Cytotoxicity of Different Excipients on RPMI 2650 Human Nasal Epithelial Cells

Enhanced Stability and Solidification of Volatile Eugenol by Cyclodextrin-Metal Organic Framework for Nasal Powder Delivery

Eugenol (Eug) holds potential as a treatment for bacterial rhinosinusitis by nasal powder drug delivery. To stabilization and solidification of volatile Eug, herein, nasal inhalable γ-cyclodextrin metal-organic framework (γ-CD-MOF) was investigated as a carrier by gas-solid adsorption method. The results showed that the particle size of Eug loaded by γ-CD-MOF (Eug@γ-CD-MOF) distributed in the range of 10-150 μm well. In comparison to γ-CD and β-CD-MOF, γ-CD-MOF has higher thermal stability to Eug. And the intermolecular interactions between Eug and the carriers were verified by characterizations and molecular docking. Based on the bionic human nasal cavity model, Eug@γ-CD-MOF had a high deposition distribution (90.07 ± 1.58%). Compared with free Eug, the retention time Eug@γ-CD-MOF in the nasal cavity was prolonged from 5 min to 60 min. In addition, the cell viability showed that Eug@γ-CD-MOF (Eug content range 3.125-200 µg/mL) was non-cytotoxic. And the encapsulation of γ-CD-MOF could not reduce the bacteriostatic effect of Eug. Therefore, the biocompatible γ-CD-MOF could be a potential and valuable carrier for nasal drug delivery to realize solidification and nasal therapeutic effects of volatile oils.

Nasal delivery of encapsulated recombinant ACE2 as a prophylactic drug for SARS-CoV-2

Angiotensin-converting enzyme 2 (ACE2) is responsible for cell fusion with SARS-CoV viruses. ACE2 is contained in different areas of the human body, including the nasal cavity, which is considered the main entrance for different types of airborne viruses. We took advantage of the roles of ACE2 and the nasal cavity in SARS-CoV-2 replication and transmission to develop a nasal dry powder. Recombinant ACE2 (rhACE2), after a proper encapsulation achieved via spray freeze drying, shows a binding efficiency with spike proteins of SARS-CoV-2 higher than 77 % at quantities lower than 5 µg/ml. Once delivered to the nose, encapsulated rhACE2 led to viability and permeability of RPMI 2650 cells of at least 90.20 ± 0.67 % and 47.96 ± 4.46 %, respectively, for concentrations lower than 1 mg/ml. These results were validated using nasal dry powder containing rhACE2 to prevent or treat infections derived from SARS-CoV-2.

In vitro and in vivo applications of a universal and synthetic thermo-responsive drug delivery hydrogel platform

A synthetic and thermo-responsive polymer, poly(N-isopropylacrylamide)-co-(polylactide/2-hydroxy methacrylate)-co-(oligo (ethylene glycol)), is used to formulate a universal carrier platform for sustained drug release. The enabling carrier, denoted as TP, is prepared by dissolving the polymer in an aqueous solution at a relatively neutral pH. A wide range of therapeutic moieties can be incorporated without the need for the addition of surfactants, organic solvents, and other reagents to the carrier system. The resulting solution is flowable through fine gauge needle, allowing accurate administration of TP to the target site. After injection, TP carrier undergoes a coil to globe phase transition to form a hydrogel matrix at the site. The benign nature of the polymer carrier and its physical gelation process are essential to preserve the biological activity of the encapsulated compounds while the adhesive hydrogel nature of the matrix allows sustained elusion and controlled delivery of the incorporated therapeutics. The TP carrier system has been shown to be non-toxic and elicits a minimal inflammatory response in multiple in vitro studies. These findings suggest the suitability of TP as an enabling carrier of therapeutics for localized and sustained drug delivery. To confirm this hypothesis, the capabilities of TP to encapsulate and effectively deliver multiple therapeutics of different physicochemical characteristics was evaluated. Specifically, a broad range of compounds were tested, including ciprofloxacin HCl, tumor necrosis factor-alpha (TNF-α), transforming growth factor beta 1 (TGF-β1), and recombinant human bone morphogenetic protein 2 (BMP2). In vitro studies confirmed that TP carrier is able to control the release of the encapsulated drugs over an extended period of time and mitigate their burst release regardless of the compounds' physiochemical properties for the majority of the loaded therapeutics. Importantly, in vitro and in vivo animal studies showed that the released drugs from the TP hydrogel matrix remained potent and bioactive, confirming the high potential of the TP polymer system as an enabling carrier.

