Mixed Amphiphilic Polymeric Nanoparticles of Chitosan, Poly(vinyl alcohol) and Poly(methyl methacrylate) for Intranasal Drug Delivery: A Preliminary In Vivo Study

Intranasal (i.n.) administration became an alternative strategy to bypass the blood-brain barrier and improve drug bioavailability in the brain. The main goal of this work was to preliminarily study the biodistribution of mixed amphiphilic mucoadhesive nanoparticles made of chitosan-g-poly(methyl methacrylate) and poly(vinyl alcohol)-g-poly(methyl methacrylate) and ionotropically crosslinked with sodium tripolyphosphate in the brain after intravenous (i.v.) and i.n. administration to Hsd:ICR mice. After i.v. administration, the highest nanoparticle accumulation was detected in the liver, among other peripheral organs. After i.n. administration of a 10-times smaller nanoparticle dose, the accumulation of the nanoparticles in off-target organs was much lower than after i.v. injection. In particular, the accumulation of the nanoparticles in the liver was 20 times lower than by i.v. When brains were analyzed separately, intravenously administered nanoparticles accumulated mainly in the "top" brain, reaching a maximum after 1 h. Conversely, in i.n. administration, nanoparticles were detected in the "bottom" brain and the head (maximum reached after 2 h) owing to their retention in the nasal mucosa and could serve as a reservoir from which the drug is released and transported to the brain over time. Overall, results indicate that i.n. nanoparticles reach similar brain bioavailability, though with a 10-fold smaller dose, and accumulate in off-target organs to a more limited extent and only after redistribution through the systemic circulation. At the same time, both administration routes seem to lead to differential accumulation in brain regions, and thus, they could be beneficial in the treatment of different medical conditions.

A Microscopically Motivated Model for Particle Penetration into Swollen Biological Networks

Biological gels (bio-gels) are hydrated polymer networks that serve diverse biological functions, which often lead to intentional or unintentional exposure to particulate matter. In this work, we derive a microscopically motivated framework that enables the investigation of penetration mechanisms into bio-gels. We distinguish between two types of mechanisms: spontaneous (unforced) penetration and forced penetration. Using experimental data available in the literature, we exploit the proposed model to characterize and compare between the microstructures of respiratory, intestinal, and cervicovaginal mucus and two types of biofilms. Next, we investigate the forced penetration process of spherical and ellipsoidal particles into a locally quadrilateral network. The proposed framework can be used to improve and complement the analysis of experimental findings in vitro, ex vivo, and in vivo. Additionally, the insights from this work pave the way towards enhanced designs of nano-medicines and allow the assessment of risk factors related to the nano-pollutants exposure.

The Nose-To-Brain Transport of Polymeric Nanoparticles Is Mediated by Immune Sentinels and Not by Olfactory Sensory Neurons

The nose-to-brain (N-to-B) transport mechanism of nanoparticles through the olfactory epithelium (OE) is not fully understood. Most research utilized nasal epithelial cell models completely deprived of olfactory cells. Aiming to shed light into key cellular pathways, in this work, for the first time, the interaction of polymeric nanoparticles in a 17-483 nm size range and with neutral and negatively and positively charged surfaces with primary olfactory sensory neurons, cortical neurons, and microglia isolated from olfactory bulb (OB), OE, and cortex of newborn rats is investigated. After demonstrating the good cell compatibility of the different nanoparticles, the nanoparticle uptake by confocal laser scanning fluorescence microscopy is monitored. Our findings reveal that neither olfactory nor forebrain neurons internalize nanoparticles. Conversely, it is demonstrated that olfactory and cortical microglia phagocytose the nanoparticles independently of their features. Overall, our findings represent the first unambiguous evidence of the possible involvement of microglia in N-to-B nanoparticle transport and the unlikely involvement of neurons. Furthermore, this approach emerges as a completely new experimental tool to screen the biocompatibility, uptake, and transport of nanomaterials by key cellular players of the N-to-B pathway in nanosafety and nanotoxicology and nanomedicine.

