Purification processes of polymeric nanoparticles: How to improve their clinical translation?

Polymeric nanoparticles, as revolutionary nanomedicines, have offered a new class of diagnostic and therapeutic solutions for a multitude of diseases. With its immense potential, the world witnesses the new age of nanotechnology after the COVID-19 vaccines were developed based on nanotechnology. Even though there are countless benchtop research studies in the nanotechnology world, their integration into commercially available technologies is still restricted. The post-pandemic world demands a surge of research in the domain, which leaves us with the fundamental question: why is the clinical translation of therapeutic nanoparticles so restricted? Complications in nanomedicine purification, among other things, are to blame for the lack of transference. Polymeric nanoparticles, owing to their ease of manufacture, biocompatibility, and enhanced efficiency, are one of the more explored domains in organic-based nanomedicines. Purification of nanoparticles can be challenging and necessitates tailoring the available methods in accordance with the polymeric nanoparticle and impurities involved. Though a number of techniques have been described, there are no available guidelines that help in selecting the method to better suit our requirements. We encountered this difficulty while compiling articles for this review and looking for methods to purify polymeric nanoparticles. The currently accessible bibliography for purification techniques only provides approaches for a specific type of nanomaterial or sometimes even procedures for bulk materials, that are not fully relevant to nanoparticles. In our research, we tried to summarize the available purification techniques using the approach of A.F. Armington. We divided the purification systems into two major classes, namely: phase separation-based techniques (based on the physical differences between the phases) and matter exchange-based techniques (centered on physicochemical induced transfer of materials and compounds). The phase separation methods are based on either using nanoparticle size differences to retain them on a physical barrier (filtration techniques) or using their densities to segregate them (centrifugation techniques). The matter exchange separation methods rely on either transferring the molecules or impurities across a barrier using simple physicochemical phenomena, like the concentration gradients (dialysis method) or partition coefficients (extraction technique). After describing the methods in detail, we highlight their advantages and limitations, mainly focusing on preformed polymer-based nanoparticles. Tailoring a purification strategy takes into account the nanoparticle structure and its integrity, the method selected should be suited for preserving the integrity of the particles, in addition to conforming to the economical, material and productivity considerations. In the meantime, we advocate the use of a harmonized international regulatory framework to define the adequate physicochemical and biological characterization of nanomedicines. An appropriate purification strategy serves as the backbone to achieving desired characteristics, in addition to reducing variability. As a result, the present review aspires to serve as a comprehensive guide for researchers, who are new to the domain, as well as a synopsis of purification strategies and analytical characterization methods used in preclinical studies.

New trends for osteoarthritis: Biomaterials, models and modeling.

The burden of osteoarthritis (OA), one of the major causes of functional disabilities in humans and animals, continues to increase worldwide while no disease-modifying OA drugs (DMOADs) that either slow down or reverse disease progression have been made available. Here, we provide a brief overview of recent advances in: designing new OA drug delivery approaches, focusing on lubrication-based biomaterials and drug delivery systems, such as hydrogels, liposomes, dendrimers, micro- and nanoparticles; using either large (horse) or small (zebrafish) relevant animal models to evaluate new therapeutic strategies; and OA in vitro modeling, focusing on 3D (organoid) models of cartilage regarding the Replace, Reduce and Refine (3R) principle of animal experimentation.

Stability evaluation of compounded hydroxyurea 100 mg/mL oral liquids using a novel analytical method involving chemical derivatization.

This study assessed the stability of six extemporaneously compounded hydroxyurea oral liquids stored at room temperature. Hydroxyurea oral liquids (100 mg/mL) were prepared using three different mixing methods (mortar, mixer or QuartetRx) from either bulk powder, capsule content, or whole capsules. Two brands of capsules were tested in this study. All formulations were stored at room temperature (25°C / 60% RH) in amber plastic bottles for 90 days and amber plastic syringes for 14 days. Physical stability was assessed visually, while chemical stability was evaluated using a stability-indicating high-performance liquid chromatography method. Chemical derivatization with xanthydrol allowed the retention of hydroxyurea on a reverse-phase column. At least 93.9% and 97.0% of the initial concentration of hydroxyurea remained after 90 days in bottles and 14 days in syringes, respectively. There were no visual changes in formulations over the study period. Changes in pH up to 1.6 units were observed after 90 days of storage and were explained most likely by an ammonium generating degradation pathway. Ammonium was quantified and remained within safe levels in each HU 100 mg/mL oral preparations. Hydroxyurea oral liquids were all stable for 90 days in amber plastic bottles and 14 days in amber plastic syringes.

