Systematic review and QSPR analysis of chemical penetration through the nail to inform onychomycosis candidate selection.

Recalcitrant nail plate infections can be life-long problems because localizing antifungal agents into infected tissues is problematic. In this systematic review, guided by the SPIDER method, we extracted chemical nail permeation data for 38 compounds from 16 articles, and analyzed the data using quantitative structure-property relationships (QSPRs). Our analysis demonstrated that low-molecular weight was essential for effective nail penetration, with <120 g/mol being preferred. Interestingly, chemical polarity had little effect on nail penetration; therefore, small polar molecules, which effectively penetrate the nail, but not the skin, should be set as the most desirable target chemical property in new post-screen onychomycosis candidate selections.

Laser-cutting: A novel alternative approach for point-of-care manufacturing of bespoke tablets.

A novel subtractive manufacturing method to produce bespoke tablets with immediate and extended drug release is presented. This is the first report on applying fusion laser cutting to produce bespoke furosemide solid dosage forms based on pharmaceutical-grade polymeric carriers. Cylindric tablets of different sizes were produced by controlling the two-dimensional design of circles of the corresponding diameter. Immediate and extended drug release patterns were achieved by modifying the composition of the polymeric matrix. Thermal analysis and XRD indicated that furosemide was present in an amorphous form. The laser-cut tablets demonstrated no significant drug degradation (<2%) nor the formation of impurities were identified. Multi-linear regression was used to quantify the influences of laser-cutting process parameters (laser energy levels, scan speeds, and the number of laser applications) on the depth of the laser cut. The utility of this approach was exemplified by manufacturing tablets of accurate doses of furosemide. Unlike additive or formative manufacturing, the reported approach of subtractive manufacturing avoids the modification of the structure, e.g., the physical form of the drug or matrix density of the tablet during the production process. Hence, fusion laser cutting is less likely to modify critical quality attributes such as release patterns or drug contents. In a point-of-care manufacturing scenario, laser cutting offers a significant advantage of simplifying quality control and a real-time release of laser-cut products such as solid dosage forms and implants.

In-Silico Modelling of Transdermal Delivery of Macromolecule Drugs Assisted by a Skin Stretching Hypobaric Device.

OBJECTIVES: To develop a simulation model to explore the interplay between mechanical stretch and diffusion of large molecules into the skin under locally applied hypobaric pressure, a novel penetration enhancement method. METHODS: Finite element method was used to model the skin mechanical deformation and molecular diffusion processes, with validation against in-vitro transdermal permeation experiments. Simulations and experimental data were used together to investigate the transdermal permeation of large molecules under local hypobaric pressure. RESULTS: Mechanical simulations resulted in skin stretching and thinning (20%-26% hair follicle diameter increase, and 21%-27% skin thickness reduction). Concentration of dextrans in the stratum corneum was below detection limit with and without hypobaric pressure. Concentrations in viable epidermis and dermis were not affected by hypobaric pressure (approximately 2 µg [Formula: see text] cm-2). Permeation into the receptor fluid was substantially enhanced from below the detection limit at atmospheric pressure to up to 6 µg [Formula: see text] cm-2 under hypobaric pressure. The in-silico simulations compared satisfactorily with the experimental results at atmospheric conditions. Under hypobaric pressure, satisfactory comparison was attained when the diffusion coefficients of dextrans in the skin layers were increased from [Formula: see text] 10 µm2 [Formula: see text] s-1 to between 200-500 µm2 [Formula: see text] s-1. CONCLUSIONS: Application of hypobaric pressure induces skin mechanical stretching and enlarges the hair follicle. This enlargement alone cannot satisfactorily explain the increased transdermal permeation into the receptor fluid under hypobaric pressure. The results from the in-silico simulations suggest that the application of hypobaric pressure increases diffusion in the skin, which leads to improved overall transdermal permeation.

Needleless administration of advanced therapies into the skin via the appendages using a hypobaric patch.