Oral Pharmacokinetics of a Chitosan-Based Nano- Drug Delivery System of Interferon Alpha

Interferon alpha (IFNα) is a protein drug used to treat viral infections and cancer diseases. Due to its poor stability in the gastrointestinal tract, only parenteral administration ensures bioavailability, which is associated with severe side effects. We hypothesized that the nanoencapsulation of IFNα within nanoparticles of the mucoadhesive polysaccharide chitosan would improve the oral bioavailability of this drug. In this work, we produced IFNα-loaded chitosan nanoparticles by the ionotropic gelation method. Their hydrodynamic diameter, polydispersity index and concentration were characterized by dynamic light scattering and nanoparticle tracking analysis. After confirming their good cell compatibility in Caco-2 and WISH cells, the permeability of unmodified and poly(ethylene glycol) (PEG)-modified (PEGylated) nanoparticles was measured in monoculture (Caco-2) and co-culture (Caco-2/HT29-MTX) cell monolayers. Results indicated that the nanoparticles cross the intestinal epithelium mainly by the paracellular route. Finally, the study of the oral pharmacokinetics of nanoencapsulated IFNα in BalbC mice revealed two maxima and area-under-the-curve of 56.9 pg*h/mL.

Folate Receptor α-Modified Nanoparticles for Targeting of the Central Nervous System

Effective and timely delivery of therapeutic agents from the systemic circulation to the central nervous system (CNS) is often precluded by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). A new pathway of folate uptake mediated by folate receptor alpha (FRα, molecular weight of 28.29 kg mol^-1) occurring in various epithelial cells of the CNS (e.g., choroid plexus) was described. Aiming to investigate this mechanism for the delivery of nanomedicines to the CNS, in this work, we initially produced nanoparticles (NPs) made of a highly hydrophobic poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) block copolymer functionalized with an amine moiety in the edge of the PEG block by a simple nanoprecipitation method. Hydrophilic PEG blocks migrated to the NP surface during formation, exposing primary amine groups that were used to conjugate the targeting ligand, FRα. The size of the NPs was in the 58-98 nm range and standard deviation (S.D., a measure of the size population peak width) of 26-41 nm, as measured by dynamic light scattering (DLS). The FRα conjugation yield ranged between 50% and 75% (determined indirectly by the bicinchoninic acid protein assay). Pristine and FRα-modified NPs showed good compatibility with primary human choroid plexus epithelial cells (HCPEpiCs). The uptake of FRα-conjugated NPs by HCPEpiCs was qualitatively evaluated in vitro using inverted optical fluorescence and confocal microscopy. FRα-modified NPs were internalized by HCPEpiCs to a greater extent than the unmodified counterparts. Then, their permeability was characterized in standard and inverted HCPEpiC monolayers. In both cases, NPs surface modified with the FRα and complexed to folic acid (FA) showed significantly higher apparent permeability coefficient (P_app) values than the pristine ones. Finally, the biodistribution of unmodified and FRα-FA-modified NPs following intravenous (i.v.) administration was compared in ICR mice. Results indicated that conjugation of the FRα-FA complex to the NP surface promotes higher accumulation in the brain, highlighting the promise of FRα-FA-modified NPs to serve as a platform for the targeting of active molecules to the CNS from the systemic circulation.

Enhanced Thermostability and Anticancer Activity in Breast Cancer Cells of Laccase Immobilized on Pluronic-Stabilized Nanoparticles

Laccases are multi-copper oxidase enzymes having widespread applications in various biotechnological fields. However, low stability of free enzymes restricts their industrial use. Development of effective methods to preserve and even increase the enzymatic activity is critical to maximize their use, though this remains a challenge. In the present study we immobilized Trametes versicolor laccase on pH-responsive (and charge-switchable) Pluronic-stabilized silver nanoparticles (AgNPs^Trp). Our results demonstrate that colloidal stabilization of AgNPs^Trp with the amphiphilic copolymer Pluronic F127 enhances enzyme activity (AgNPsTrpF1 + Lac6) by changing the active site microenvironment, which is confirmed by circular dichroism (CD) and fluorescence spectroscopy. Detailed kinetic and thermodynamic studies reveal a facile strategy to improve the protein quality by lowering the activation energy and expanding the temperature window for substrate hydrolysis. The immobilized nanocomposite did not show any change in flow behavior which indirectly suggests that the enzyme stability is maintained, and the enzyme did not aggregate or unfold upon immobilization. Finally, assessing the anticancer efficacy of this nanocomposite in breast cancer MCF-7 cells shows the inhibition of cell proliferation through β-estradiol degradation and cells apoptosis. To understand the molecular mechanism involved in this process, semi qRT-PCR experiments were performed, which indicated significant decrease in the mRNA levels of anti-apoptotic genes, for example, BCL-2 and NF-kβ, and increase in the mRNA level of pro-apoptotic genes like p53 in treated cells, compared to control. Overall, this study offers a completely new strategy for tailoring nano-bio-interfaces with improved activity and stability of laccase.