Tailoring PEGylated nanoparticle surface modulates inflammatory response in vascular endothelial cells.

Polymer nanoparticles (NPs) are extensively studied as drug delivery systems for various therapeutic indications, including drug and imaging agent delivery to the brain. Despite intensive research, their toxicological profile has yet to be fully characterized. In particular, the more subtle effects of nanomaterials on inflammatory processes have scarcely been investigated. Surface properties of NPs are amongst parameters governing interactions between living cells and NPs. They could considerably influence the toxicity and inflammatory response of the cells exposed to NPs. Polymeric NPs investigated here present a core-shell structure. The core is constituted of hydrophobic poly(lactic acid) (PLA) block and the surface is composed of a shell of hydrophilic block of polyethylene glycol (PEG). The effect of PEG chain length coating on the expression of genes involved in the inflammation response was investigated in two vascular endothelial cell lines (bEnd.3 and HUVEC) by qPCR. Moreover, ROS generation following NP uptake was evaluated. PEGylated NPs induce a mild and transient activation of inflammatory cytokine and chemokine genes. However, differences in PEG chain length did not show any significant effect on cytokine and chemokine gene expression and PEGylated NPs did not trigger ROS generation. The present results could contribute significantly to a deeper understanding of nanomaterial interactions and toxicity with vascular endothelial cells, guiding scientists in material coating choices.

Stability evaluation of compounded clonidine hydrochloride oral liquids based on a solid-phase extraction HPLC-UV method.

The present study aimed to assess the stability of clonidine hydrochloride oral liquids (20-µg/mL) prepared from two different generic tablets in Ora-Blend and stored in amber plastic bottles. Physical and chemical stabilities were evaluated over a period of 90 days at 25°C. Analytical challenges were overcome with the development of a new extraction procedure based on solid phase extraction to ensure efficient clonidine hydrochloride quantification. The absence of physical instabilities, evaluated by qualitative and quantitative measurements (static multiple light scattering), as well as the absence of chemical instabilities, evidenced by a stability-indicating HPLC-UV method, confirmed that a beyond-use date of 90 days was appropriate for these compounded oral liquids.

Lipid Coating of Chitosan Nanogels for Improved Colloidal Stability and In Vitro Biocompatibility.

Chitosan-based carriers have coined their position as delivery agents. When assembled with polyanions into nanogels (NG), these vectors have enabled the delivery of drugs, genes, and proteins to a myriad of applications. However, the chemical and colloidal instability of chitosan nanoformulations in physiologically compatible media prejudices in vitro biocompatibility and, thus, scale-up applications. To overcome this issue, we envisaged the coating of chitosan nanogel with phospholipids. In this investigation, we report a two-stage synthesis of hybrid lipid-coated chitosan nanogels, named nanolipogels (NLG), to improve colloidal stability and in vitro biocompatibility over chitosan NG. Practically, we employed a mixing platform to first prepare chitosan NG by ionic gelation, dilute the suspension, and, in a second stage, coat the NG with lipids. We demonstrate that lipid coating increased particle size and reversed the ζ-potential to negative values, suggesting the successful formation of NLG, while maintaining a homogeneous size distribution (PDI < 0.25). Furthermore, multiple light scattering analysis confirmed NLG improved colloidal stability in phosphate buffer saline and cell culture medium, with respect to NG. Finally, lipid coating completely abrogated the cytotoxicity of NG when incubated at 50 µg·mL-1 with HeLa, U87, or b.End3 cell lines and significantly improved the biocompatibility at 100 and 150 µg·mL-1. Future investigations will explore how the lipid coating affects drug loading, release profile, and the ability of NLG to deliver drugs and genes in vitro.

Preparation and characterization of 12-HSA-based organogels as injectable implants for the controlled delivery of hydrophilic and lipophilic therapeutic agents.