Advanced therapies are commonly administered via injection even when they act within the skin tissue, and this increases the chances of off-target effects. Here we report the use of a skin patch containing a hypobaric chamber that induces skin dome formation to enable needleless delivery of advanced therapies directly into porcine, rat, and mouse skin. Finite element method modeling showed that the hypobaric chamber in the patch opened the skin appendages by 32%, thinned the skin, and compressed the appendage wall epithelia. These changes allowed direct delivery of an H1N1 vaccine antigen and a diclofenac nanotherapeutic into the skin. Fluorescence imaging and infrared mapping of the skin showed needleless delivery via the appendages. The in vivo utility of the patch was demonstrated by a superior immunoglobulin G response to the vaccine antigen in mice compared to intramuscular injection and a 70% reduction in rat paw swelling in vivo over 5 h with diclofenac without skin histology changes.

Investigating how amine structure influences drug-amine ion-pair formation and uptake via the polyamine transporter in A549 lung cells.

Transiently associating amines with therapeutic agents through the formation of ion-pairs has been established both in vitro and in vivo as an effective means to systemically direct drug delivery to the lung via the polyamine transport system (PTS). However, there remains a need to better understand the structural traits required for effective PTS uptake of drug ion-pairs. This study aimed to use a structurally related series of amine counterions to investigate how they influenced the stability of theophylline ion-pairs and their active uptake in A549 cells. Using ethylamine (mono-amine), ethylenediamine (di-amine), spermidine (tri-amine) and spermine (tetra-amine) as counterions the ion-pair affinity was shown to increase as the number of protonated amine groups in the counterion structure increased. The mono and diamines generated a single hydrogen bond and the weakest ion-pair affinities (pKFTIR: 1.32 ± 0.04 and 1.43 ± 0.02) whereas the polyamines produced two hydrogen bonds and thus the strongest ion-pair affinities (pKFTIR: 1.93 ± 0.05 and 1.96 ± 0.04). In A549 cells depleted of endogenous polyamines using α-difluoromethylornithine (DFMO), the spermine-theophylline uptake was significantly increased (p < 0.05) compared to non-amine depleted cells and this evidenced the active PTS sequestering of the ion-pair. The mono-amine and di-amine failed to enhance theophylline uptake in these A549 cells, but the tri-amine and tetra-amine both almost doubled the theophylline uptake into the cells when compared to the uptake of free drug. As the data indicated that polyamines with at least 3 amines were required to form ion-pairs that could enhance A549 cell uptake, it suggested that at least two amines were required to physically stabilise the ion-pair and one to interact with the PTS.

Nanomaterials fusing with the skin: Alpha-tocopherol phosphate delivery into the viable epidermis to protect against ultraviolet radiation damage.

Vitamin E (alpha tocopherol, α-T) is an important skin antioxidant, but its penetration into the viable epidermis, where it acts, is very limited. This study investigated if phosphorylating α-tocopherol (α-TP) to form a provitamin, improved its interactions with skin, its passage into the tissue, and thus its ability to protect the skin from ultraviolet radiation (UVR) damage. At pH 7.4, when the α-TPO4-1 microspecies predominated in solution, dynamic light scattering measurements showed that α-TP formed nanoaggregates with a median hydrodynamic diameter of 9 nm (Critical aggregation constant, CAC, - 4.2 mM). At 9.0 when the α-TPO4-2 microspecies predominated there was no aggregation. The passage of α-TP nanoaggregates through regenerated cellulose membranes was significantly slower than the α-TP monomers (at pH 9) suggesting that aggregation slowed diffusion. However, a lotion formulation containing the nanoaggregates delivered more α-TP into the skin compared to the formulation containing the monomers. In addition, the nanosized α-TP aggregates delivered 8-fold more active into the stratum corneum (SC) (252.2 µg/cm2 vs 29.5 µg/cm2) and 4 fold more active into the epidermis (85.1 µg/cm2 vs 19 µg/cm2, respectively, p < 0.05) compared to α-T. Langmuir subphase injection studies at pH 7.4 (surface pressure 10 mN m-1) showed that the α-TP nanoaggregates more readily fused with the SC compared to the monomers and the membrane compression studies demonstrated that α-TP fluidised the SC lipids. Together the fusion with the SC and its fluidisation were proposed as the causes of the better α-TP penetration into the skin, which enhanced potential of α-TP to protect from UVR-induced skin damage compared to α-T.