Cytotoxicity and Thermal Characterization Assessment of Excipients for the Development of Innovative Lyophilized Formulations for Oncological Applications

Freeze-drying, also known as lyophilization, significantly improves the storage, stability, shelf life, and clinical translation of biopharmaceuticals. On the downside, this process faces complex challenges, i.e., the presence of freezing and drying stresses for the active compounds, the uniformity and consistency of the final products, and the efficiency and safety of the reconstituted lyophilized formulations. All these requirements can be addressed by adding specific excipients that can protect and stabilize the active ingredient during lyophilization, assisting in the formation of solid structures without interfering with the biological and/or pharmaceutical action of the reconstituted products. However, these excipients, generally considered safe and inert, could play an active role in the formulation interacting with the biological cellular machinery and promoting toxicity. Any side effects should be carefully identified and characterized to better tune any treatments in terms of concentrations and administration times. In this work, various concentrations in the range of 1 to 100 mg/mL of cellobiose, lactose, sucrose, trehalose, isoleucine, glycine, methionine, dextran, mannitol, and (2-hydroxypropyl)-β-cyclodextrin were evaluated in terms of their ability to create uniform and solid lyophilized structures. The freeze-dried products were then reconstituted in the appropriate cell culture media to assess their in vitro cytotoxicity on both a healthy cell line (B-lymphocytes) and their tumoral lymphoid counterpart (Daudi). Results showed that at 10 mg/mL, all the excipients demonstrated suitable lyophilized solid structures and high tolerability by both cell lines, while dextran was the only excipient well-tolerated also up to 100 mg/mL. An interesting result was shown for methionine, which even at 10 mg/mL, selectively affected the viability of the cancerous cell line only, opening future perspectives for antitumoral applications.

Engineered nasal dry powder for the encapsulation of bioactive compounds

In this review, we present the potential of nasal dry powders to deliver stable bioactive compounds and their manufacture using spray-drying (SD) techniques to achieve encapsulation. We also review currently approved and experimental excipients used for powder manufacturing for specific target drugs. Polymers, sugars, and amino acids are recommended for specific actions, such as mucoadhesive interactions, to increase residence time on the nasal mucosa; for example, high-molecular weight polymers, such as hydroxypropyl methylcellulose, or mannitol, which protect the bioactive compounds, increase their stability, and enhance drug absorption in the nasal mucosa; and leucine, which promotes particle formation and improves aerosol performance. Teaser: XXXX.

Versatile Nasal Application of Cyclodextrins: Excipients and/or Actives?

Cyclodextrins (CDs) are oligosaccharides widely used in the pharmaceutical field. In this review, a detailed examination of the literature of the last two decades has been made to understand the role of CDs in nasal drug delivery systems. In nasal formulations, CDs are used as pharmaceutical excipients, as solubilizers and absorption promoters, and as active ingredients due to their several biological activities (antiviral, antiparasitic, anti-atherosclerotic, and neuroprotective). The use of CDs in nasal formulations allowed obtaining versatile drug delivery systems intended for local and systemic effects, as well as for nose-to-brain transport of drugs. In vitro and in vivo models currently employed are suitable to analyze the effects of CDs in nasal formulations. Therefore, CDs are versatile pharmaceutical materials, and due to the continual synthesis of new CDs derivatives, the research on the new nasal applications is an interesting field evolving in the coming years, to which Italian research will still contribute.

Investigation of Cytotoxicity and Cell Uptake of Cationic Beta-Cyclodextrins as Valid Tools in Nasal Delivery