Selective Accumulation of Galactomannan Amphiphilic Nanomaterials in Pediatric Solid Tumor Xenografts Correlates with GLUT1 Gene Expression

In this work, we designed, characterized, and investigated the performance of hydrolyzed galactomannan (hGM)-based amphiphilic nanoparticles for selective intratumoral accumulation in pediatric patient-derived sarcomas. To create a self-assembly amphiphilic copolymer, the side chain of hGM was hydrophobized with poly(methyl methacrylate) (PMMA) by utilizing a graft free radical polymerization reaction. Different hGM and MMA weight feeding ratios were used to adjust the critical aggregation concentration and the size and size distribution of the nanoparticles. The ability to actively target glucose transporter-1 (GLUT-1) was studied by fluorescence confocal microscopy and imaging flow cytometry in vitro on Rh30 (rhabdomyosarcoma) and patient-derived Ewing sarcoma (HSJD-ES-001) cell lines with different expression levels of GLUT-1. Results confirmed that the nanoparticles are internalized by ∼100% of the cells at 37 °C. Furthermore, we investigated the biodistribution of the nanoparticles in pediatric patient-derived models of two deadly musculoskeletal tumors, rhabdomyosarcoma and Ewing sarcoma. Outstandingly, the intratumoral accumulation of the nanoparticles correlated very well with the expression level of GLUT1 gene in each patient-derived tumor (P = 0.0141; Pearson's correlation test). Finally, we demonstrated the encapsulation capacity of these nanoparticles by loading 7.5% (w/w) of the hydrophobic first-generation tyrosine kinase inhibitor imatinib. These findings point out the potential of this new type of nanoparticle to target GLUT-1-expressing tumors and selectively deliver anticancer agents.

Enhanced Nanoencapsulation of Sepiapterin within PEG-PCL Nanoparticles by Complexation with Triacetyl-Beta Cyclodextrin

In this work, we aimed to improve the encapsulation efficiency of sepiapterin (SP), the natural precursor of the essential cofactor tetrahydrobiopterin (BH4) that displays mild water-solubility and a short biological half-life, within methoxy-poly(ethylene-glycol)-poly(epsilon-caprolactone)(mPEG-PCL) nanoparticles (NPs) by means of its complexation and hydrophobization with 2,3,6-triacetyl-β-cyclodextrin (TAβCD). For this, SP/TAβCD complexes were produced by spray-drying of SP/TAβCD binary solutions in ethanol using the Nano Spray Dryer B-90 HP. Dry powders were characterized by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and transmission and scanning electron microscopy (TEM and SEM, respectively) and compared to the pristine components and their physical mixtures (PMs). Next, SP was encapsulated within mPEG-PCL NPs by nano-precipitation of an SP/TAβCD complex/mPEG-PCL solution. In addition to the nano-encapsulation of a preformed complex within the polymeric NPs, we assessed an alternative encapsulation approach called drying with copolymer (DWC) in which pristine SP, TAβCD, and mPEG-PCL were co-dissolved in a mixture of acetone and methanol at the desired weight ratio, dried under vacuum, re-dissolved, and nano-precipitated in water. The dissolution-drying step was aimed to promote the formation of molecular hydrophobic interactions between SP, TAβCD, and the PCL blocks in the copolymer. SP-loaded mPEG-PCL NPs were characterized by dynamic light scattering (DLS) and SEM. NPs with a size of 74-75 nm and standard deviation (S.D., a measure of the peak width) of 21-22 nm were obtained when an SP:TAβCD (1:1 molar ratio) spray-dried complex was used for the nano-encapsulation and SEM analysis revealed the absence of free SP crystals. The encapsulation efficiency (%EE) and drug loading (%DL) were 85% and 2.6%, respectively, as opposed to the much lower values (14% and 0.6%, respectively) achieved with pristine SP. Moreover, the NPs sustained the SP release with relatively low burst effect of 20%. Overall, our results confirmed that spray-drying of SP/TAβCD solutions at the appropriate molar ratio leads to the hydrophobization of the relatively hydrophilic SP molecule, enabling its encapsulation within mPEG-PCL NPs and paves the way for the use of this strategy in the development of novel drug delivery systems of this vital biological precursor.