Quality and use of unlicensed vitamin D preparations in primary care in England: Retrospective review of national prescription data and laboratory analysis.

AIM: To evaluate the type (licensed vs unlicensed) and cost of preparations used to fulfil vitamin D prescriptions in England over time, and to compare measured vitamin D content of selected vitamin D preparations against labelled claim. METHODS: Retrospective analysis of vitamin D prescription data in primary care in England (2008-2018). Laboratory analysis of 13 selected vitamin D preparations. RESULTS: Alongside a rise in the number of oral licensed colecalciferol preparations from 0 to 27 between 2012 and 2018, the proportion of vitamin D prescriptions in which licensed vitamin D preparations were supplied increased from 11.8 to 54.2%. However, the use of unlicensed food supplements (dose strength 400-50 000 IU) remained high, accounting for 39.7% of vitamin D prescriptions in 2018. The two licensed preparations showed mean (±SD) vitamin D content of 90.9 ± 0.7% and 90.5 ± 3.9% of the labelled claimed amount, meeting the British Pharmacopeia specification for licensed medicines (90-125% of labelled claim). The 11 food supplements showed vitamin D content ranging from 41.2 ± 10.6% to 165.3 ± 17.8% of the labelled claim, with eight of the preparations failing to comply with the food supplement specification (80-150% of labelled claim). CONCLUSIONS: Despite the increasing availability of quality assured licensed preparations, food supplements continued to be used interchangeably with licensed preparations to fulfil vitamin D prescriptions. Food supplements, manufactured under less stringent quality standards, showed wide variations between measured and declared vitamin D content, which could lead to the risk of under- and over-dosing.

A Cyclodextrin-Stabilized Spermine-Tagged Drug Triplex that Targets Theophylline to the Lungs Selectively in Respiratory Emergency.

Ion-pairing a lifesaving drug such as theophylline with a targeting moiety could have a significant impact on medical emergencies such as status asthmaticus or COVID-19 induced pneumomediastinum. However, to achieve rapid drug targeting in vivo the ion-pair must be protected against breakdown before the entry into the target tissue. This study aims to investigate if inserting theophylline, when ion-paired to the polyamine transporter substrate spermine, into a cyclodextrin (CD), to form a triplex, could direct the bronchodilator to the lungs selectively after intravenous administration. NMR demonstrates that upon the formation of the triplex spermine protruded from the CD cavity and this results in energy-dependent uptake in A549 cells (1.8-fold enhancement), which persists for more than 20 min. In vivo, the triplex produces a 2.4-fold and 2.2-fold increase in theophylline in the lungs 20 min after injection in rats and mice, respectively (p < 0.05). The lung targeting is selective with no increase in uptake into the brain or the heart where the side-effects of theophylline are treatment-limiting. Selectively doubling the concentration of theophylline in the lungs could improve the benefit-risk ratio of this narrow therapeutic index medicine, which continues to be important in critical care.

Using Polar Ion-Pairs to Control Drug Delivery to the Airways of the Lungs.