Organogels prepared with low molecular weight organogelators to structure liquid oils represent excellent matrices for the controlled delivery of a wide variety of drug molecules. Although studies on organogel systems are reported in the literature, relatively few investigate their potential as gels formed in situ intended for drug delivery. This study reports the development of injectable subcutaneous 12- hydroxystearic acid (12-HSA) organogels for the delivery of both lipophilic and hydrophilic drugs. The rheological characterization (flow, dynamic temperature ramp and amplitude oscillatory measurements) and physicochemical properties (syringeability, swelling and degradation studies), as well as permeability and cytotoxicity were analyzed to gain insights into the influence of the gel composition (surfactant addition, organogelator concentration) on the gelation process and organogel properties. Sol-gel phase transition temperature (Tgel) and gel-sol phase transition temperature (Tmelt) were determined by the tube-inverting method and complementary rheology studies. An increase in 12-HSA concentration led to an augmentation in gel strength and storage (G') and loss (G″) moduli values, evidencing the self-assembly of crystalline gelator structure entrapping the oil phase into a three-dimensional (3D) network. The addition of polysorbate 80 (Tween 80, T80) surfactant molecules in the system caused a weaker gel-like structure, with lower flow rate during syringeability assays, despite its lower apparent viscosity compared to those of 12-HSA organogels. In addition, the swelling studies of 12-HSA/12-HSA T80 organogels as a function of time in phosphate buffered saline (PBS) revealed that the erosion rates were modulated by the organogel compositions. The permeability of acyclovir (ACV) and clotrimazole (CTM), hydrophilic and lipophilic model drugs, respectively, loaded in 12-HSA-based organogels, was assessed in Franz diffusion cells. Organogel-loaded drugs presented lower in vitro release rates and ex vivo drug permeabilities compared to the corresponding drug solutions. Furthermore, 12-HSA T80 organogel could slow down the release of ACV by a factor of about 2.6-fold, up to 6 h, compared to CTM-loaded 12-HSA organogels. Finally, the cytotoxicity of 12-HSA-based organogels was evaluated through in vitro cell viability assays in human foreskin fibroblasts (HFF). Increased 12-HSA concentration resulted in higher cytotoxic effect, with a higher test sensitivity observed for the 3D collagen-embedded cell layer setup matrix versus 2-D cell cultures. Our results support the hypothesis that 12-HSA-based organogels are promising systems for controlled drug delivery as in situ-forming implants.

Erratum: Puscas, I.; et al. IVIVC Assessment of Two Mouse Brain Endothelial Cell Models for Drug Screening. Pharmaceutics 2019, 11, 587.

The authors wish to make the following corrections to this paper [...].

Isolation of endothelial cells, pericytes and astrocytes from mouse brain.

Primary cell isolation from the central nervous system (CNS) has allowed fundamental understanding of blood-brain barrier (BBB) properties. However, poorly described isolation techniques or suboptimal cellular purity has been a weak point of some published scientific articles. Here, we describe in detail how to isolate and enrich, using a common approach, endothelial cells (ECs) from adult mouse brains, as well as pericytes (PCs) and astrocytes (ACs) from newborn mouse brains. Our approach allowed the isolation of these three brain cell types with purities of around 90%. Furthermore, using our protocols, around 3 times more PCs and 2 times more ACs could be grown in culture, as compared to previously published protocols. The cells were identified and characterized using flow cytometry and confocal microscopy. The ability of ECs to form a tight monolayer was assessed for passages 0 to 3. The expression of claudin-5, occludin, zonula occludens-1, P-glycoprotein-1 and breast cancer resistance protein by ECs, as well as the ability of the cells to respond to cytokine stimuli (TNF-α, IFN-γ) was also investigated by q-PCR. The transcellular permeability of ECs was evaluated in the presence of pericytes or astrocytes in a Transwell® model by measuring the transendothelial electrical resistance (TEER), dextran-FITC and sodium fluorescein permeability. Overall, ECs at passages 0 and 1 featured the best properties valued in a BBB model. Furthermore, pericytes did not increase tightness of EC monolayers, whereas astrocytes did regardless of their seeding location. Finally, ECs resuspended in fetal bovine serum (FBS) and dimethyl sulfoxide (DMSO) could be cryopreserved in liquid nitrogen without affecting their phenotype nor their capacity to form a tight monolayer, thus allowing these primary cells to be used for various longitudinal in vitro studies of the blood-brain barrier.

IVIVC Assessment of Two Mouse Brain Endothelial Cell Models for Drug Screening.

Since most preclinical drug permeability assays across the blood-brain barrier (BBB) are still evaluated in rodents, we compared an in vitro mouse primary endothelial cell model to the mouse b.End3 and the acellular parallel artificial membrane permeability assay (PAMPA) models for drug screening purposes. The mRNA expression of key feature membrane proteins of primary and bEnd.3 mouse brain endothelial cells were compared. Transwell® monolayer models were further characterized in terms of tightness and integrity. The in vitro in vivo correlation (IVIVC) was obtained by the correlation of the in vitro permeability data with log BB values obtained in mice for seven drugs. The mouse primary model showed higher monolayer integrity and levels of mRNA expression of BBB tight junction (TJ) proteins and membrane transporters (MBRT), especially for the efflux transporter Pgp. The IVIVC and drug ranking underlined the superiority of the primary model (r2 = 0.765) when compared to the PAMPA-BBB (r2 = 0.391) and bEnd.3 cell line (r2 = 0.019) models. The primary monolayer mouse model came out as a simple and reliable candidate for the prediction of drug permeability across the BBB. This model encompasses a rapid set-up, a fair reproduction of BBB tissue characteristics, and an accurate drug screening.