Mixed Mucoadhesive Amphiphilic Polymeric Nanoparticles Cross a Model of Nasal Septum Epithelium in Vitro

Intranasal administration of nano-drug-delivery systems emerged as an appealing strategy to surpass the blood-brain barrier and thus increase drug bioavailability in the central nervous system. However, a systematic study of the effect of the structural properties of the nanoparticles on the nose-to-brain transport is missing. In this work, we synthesized and characterized mixed amphiphilic polymeric nanoparticles combining two mucoadhesive graft copolymers, namely, chitosan- g-poly(methyl methacrylate) and poly(vinyl alcohol)- g-poly(methyl methacrylate), for the first time. Chitosan enables the physical stabilization of the nanoparticles by ionotropic cross-linking with tripolyphosphate and confers mucoadhesiveness, while poly(vinyl alcohol) is also mucoadhesive and, owing to its nonionic nature, it improves nanoparticle compatibility in nasal epithelial cells by reducing the surface charge of the nanoparticles. After a thorough characterization of the mixed nanoparticles by dynamic light scattering and nanoparticle tracking analysis, we investigated the cell uptake by fluorescence light and confocal microscopy and imaging flow cytometry. Mixed nanoparticles were readily internalized at 37 °C, while the uptake was inhibited almost completely at 4 °C, indicating the involvement of energy-dependent mechanisms. Finally, we assessed the nanoparticle permeability across liquid-liquid and air-liquid monolayers of a nasal septum epithelial cell line and studied the effect of nanoparticle concentration and temperature on the apparent permeability. Overall, our findings demonstrate that these novel amphiphilic nanoparticles cross this in vitro model of intranasal epithelium mainly by a passive (paracellular) pathway involving the opening of epithelial tight junctions.

Chitosan-graft-poly(methyl methacrylate) amphiphilic nanoparticles: Self-association and physicochemical characterization

In this work, we synthesized and characterized the self-assembly behavior of a chitosan-poly(methyl methacrylate) graft copolymer and the properties of the formed nanoparticles by static and dynamic light scattering, small-angle neutron scattering, and transmission electron microscopy. Overall, our results indicate that the hydrophobization of the chitosan side-chain with PMMA leads to a complex array of small unimolecular and/or small-aggregation number "building blocks" that further self-assemble into larger amphiphilic nanoparticles.

Tissue Compatibility of SN-38-Loaded Anticancer Nanofiber Matrices

Delivery of chemotherapy in the surgical bed has shown preclinical activity to control cancer progression upon subtotal resection of pediatric solid tumors, but whether this new treatment is safe for tumor-adjacent healthy tissues remains unknown. Here, Wistar rats are used to study the anatomic and functional impact of electrospun nanofiber matrices eluting SN-38-a potent chemotherapeutic agent-on several body sites where pediatric tumors such as neuroblastoma, Ewing sarcoma, and rhabdomyosarcoma arise. Blank and SN-38-loaded matrices embracing the femoral neurovascular bundle or in direct contact with abdominal viscera (liver, kidney, urinary bladder, intestine, and uterus) are placed. Foreign body tissue reaction to the implants is observed though no histologic damage in any tissue/organ. Skin healing is normal. Tissue reaction is similar for SN-38-loaded and blank matrices, with the exception of the hepatic capsule that is thicker for the former although within the limits consistent with mild foreign body reaction. Tissue and organ function is completely conserved after local treatments, as assessed by the rotarod test (forelimb function), hematologic tests (liver and renal function), and control of clinical signs. Overall, these findings support the clinical translation of SN-38-loaded nanofiber matrices to improve local control strategies of surgically resected tumors.