The rapid absorptive clearance of drugs delivered to the airways of the lungs means that many inhaled medicines have a short duration of action. The aim of this study was to investigate whether forming polar ion-pairs can modify drug absorption to slow down clearance from the airways. Salbutamol was used as a model drug and was formulated as ion-pairs in an aqueous solution with three negatively charged hydrophilic counterions: sulfate (molecular weight (MW) 142), gluconate (MW 218), and phytate (MW 736) (association constants of 1.57, 2.27, and 4.15, respectively) and one negatively charged hydrophobic counterion, octanoate (MW 166) (association constant, 2.56). All of the counterions were well tolerated by Calu-3 human bronchial epithelial cells when screened for toxicity in vitro using conditions that in silico simulations suggested maintain >80% drug-counterion association. The transport of salbutamol ion-pairs with higher polar surface area (PSA), i.e., the sulfate (PSA 52%), gluconate (PSA 50%), and phytate (PSA 79%) ion-pairs, was significantly lower compared to that of the drug alone (PSA 30%, p < 0.05). In contrast, the octanoate ion-pair (PSA 23%) did not significantly alter the salbutamol transport. The transport data for the gluconate ion-pair suggested that the pulmonary absorption half-life of the ion-paired drug would be double that of salbutamol base, and this illustrates the promise of increasing drug polarity using noncovalent complexation as an approach to control drug delivery to the airways of the lungs.

Targeting macrophages and their recruitment in the oral cavity using swellable (+) alpha tocopheryl phosphate nanostructures.

The phosphorylation of (+) alpha tocopherol produces adhesive nanostructures that interact with oral biofilms to restrict their growth. The aim of this work was to understand if these adhesive (+) alpha tocopheryl phosphate (α-TP) nanostructures could also control macrophage responses to the presence of oral bacteria. The (+) α-TP planar bilayer fragments (175 nm ±â€¯21 nm) formed in a Trizma®/ethanol vehicle swelled when exposed to the cell lines (maximum stabilized size = 29 µm). The swelled (+) α-TP aggregates showed selective toxicity towards THP-1 macrophages (LD50 = 304 µM) compared to human gingival fibroblasts (HGF-1 cells; LD50 > 5 mM), and they inhibited heat killed bacteria stimulated MCP-1 production in both macrophages (control 57.3 ±â€¯18.1 pg/mL vs (+) α-TP 6.5 ±â€¯3.2 pg/mL) and HGF-1 cells (control 673.5 ±â€¯133 pg/mL vs (+) α-TP - 463.9 ±â€¯68.9 pg/mL).

Mucus penetrating properties of soft, distensible lipid nanocapsules.

Designing nanomaterials to release their drug pay-load upon exposure to an exogenous trigger can help to direct drug delivery, but how the triggered release, which often modifies the nanomaterial properties, influences the biological fate of these systems is currently unknown. The aim of this study was to investigate how the triggered drug release from PEG coated, soft, 50 nm distensible lipid nanocapsules (LNC) influenced their diffusion across a mucus barrier. The translocation speed of the non-triggered LNC across a 35 µm thick purified gastric mucin (PGM) barrier was 3 times faster (30.08 ±â€¯2.49 × 10-10 cm2 s-1) compared to equivalent-sized negatively charged polystyrene particles (9.87 ±â€¯0.61 × 10-10 cm2 s-1, p < 0.05). In cystic fibrosis mucus (CFM), harvested from patient primary cells, the non-triggered LNC translocation speed was similar to the PGM, but the polystyrene particle diffusion was so slow it could not be measured. The trigger induced LNC distension process had no effect on the particle diffusion rate in both PGM and CFM (p > 0.05) in a static mucus barrier, but when shear was applied to the barrier the distended LNCs diffused more slowly (3.97 ±â€¯1.38 × 10-8 cm2 s-1, p < 0.05) compared to the non-distended materials (4.94 ±â€¯0.04 × 10-8 cm2 s-1). This data suggested the rapid mucus penetration of the distended LNCs, despite their increased size, was a consequence of their capacity to take a less tortuous path through the barrier, i.e., they experienced less steric hinderance, compared to the non-distended LNC.

