers for PEGylation to increase the residence time of nanocapsules in the blood stream and to reach tumors by the Enhanced Permeation and Retention (EPR) effect.

Bivalent sequential binding of docetaxel to methyl-ß-cyclodextrin.

New docetaxel (Dtx) and cyclodextrin (CD) inclusion complexes having improved apparent water solubility (up to 9.98mgmL(-1)) were obtained from phase solubility diagrams. γ-CD and SBE-ß-CD offered only poor solubility enhancements while considerable increases in apparent solubility were obtained with Me-ß-CD (20%, w/w) and HP-ß-CD (40%, w/w) (9.98mgmL(-1) and 7.43mgmL(-1), respectively). The complexation mechanism between Dtx and Me-ß-CD was investigated by circular dichroism spectrometry, two-dimensional (1)H NMR (NOESY) in D(2)O, isothermal titration calorimetry (ITC) and molecular docking calculations. Circular dichroism and NOESY confirmed the existence of non-covalent interactions between Dtx and Me-ß-CD and suggested that the tert-butyl group (C(6)-C(9)) and two aromatic groups (C(24)-C(29) and C(30)-C(35)) of Dtx interacted with the Me-ß-CD molecules. The combination of ITC results to molecular docking calculations led to the identification of an unconventional sequential binding mechanism between Me-ß-CD and Dtx. In this sequential binding, a Me-ß-CD molecule first interacted with both tert-butyl and C(30)-C(35) aromatic groups (K(1): 744M(-1)). Then a second Me-ß-CD molecule interacted with the C(24)-C(29) aromatic group (K(2): 202M(-1)). The entropy of the first interaction was positive, whereas a negative value of entropy was found for the second interaction. The opposite behavior observed for these two sites was explained by differences in the hydrophobic contact surface and functional group flexibility.

Influence of surface charge on the potential toxicity of PLGA nanoparticles towards Calu-3 cells.

BACKGROUND: Because of the described hazards related to inhalation of manufactured nanoparticles, we investigated the lung toxicity of biodegradable poly (lactide-co-glycolide) (PLGA) nanoparticles displaying various surface properties on human bronchial Calu-3 cells. METHODS: Positively and negatively charged as well as neutral nanoparticles were tailored by coating their surface with chitosan, Poloxamer, or poly (vinyl alcohol), respectively. Nanoparticles were characterized in terms of size, zeta potential, and surface chemical composition, confirming modifications provided by hydrophilic polymers. RESULTS: Although nanoparticle internalization by lung cells was clearly demonstrated, the cytotoxicity of the nanoparticles was very limited, with an absence of inflammatory response, regardless of the surface properties of the PLGA nanoparticles. CONCLUSION: These in vitro results highlight the safety of biodegradable PLGA nanoparticles in the bronchial epithelium and provide initial data on their potential effects and the risks associated with their use as nanomedicines.

Synthesis, characterization, and in vivo delivery of siRNA-squalene nanoparticles targeting fusion oncogene in papillary thyroid carcinoma.

We report the conjugation of the natural lipid squalene (SQ) with a small interfering RNA (siRNA), against the junction oncogene RET/PTC1, usually found in papillary thyroid carcinoma (PTC). The acyclic isoprenoid chain of squalene has been covalently coupled with siRNA RET/PTC1 at the 3'-terminus of the sense strand via maleimide-sulfhydryl chemistry. Remarkably, the linkage of siRNA RET/PTC1 to squalene led to an amphiphilic molecule that self-organized in H(2)O as siRNA-SQ RET/PTC1 nanoparticles (NPs). The siRNA-SQ RET/PTC1 NPs, stable in H(2)O, were used for biological studies. In vitro, they did not show any cytotoxicity. Interestingly, in vivo, on a mice xenografted RET/PTC1 experimental model, RET/PTC1-SQ NPs were found to inhibit tumor growth and RET/PTC1 oncogene and oncoprotein expression after 2.5 mg/kg cumulative dose intravenous injections. In conclusion, these results showed that the "squalenoylation" offers a new noncationic plate-form for the siRNA delivery.