Nanoparticle-in-microparticle oral drug delivery system of a clinically relevant darunavir/ritonavir antiretroviral combination

Nanonizationhas been extensively investigated to increase theoral bioavailability of hydrophobicdrugsin general andantiretrovirals(ARVs)used inthe therapy of the human immunodeficiency virus (HIV) infection in particular. Weanticipatedthatin the caseofprotease inhibitors, a family of pH-dependent ARVsthatdisplay high aqueous solubility undertheacidconditionsof thestomach andextremely low solubilityunder the neutral ones ofthe small intestine, this strategy might failowing to an uncontrolled dissolution-re-precipitation process that will take place along the gastrointestinal tract.To tackle thisbiopharmaceutical challenge, in this work, wedesigned, produced and fully characterized a novelNanoparticle-in-MicroparticleDelivery System(NiMDS)comprised of pure nanoparticlesofthefirst-line protease inhibitor darunavir(DRV) and itsboosting agentritonavir (RIT) encapsulated within film-coated microparticles.For this, a clinically relevant combination of pure DRV and RIT nanoparticles wassynthesized by a sequential nanoprecipitation/solvent diffusion and evaporation method employing sodium alginateas viscosity stabilizer. Then, pure nanoparticles were encapsulated within calcium alginate/chitosanmicroparticlesthat were film-coated with a series ofpoly(methacrylate) copolymers with differential solubility in the gastrointestinal tract. This coating ensured full stability under gastric-like pH and sustained drug release under intestinal one. PharmacokineticstudiesconductedinalbinoSpragueDawleyratsshowed that DRV/RIT-loadedNiMDSs containing 17% w/w drug loading based on dry weight significantlyincreasedthe oral bioavailabilityof DRVby 2.3-foldwith respect to both theunprocessedandthenanonized DRV/RIT combinations that showed statistically similar performance. Moreover, they highlighted the limited advantage of only drugnanonizationto improve the oral pharmacokinetics of protease inhibitors and the potential of our novel delivery approach to improve the oral pharmacokinetics of nanonized poorly water-soluble drugs displaying pH-dependent solubility.

STATEMENT OF SIGNIFICANCE

Protease inhibitors (PIs) are gold-standard drugs in many ARV cocktails. Darunavir (DRV) is the latest approved PI and it is included in the 20th WHO Model List of Essential Medicines. PIs poorly-water soluble at intestinal pH and more soluble under gastric conditions. Drug nanonization represents one of the most common nanotechnology strategies to increase dissolution rate of hydrophobic drugs and thus, their oral bioavailability. For instance, pure drug nanosuspensions became the most clinically relevant nanoformulation. However, according to the physicochemical properties of PIs, nanonization does not appear as a very beneficial strategy due to the fast dissolution rate anticipated under the acid conditions of the stomach and their uncontrolled recrystallization and precipitation in the small intestine that might result in the formation of particles of unpredictable size and structure (e.g., crystallinity and polymorphism) and consequently, unknown dissolution rate and bioavailability. In this work, we developed a sequential nanoprecipitation method for the production of pure nanoparticles of DRV and its boosting agent ritonavir in a clinically relevant 8:1 wt ratio using alginate as viscosity stabilizer and used this nanosuspension to produce a novel kind of nanoparticle-in-microparticle delivery system that was fully characterized and the pharmacokinetics assessed in rats. The most significant points of the current manuscript are.