Diminishing biofilm resistance to antimicrobial nanomaterials through electrolyte screening of electrostatic interactions.

The extracellular polymer substances (EPS) generated by biofilms confers resistance to antimicrobial agents through electrostatic and steric interactions that hinder molecular diffusion. This resistance mechanism is particularly evident for antibacterial nanomaterials, which inherently diffuse more slowly compared to small organic antibacterial agents. The aim of this study was to determine if a biofilm's resistance to antibacterial nanomaterial diffusion could be diminished using electrolytes to screen the EPS's electrostatic interactions. Anionic (+) alpha-tocopherol phosphate (α-TP) liposomes were used as the antimicrobial nanomaterials in the study. They self-assembled into 700 nm sized structures with a zeta potential of -20 mV that were capable of killing oral bacteria (S. oralis growth inhibition time of 3.34 ± 0.52 h). In a phosphate (-ve) buffer the -ve α-TP liposomes did not penetrate multispecies oral biofilms, but in a Tris (hydroxymethyl)aminomethane (+ve) buffer they did (depth - 12.4 ± 3.6 µm). The Tris did not modify the surface charge of the α-TP nanomaterials, rather it facilitated the α-TP-biofilm interactions through electrolyte screening (Langmuir modelled surface pressure increase of 2.7 ± 1.8 mN/ m). This data indicated that EPS resistance was mediated through charge repulsion and that this effect could be diminished through the co-administration of cationic electrolytes.

Effective silencing of ENaC by siRNA delivered with epithelial-targeted nanocomplexes in human cystic fibrosis cells and in mouse lung.

INTRODUCTION: Loss of the cystic fibrosis transmembrane conductance regulator in cystic fibrosis (CF) leads to hyperabsorption of sodium and fluid from the airway due to upregulation of the epithelial sodium channel (ENaC). Thickened mucus and depleted airway surface liquid (ASL) then lead to impaired mucociliary clearance. ENaC regulation is thus a promising target for CF therapy. Our aim was to develop siRNA nanocomplexes that mediate effective silencing of airway epithelial ENaC in vitro and in vivo with functional correction of epithelial ion and fluid transport. METHODS: We investigated translocation of nanocomplexes through mucus and their transfection efficiency in primary CF epithelial cells grown at air-liquid interface (ALI).Short interfering RNA (SiRNA)-mediated silencing was examined by quantitative RT-PCR and western analysis of ENaC. Transepithelial potential (Vt), short circuit current (Isc), ASL depth and ciliary beat frequency (CBF) were measured for functional analysis. Inflammation was analysed by histological analysis of normal mouse lung tissue sections. RESULTS: Nanocomplexes translocated more rapidly than siRNA alone through mucus. Transfections of primary CF epithelial cells with nanocomplexes targeting αENaC siRNA, reduced αENaC and ßENaC mRNA by 30%. Transfections reduced Vt, the amiloride-sensitive Isc and mucus protein concentration while increasing ASL depth and CBF to normal levels. A single dose of siRNA in mouse lung silenced ENaC by approximately 30%, which persisted for at least 7 days. Three doses of siRNA increased silencing to approximately 50%. CONCLUSION: Nanoparticle-mediated delivery of ENaCsiRNA to ALI cultures corrected aspects of the mucociliary defect in human CF cells and offers effective delivery and silencing in vivo.

Soft, adhesive (+) alpha tocopherol phosphate planar bilayers that control oral biofilm growth through a substantive antimicrobial effect.