Development of a safe and versatile suspension vehicle for pediatric use: Formulation development.

This project aimed to develop a suspension vehicle specifically designed for pediatric use. Excipients were selected according to their safety and recorded use in pediatrics. Two suspension vehicles were formulated at neutral and acidic pH. A few compositions were defined, and their physicochemical properties assessed and compared to readily-available commercial vehicles. As required for a multidose oral formulation, an antimicrobial effectiveness test was conducted according to the USP. Different microbial strains were inoculated individually in each formulation and their concentrations monitored for 28 days. Propionic acid proved to be an effective preservative against all tested strains at pH 4.5. All tested preservative failed the test at pH 7.5. The final version of the novel vehicle presented a pH of 4.5 and a viscosity of 85 cP at 25 °C. A clear shear-thinning behaviour could be observed. These properties warranted an adequate physical stability and resuspendability, when tested with prednisolone and acetaminophen tablets. A slight reduction of the viscosity was reported when stored at room temperature, but the pH remained constant for 180 days in refrigerated conditions and at room temperature. The final result is a ready-to-use compounding vehicle, containing minimal excipients, safe for children's use and stable for 6 months.

PLGA nanoparticles optimized by Box-Behnken for efficient encapsulation of therapeutic Cymbopogon citratus essential oil.

This study aimed to optimize Cymbopogon citratus essential oil loaded into PLGA-nanoparticles by investigating the effect of processing variables (sonication time, ultrasound power, and essential oil/polymer ratio) on encapsulation efficiency and particle mean hydrodynamic diameter using Box-Behnken design. Nanoparticles were prepared by an emulsification/solvent diffusion method and physicochemically characterized by FTIR, DSC and TGA/DTA. Cytotoxicity was evaluated in human HaCat keratinocytes by WST-1 and LDH assays. The optimized formulation had a hydrodynamic mean diameter of 277 nm, a polydispersity index of 0.18, a Zeta potential of -16 mV and an encapsulation efficiency of 73%. Nanoparticle characterization showed that only citral was incorporated in nanocarriers, with some amount adsorbed on their surface, and highlighted the potential in increasing the oil thermal stability. The drug release profile demonstrated a biphasic pattern with a substantial sustained release depending on diffusion from the polymeric matrix. Toxicity effects on cell viability of pure essential oil at low concentrations were significantly eliminated when encapsulated. Results revealed the ability of PLGA-nanoparticles to improve essential oil physicochemical characteristics, by controlling release and reducing toxicity, suggesting their potential use in pharmaceutical preparations.

Tailored Nanocarriers for the Pulmonary Delivery of Levofloxacin against Pseudomonas aeruginosa: A Comparative Study.

Cystic fibrosis (CF) patients are faced with chronic bacterial infections displaying persistent resistance if not eradicated during the first stage of the disease. Nanoantibiotics for pulmonary administration, such as liposomal ciprofloxacin or amikacin, have progressed through clinics thanks to their sustained release, prolonged lung residence time, and low systemic absorption. In this work, we sought a nanoformulation of levofloxacin for the treatment of Pseudomonas aeruginosa. We prepared and compared poly(lactic acid)-grafted-poly(ethylene glycol) nanoparticles, as well as anionic and cationic liposomes for their size, charge, and encapsulation efficiency. Cationic liposomes were unable to encapsulate any drug and were subsequently considered as a control formulation. Regarding the efficiency of the nanocarrier, anionic liposomes exhibited a prolonged release over 72 h and preserved the antibacterial activity of levofloxacin against five strains of P. aeruginosa, whereas polymeric nanoparticles quickly released their entire payload and increased the minimum inhibitory concentration of levofloxacin. Thus, only anionic liposomes were considered for further preclinical development. Anionic liposomes exhibited a suitable colloidal stability in Turbiscan analysis and crossed a layer of artificial mucus in under 1 h in a Transwell setup. Despite their negative surface charge, liposomes still interacted with the P. aeruginosa membrane in a dose-response manner, as demonstrated by flow cytometry. Viability assays confirmed that anionic liposomes, loaded or not, exhibited a good safety profile on A549 epithelial cells, even at high concentrations. Finally, nebulization of anionic liposomes containing levofloxacin did not impact their colloidal stability, and the droplet size distribution was suitable for deep lung deposition, where the P. aeruginosa infection lies. Therefore, levofloxacin-loaded anionic liposomes exhibited suitable properties for the pulmonary treatment of P. aeruginosa in CF. This step-by-step study confirms the promising role of liposomes for lung administration of antibiotics, as recently seen in clinics, and fosters their development for several types of antibiotics.