Novel poly(vinyl alcohol)-based amphiphilic nanogels by non-covalent boric acid crosslinking of polymeric micelles

In this work, we report a new type of poly(vinyl alcohol)-g-poly(N-isopropylacrylamide) (PVA-g-PNiPAAm) amphiphilic nanogel produced by the non-covalent crosslinking of PVA polyol domains in preformed polymeric micelles with boric acid. The nanomaterials showed sizes in the 100-250 nm range (DLS) and a spherical morphology (HR-SEM). We demonstrated that the size of the polymeric micelles could be fine-tuned by changing the concentration (and the aggregation pattern) of the polymeric amphiphile in water. Upon crosslinking, the polymeric micelles turned into physically stable amphiphilic nanogels that displayed both size and size distribution similar to the micellar precursor for up to two weeks, even under disfavored conditions of concentration and temperature that, in the case of non-crosslinked counterparts, resulted in quick disassembly. In addition, we show for the first time the feasibility of spray-drying technology to consolidate the 3D network formed between PVA and boric acid and to produce stable powders that can be reconstituted upon use at any desired concentration. Moreover, the formation of a borated surface conferred the nanogels with good mucoadhesiveness in vitro. Finally, these novel nanomaterials showed optimal cell compatibility in a model of the intestinal epithelium, the Caco2 cell line. Overall results demonstrate the unprecedented versatility of the proposed modular approach and opens completely new horizons in the application of polymeric micelles and other self-assembled polymeric nanomaterials in diagnostics and therapeutics.

Electrohydrodynamic atomization and spray-drying for the production of pure drug nanocrystals and co-crystals

In recent years, nanotechnology has offered attractive opportunities to overcome the (bio)pharmaceutical drawbacks of most drugs such as low aqueous solubility and bioavailability. Among the numerous methodologies that have been applied to improve drug performance, a special emphasis has been made on those that increase the dissolution rate and the saturation solubility by the reduction of the particle size of pure drugs to the nanoscale and the associated increase of the specific surface area. Different top-down and bottom-up methods have been implemented, each one with its own pros and cons. Over the last years, the latter that rely on the dissolution of the drug in a proper solvent and its crystallization or co-crystallization by precipitation in an anti-solvent or, conversely, by solvent evaporation have gained remarkable impulse owing to the ability to adjust features such as size, size distribution, morphology and to control the amorphous/crystalline nature of the product. In this framework, electrohydrodynamic atomization (also called electrospraying) and spray-drying excel due to their simplicity and potential scalability. Moreover, they do not necessarily require suspension stabilizers and dry products are often produced during the formation of the nanoparticles what ensures physicochemical stability for longer times than liquid products. This review overviews the potential of these two technologies for the production of pure drug nanocrystals and co-crystals and discusses the recent technological advances and challenges for their implementation in pharmaceutical research and development.

Permeability of Novel Chitosan-g-Poly(Methyl Methacrylate) Amphiphilic Nanoparticles in a Model of Small Intestine In Vitro

Engineering of drug nanocarriers combining fine-tuned mucoadhesive/mucopenetrating properties is currently being investigated to ensure more efficient mucosal drug delivery. Aiming to improve the transmucosal delivery of hydrophobic drugs, we designed a novel nanogel produced by the self-assembly of amphiphilic chitosan graft copolymers ionotropically crosslinked with sodium tripolyphosphate. In this work, we synthesized, for the first time, chitosan-g-poly(methyl methacrylate) nanoparticles thiolated by the conjugation of N-acetyl cysteine. First, we confirmed that both non-crosslinked and crosslinked nanoparticles in the 0.05⁻0.1% w/v concentration range display very good cell compatibility in two cell lines that are relevant to oral delivery, Caco-2 cells that mimic the intestinal epithelium and HT29-MTX cells that are a model of mucin-producing goblet cells. Then, we evaluated the effect of crosslinking, nanoparticle concentration, and thiolation on the permeability in vitro utilizing monolayers of (i) Caco-2 and (ii) Caco-2:HT29-MTX cells (9:1 cell number ratio). Results confirmed that the ability of the nanoparticles to cross Caco-2 monolayer was affected by the crosslinking. In addition, thiolated nanoparticles interact more strongly with mucin, resulting in a decrease of the apparent permeability coefficient (Papp) compared to the pristine nanoparticles. Moreover, for all the nanoparticles, higher concentration resulted in lower Papp, suggesting that the transport pathways can undergo saturation.