Cyclodextrin polymers have high applicability in pharmaceutical formulations due to better biocompatibility, solubility enhancement, loading capacity and controlled drug release than their parent, cyclodextrins. The cytotoxicity and cell uptake of new cationic beta-cyclodextrin monomers and polymers were evaluated as suitable materials for nasal formulations and their protective effects on cells exposed to hydrogen peroxide were studied. PC12 and CACO-2 cells were selected as the neuronal- and epithelial-type cells, respectively, to mimic the structure of respiratory and olfactory epithelia of the nasal cavity. All cationic beta-cyclodextrin polymers tested showed dose- and time-dependent toxicity; nevertheless, at 5 µM concentration and 60 min of exposure, the quaternary-ammonium-beta-cyclodextrin soluble polymer could be recognized as nontoxic. Based on these results, a fluorescently labelled quaternary-ammonium-beta-cyclodextrin monomer and polymer were selected for uptake studies in CACO-2 cells. The monomeric and polymeric beta-cyclodextrins were internalized in the cytoplasm of CACO-2 cells; the cationic monomer showed higher permeability than the hydroxypropyl-beta-cyclodextrin, employed as comparison. Therefore, these cationic beta-cyclodextrins showed potential as excipients able to improve the nasal absorption of drugs. Furthermore, amino-beta-cyclodextrin and beta-cyclodextrin soluble polymers were able to reduce oxidative damage in PC12 and CACO-2 cells and thus could be studied as bioactive carriers or potential drugs for cell protection against oxidative stress.

Piribedil loaded thermo-responsive nasal in situ gelling system for enhanced delivery to the brain: formulation optimization, physical characterization, and in vitro and in vivo evaluation

Methyl cellulose (MC) based nasal in situ gels were developed to enhance the brain delivery of piribedil (PBD), an anti-Parkinson's drug. Different grades of MC and several solutes (NaCl, KCl, Na.Citrate, STPP, PEG-6000, sucrose, etc.) were screened to formulate thermo-responsive nasal in situ gelling systems. Formulations were evaluated for their sol-gel transition temperature and time, rheological behaviour, in vitro drug release, mucociliary clearance (MCC), ex vivo nasal toxicity, and in vivo brain availability studies in Wistar rats. Intranasal (i.n.) administration was carried out using a cannula-microtip setup to deliver PBD at the olfactory region of the nose. The concentration and viscosity grade of MC and also the concentration and type of solute used were found to affect the rheological behaviour of the formulations. Among the solutes tested, NaCl was found to be effective for formulating MC in situ gels. The developed in situ gels significantly delayed the MCC of PBD from the site of administration when compared with conventional suspension (p < 0.05). Further, formulations with higher gel strength showed lower in vitro drug release rate and longer intranasal residence (delayed MCC) (p < 0.05). The absolute brain availability (brain AUC_0-t) of PBD increased to 35.92% with i.n. delivery when compared to 4.71% with oral administration. Overall, it can be concluded that intranasal delivery of PBD is advantageous when compared to the currently practiced oral therapy. Graphical abstract.

Formulation Strategies to Improve Nose-to-Brain Delivery of Donepezil

Donepezil (DPZ) is widely used in the treatment of Alzheimer's disease in tablet form for oral administration. The pharmacological efficacy of this drug can be enhanced by the use of intranasal administration because this route makes bypassing the blood⁻brain barrier (BBB) possible. The aim of this study was to develop a nanoemulsion (NE) as well as a nanoemulsion with a combination of bioadhesion and penetration enhancing properties (PNE) in order to facilitate the transport of DPZ from nose-to-brain. Composition of NE was established using three pseudo-ternary diagrams and PNE was developed by incorporating Pluronic F-127 to the aqueous phase. Parameters such as physical properties, stability, in vitro release profile, and ex vivo permeation were determined for both formulations. The tolerability was evaluated by in vitro and in vivo models. DPZ-NE and DPZ-PNE were transparent, monophasic, homogeneous, and physically stable with droplets of nanometric size and spherical shape. DPZ-NE showed Newtonian behavior whereas a shear thinning (pseudoplastic) behavior was observed for DPZ-PNE. The release profile of both formulations followed a hyperbolic kinetic. The permeation and prediction parameters were significantly higher for DPZ-PNE, suggesting the use of polymers to be an effective strategy to improve the bioadhesion and penetration of the drug through nasal mucosa, which consequently increase its bioavailability.

In vitro characterization of physico-chemical properties, cytotoxicity, bioactivity of urea-crosslinked hyaluronic acid and sodium ascorbyl phosphate nasal powder formulation