Length of surface PEG modulates nanocarrier transcytosis across brain vascular endothelial cells.

Diblock PLA-PEG nanoparticles were produced to establish the role of PEG chain length on brain vascular endothelial cell transcytosis. 100-nm nanoparticles tagged with fluorescent pyrene butanol and coated with PEG chains (Mw: 1-10 kDa), at similar PEG surface density, were used to study endocytosis and transcytosis phenomena on mouse vascular endothelial cell monolayers. The transport mechanisms were then investigated through inhibitory processes. Our results show that there is an evident correlation between PEG chain length and nanoparticle translocation. The highest transcytosis rates were obtained with PEG5000 and PEG10000 and macropinocytosis appeared to play a central role in cell uptake. This study constitutes the first systematic exploration of the role of PEG chain length on nanoparticle endocytosis and transcytosis in an in vitro model of the blood-brain barrier.

Quantification of peptides in human synovial fluid using liquid chromatography-tandem mass spectrometry.

A method to explore the stability of two anti-inflammatory peptides in human synovial fluid (HSF) has been developed and validated using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The two peptides are BQ123 Cyclo(-D-Trp-D-Asp-L-Pro-D-Val-L-Leu, Mw = 610.7) and R-954 (AcOrn[Oic2, (αMe)Phe5, DßNal7, Ile8]desArg9-bradykinin, Mw = 1194.4). Human synovial fluid samples were analyzed after a protein precipitation step with acetonitrile and dilution with mobile phase. DMSO was used as anti-adsorptive agent. We used an octyl silane column with formic acid (0.1%, v/v) in water as the aqueous mobile phase and acetonitrile isopropanol-formic acid (20:80, 0.1 v/v) as the organic mobile phase and 0.7 mL/min flow rate. The peptides CY-771 and pepstatin A were used as internal standards. Selective detection was performed by tandem mass spectrometry with a heated electrospray source (HESI), operated in positive ionization mode and in selected reaction monitoring acquisition (SRM). The method limit of quantification (injection volume = 10 µL) was 0.17 ng and 1.2 ng, corresponding to 28 and 102 nmol L-1 for BQ123 and R-954 respectively in human synovial fluid. Calibration curves obtained using matrix-matched calibration standards and internal standard were linear from 20 to 1000 nmol L-1. Precision values (%R.S.D.) were ≤ 14% in the entire linear range. Accuracy measured at a low and a high concentration level ranged from 93.1% to 102%. The recoveries (at 800 nmol L-1) were 96.4% for BQ123 and 102.0% for R-954. The method was successfully applied to follow the degradation kinetics of both peptides in human synovial fluid from arthritic patients during 72 h.

Organogels, promising drug delivery systems: an update of state-of-the-art and recent applications.

Organogels are semi-solid systems with an organic liquid phase immobilized by a three-dimensional network composed of self-assembled, crosslinked or entangled gelator fibers. Organogel applications are various, including chemistry, pharmaceuticals, cosmetics, biotechnologies and food technology. In pharmacology, they are used as drug and vaccine delivery platforms for active ingredients via diverse routes such as transdermal, oral and parenteral. In a close past, their uses as drug delivery systems have been unfortunately hampered by the toxicity of the selected organic solvents. More recently, the synthesis of more biocompatible organogels has strengthened the development of several biomedical and pharmaceutical applications. This review provides a global view of organogels, such as nature, syntheses, characterizations and properties. An emphasis is placed on the most recent technologies used in the design of organogels as potential controlled delivery systems. A particular attention is provided to their newest therapeutic applications.

Stability of gabapentin in extemporaneously compounded oral suspensions.