Protoporphyrin IX-modified chitosan-g-oligo(NiPAAm) polymeric micelles: from physical stabilization to permeability characterization in vitro

Two main hurdles persist towards the more extensive bench-to-bed side translation of non-parenteral polymeric micelles. The first pertains to their thermodynamically-driven disassembly under uncontrolled dilution conditions in the biological milieu and upon interaction with biomacromolecules (e.g., proteins). The second is related to the relatively poor understanding of the pathways by which polymeric micelles improve the bioavailability of the payload by mucosal routes (e.g., intestinal). In this work, a chitosan-g-oligo(N-isopropylacrylamide) (CS-g-oligo(NiPAAm)) copolymer was modified with non-cytotoxic amounts of protoporphyrin IX (PP), a planar molecule of amphiphilic character that undergoes self-aggregation in water by forming π-π stacked supramolecular structures, to induce micellization under disfavored conditions and to serve as a fluorescent tracer for the measurement of the micelle permeability across a model of the intestinal epithelium in vitro. Findings indicated that the conjugation of PP amounts as low as 2% w/w induced the formation of micelles at temperatures below the lower critical solution temperature of oligo(NiPAAm) (30-32 °C). Moreover, permeability studies conducted at both 4 °C and 37 °C strongly suggested that despite the relatively large size of the micelles (200-300 nm), they cross the epithelial monolayer mainly by a paracellular pathway due to the opening of tight junctions. Complementary uptake studies by flow cytometry indicated that no endocytosis, though due to passive or facilitated diffusion, some internalization takes place.

Composite films for vaginal delivery of tenofovir disoproxil fumarate and emtricitabine

Prevention of male-to-female HIV transmission remains a huge challenge and topical pre-exposure prophylaxis (PrEP) using microbicides may help overcoming the problem. In this work, different types of films containing the antiretroviral drugs tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) were developed. Formulations based in poly(vinyl alcohol) and pectin were produced as single- or double-layered films. Films containing TDF/FTC or TDF/FTC-loaded Eudragit® L 100 nanoparticles (NPs) obtained by nano spray-drying were tested for physicochemical, technological and biological properties relevant to microbicide development. All systems featured organoleptic and mechanical properties considered suitable for vaginal use and potentially favoring users' acceptability. Film design (single- or double-layered, and the incorporation or not of NPs) had a greater impact on disintegration time and drug release in a simulated vaginal fluid. Upon film disintegration, pH and osmolality of the fluid remained within values considered compatible with the vaginal environment. Double-layered films significantly reduced burst effect and the overall release of both drugs as compared to fast releasing, single-layered films. The effect on delaying drug release was most noticeable when TDF/FTC-loaded NPs were incorporated into double-layered films. This last design seems particularly advantageous for the development of a coitus-independent, on-demand microbicide product. Moreover, all film types were shown potentially safe when evaluated by the MTT metabolic activity and lactate dehydrogenase release assays using HeLa and CaSki cervical cell lines. Overall, results support that proposed films may be suitable for the vaginal delivery of TDF/FTC in the context of topical PrEP.

Development of a Drug Delivery System Based on Chitosan Nanoparticles for Oral Administration of Interferon-α

Despite the good clinical efficacy of interferon-alpha (IFNα) to treat some types of cancer and viral infections, this biological drug is underused given its severe adverse effects and high dosing parenteral regimens. Aiming to achieve a breakthrough in therapy with IFNα, this work reports for the first time on the design and full characterization of a novel nanomedicine of IFNα-2b-loaded chitosan nanoparticles (IFN-CT NPs) for oral delivery. IFN-CT NPs produced by ionotropic gelation, encapsulating approximately 100% of the drug, showed a size of 36 ± 8 nm, zeta potential of +30 mV (dynamic light scattering), and spherical morphology (transmission electron microscopy). The antiviral activity of IFN-CT NPs in vitro was comparable to that of commercial IFNα. Remarkably, both treatments stimulated the expression of IFN response genes to a similar extent in both noninfected and infected cells with Human Lymphotropic-T Virus type 1. Finally, oral administration of IFN-CT NPs (0.3 MIU) to CF1 mice showed detectable levels of IFNα in plasma after 1 h, whereas no IFNα was detected with a commercial formulation. These results are encouraging and open a new avenue for the administration of this biological drug in a minimally invasive, safer, and more patient-compliant way.