An innovative lyophilized dry powder formulation consisting of urea-crosslinked hyaluronic acid (HA-CL) and sodium ascorbyl phosphate (SAP) - LYO HA-CL - SAP- was prepared and characterized in vitro for physico-chemical and biological properties. The aim was to understand if LYO HA-CL - SAP could be used as adjuvant treatment for nasal inflammatory diseases. LYO HA-CL - SAP was suitable for nasal delivery and showed to be not toxic on human nasal septum carcinoma-derived cells (RPMI 2650 cells) at the investigated concentrations. It displayed porous, polygonal particles with unimodal, narrow size distribution, mean geometric diameter of 328.3 ± 27.5 µm, that is appropriate for nasal deposition with no respirable fraction and 88.7% of particles with aerodynamic diameter >14.1 µm. Additionally, the formulation showed wound healing ability on RPMI 2650 cells, and reduced interleukin-8 (IL-8) level in primary nasal epithelial cells pre-induced with lipopolysaccharide (LPS). Transport study across RPMI 2650 cells showed that HA-CL could act not only as carrier for SAP and active ingredient itself, but potentially also as mucoadhesive agent. In conclusion, these results suggest that HA-CL and SAP had anti-inflammatory activity and acted in combination to accelerate wound healing. Therefore, LYO HA-CL - SAP could be a potential adjuvant in nasal anti-inflammatory formulations.

Aerodynamic properties and in silico deposition of meloxicam potassium incorporated in a carrier-free DPI pulmonary system

Dry powder inhalers (DPIs) have been among the fastest developing inhaler forms in the past decades. Researches are focusing on the formulation of carrier-free powders to obtain a higher deep-lung deposition and hereby to increase the effectiveness of the medicine. The aim of our study was to prepare a carrier-free dry powder formulation of meloxicam potassium (MP), a novel salt form of meloxicam, using a one-step co-spray drying technology. Different types of excipients were used to modify the crystal structure and to increase aerosolization efficacy. Micrometric properties and the crystal structure were characterized. Aerodynamic properties were tested in vitro using an Andersen Cascade Impactor. A new in silico Stochastic Lung Model was also applied to quantify the amount of particles deposited at the target area. The results have shown that formulated DPI samples are fulfilling the requirements of effective pulmonary drug delivery: they include spherical particles with low density and 1-5μm size distribution. The in silico deposition results correspond with the in vitro measurements and demonstrate that the engineered microcomposites reach a high lung deposition. MP offers a novel opportunity for a well-controlled DPI formulation prepared by a solution-based co-spray drying method.

Application of RPMI 2650 as a cell model to evaluate solid formulations for intranasal delivery of drugs

During the development of intranasal drug delivery systems for local/systemic effect or brain targeting, it is necessary to assess its cytotoxicity and drug transport through nasal epithelium. In order to avoid animal experiments or the use of excised tissues, in vitro cell models, such as RPMI 2650 cells, are being preferred during recent years. Nevertheless, the deposition of solid formulations into nasal cell layers with further transepithelial transport rate of drugs has been poorly studied or reported. Thus, the purpose of this work is to further investigate RPMI 2650 cell line as an effective alternative to animal tissues for solid drug-loaded formulations cytotoxicity and drug permeation studies in order to become an option as a tool for drug discovery. Furthermore, we wanted to determine the extent to which the administration of drugs in particulate forms would differ in relation to the permeability of the same compounds applied as solutions. RPMI 2650 cells were cultured in submersed or at air-liquid interface conditions and characterized regarding transepithelial electrical resistance (TEER) and production of mucus. Pure ketoprofen (used as model compound) and five formulations loaded with same drug, namely solid lipid particles (Gelucire 43/01™), structured lipid particles (Gelucire 43/01™:Glyceryl monooleate) and aerogel microparticles (Alginate, Alginate:Pectin, Alginate:Carrageenan), were evaluated with RPMI 2650 model in terms of cytotoxicity and permeability of drug (applied as solution, dispersion or powder+buffer). RPMI 2650 cells were capable to grow in monolayer and multilayer, showing the same permeability as excised human nasal mucosa for sodium fluorescein (paracellular marker), with analogous TEER values and production of mucus, as referred by other authors. None of the powders showed cytotoxicity when applied to RPMI 2650 cells. Regarding permeation of drug through cell layers, not only the form of application of powders but also their physical and chemical properties affected the final permeation of active pharmaceutical ingredient. Aerogel microparticles administered directly to the cell layer (powder+buffer) exhibited the highest permeation-enhancing effect compared to the pure drug, which can be attributed to the mucoadhesive properties of the materials composing the carriers, proving to be an attractive formulation for nasal drug delivery. According to these results, RPMI 2650 showed to be a promising alternative to ex vivo or in vivo nasal models for cytotoxicity and evaluation of drug permeability of nasal drug-loaded formulations.