This study reports the stability of extemporaneously prepared gabapentin oral suspensions prepared at 100 mg/mL from bulk drug and capsules in either Oral Mix or Oral Mix SF suspending vehicles. Suspensions were packaged in amber plastic bottles and amber plastic syringes at 25°C / 60%RH for up to 90 days. Throughout the study period, the following tests were performed to evaluate the stability of the preparations: organoleptic inspection to detect homogeneity, color or odor changes; pH measurements; and gabapentin assay using a stability-indicating HPLC-UV method. As crystallization was observed at 5°C, storage at this temperature condition is not recommended. All preparations stored at 25°C / 60%RH remained stable for the whole study duration of 90 days.

Stability of Diazoxide in Extemporaneously Compounded Oral Suspensions.

The objective of this study was to evaluate the stability of diazoxide in extemporaneously compounded oral suspensions. Oral suspensions of diazoxide 10 mg/mL were prepared from either bulk drug or capsules dispersed in either Oral Mix or Oral Mix Sugar Free. These suspensions were stored at 5°C and 25°C/60%RH in bottles and oral syringes for a total of 90 days. At predetermined time intervals, suspensions were inspected for homogeneity, color or odor change; the pH was measured and the concentration of diazoxide was evaluated by ultraviolet detection using a stability-indicating high pressure liquid chromatography method. All preparations were demonstrated to be chemically stable for at least 90 days.

Neuronal Uptake and Neuroprotective Properties of Curcumin-Loaded Nanoparticles on SK-N-SH Cell Line: Role of Poly(lactide-co-glycolide) Polymeric Matrix Composition.

Curcumin, a neuroprotective agent with promising therapeutic approach has poor brain bioavailability. Herein, we demonstrate that curcumin-encapsulated poly(lactide-co-glycolide) (PLGA) 50:50 nanoparticles (NPs-Cur 50:50) are able to prevent the phosphorylation of Akt and Tau proteins in SK-N-SH cells induced by H2O2 and display higher anti-inflammatory and antioxidant activities than free curcumin. PLGA can display various physicochemical and degradation characteristics for controlled drug release applications according to the matrix used. We demonstrate that the release of curcumin entrapped into a PLGA 50:50 matrix (NPs-Cur 50:50) is faster than into PLGA 65:35. We have studied the effects of the PLGA matrix on the expression of some key antioxidant- and neuroprotective-related genes such as APOE, APOJ, TRX, GLRX, and REST. NPs-Cur induced the elevation of GLRX and TRX while decreasing APOJ mRNA levels and had no effect on APOE and REST expressions. In the presence of H2O2, both NPs-Cur matrices are more efficient than free curcumin to prevent the induction of these genes. Higher uptake was found with NPs-Cur 50:50 than NPs-Cur 65:35 or free curcumin. By using PLGA nanoparticles loaded with the fluorescent dye Lumogen Red, we demonstrated that PLGA nanoparticles are indeed taken up by neuronal cells. These data highlight the importance of polymer composition in the therapeutic properties of the nanodrug delivery systems. Our study demonstrated that NPs-Cur enhance the action of curcumin on several pathways implicated in the pathophysiology of Alzheimer's disease (AD). Overall, these results suggest that PLGA nanoparticles are a promising strategy for the brain delivery of drugs for the treatment of AD.

Etoposide encapsulation in surface-modified poly(lactide-co-glycolide) nanoparticles strongly enhances glioma antitumor efficiency.

Etoposide (VP-16) is a hydrophobic anticancer agent inhibiting Topoisomerase II, commonly used in pediatric brain chemotherapeutic schemes as mildly toxic. Unfortunately, despite its appropriate solubilization in vehicle solvents, its poor bioavailability and limited passage of the blood-brain barrier concur to disappointing results requiring the development of new delivery system forms. In this study, etoposide formulated as a parenteral injectable solution (Teva®) was loaded into all-biocompatible poly(lactide-co-glycolide) (PLGA) or PLGA/P188-blended nanoparticles (size 110-130 nm) using a fully biocompatible nanoprecipitation technique. The presence of coprecipitated P188 on encapsulation efficacies and in vitro drug release was investigated. Drug encapsulation was determined using HPLC. Inflammatory response was checked by FACS analysis on human monocytes. Cytotoxic activity of the various simple (Teva®) or double (Teva®-loaded NPs) formulations was studied on the murine C6 and F98 cell lines. Obtained results suggest that, although noninflammatory neither nontoxic by themselves, the use of PLGA and PLGA/P188 nanoencapsulations over pre-existing etoposide formulation could induce a greatly improved cytotoxic activity. This approach demonstrated a promising perspective for parenteral delivery of VP16 and potential development of a therapeutic entity.