'Soft' nanomaterials have the potential to produce substantive antibiofilm effects. The aim of this study was to understand the oral antimicrobial activity of soft nanomaterials generated from alpha-tocopherol (α-T) and alpha-tocopherol phosphate (α-TP). (+) α-TP formed planar bilayer islands (175 ± 21 nm, -14.9 ± 3.5 mV) in a Trizma® buffer, whereas (+) α-T formed spherical liposomes (563 ± 1 nm, -10.5 ± 0.2 mV). The (+) α-TP bilayers displayed superior Streptococcus oralis biofilm growth retardation, a more substantive action, generated a superior adsorption to hydroxyapatite and showed an enhanced inhibition of multi-species bacterial saliva biofilm growth (38 ± 7µm vs 58 ± 18 µm, P ˂ 0.05) compared to (+) α-T. Atomic force microscopy data indicated that the ability of the 'soft' α-TP nanomaterials to transition into planar bilayer structures upon contact with interfaces facilitated their adhesive properties and substantive antimicrobial effects.

Ion-Pairing with Spermine Targets Theophylline To the Lungs via the Polyamine Transport System.

Certain xenobiotics, such as paraquat, are sequestered into the lungs from the systemic circulation by the polyamine transporter system (PTS). The aim of this study was to investigate whether ion-pairing a drug (theophylline) with a PTS substrate (spermine) provides a means of using this active transport mechanism to target drug delivery to the lungs. Fourier transform infrared spectroscopy showed that two of the amine groups of spermine interact with C-N7 and C6═O of theophylline, leaving two free amines to interact with the PTS. In A549 cells, which possess a functional PTS (spermidine Km and Vmax, 0.6 ± 0.3 µM and 1.8 ± 0.3 pmol·min-1 per 105 cells, respectively), uptake of the theophylline-spermine ion-pair was increased 1.8-fold compared to free theophylline at 37 °C, but not at 4 °C. In an isolated perfused rat lung model (IPL) a 3.6-fold increase in lung theophylline concentration was observed after vascular administration of the ion-pair compared to free theophylline. Theophylline was cleared from the IPL with similar kinetics irrespective of whether it was delivered as the free drug or an ion-pair, although lung levels remained elevated after washout following delivery as an ion-pair. In vitro simulation of the theophylline-spermine break down demonstrated that a drop in pH from 9.6 to 7.4, such as that undergone by the ion-pair in biological matrices, induces rapid and almost complete dissociation of the ion-paired species. However, infusion of the ion-pair formulations via the vasculature provides almost immediate delivery to the pulmonary capillary bed permitting PTS-mediated active sequestering of ion-paired theophylline into the lungs.

The value of virtual conferencing for ecology and conservation.

The objectives of conservation science and dissemination of its research create a paradox: Conservation is about preserving the environment, yet scientists spread this message at conferences with heavy carbon footprints. Ecology and conservation science depend on global knowledge exchange-getting the best science to the places it is most needed. However, conference attendance from developed countries typically outweighs that from developing countries that are biodiversity and conservation hotspots. If any branch of science should be trying to maximize participation while minimizing carbon emissions, it is conservation. Virtual conferencing is common in other disciplines, such as education and humanities, but it is surprisingly underused in ecology and conservation. Adopting virtual conferencing entails a number of challenges, including logistics and unified acceptance, which we argue can be overcome through planning and technology. We examined 4 conference models: a pure-virtual model and 3 hybrid hub-and-node models, where hubs stream content to local nodes. These models collectively aim to mitigate the logistical and administrative challenges of global knowledge transfer. Embracing virtual conferencing addresses 2 essential prerequisites of modern conferences: lowering carbon emissions and increasing accessibility for remote, time- and resource-poor researchers, particularly those from developing countries.

Using Salt Counterions to Modify ß2-Agonist Behavior in Vivo.

There is a paucity of data describing the impact of salt counterions on the biological performance of inhaled medicines in vivo. The aim of this study was to determine if the coadministration of salt counterions influenced the tissue permeability and airway smooth muscle relaxation potential of salbutamol, formoterol, and salmeterol. The results demonstrated that only salbutamol, when formulated with an excess of the 1-hydroxy-2-naphthoate (1H2NA) counterion, exhibited a superior bronchodilator effect (p < 0.05) compared to salbutamol base. The counterions aspartate, maleate, fumarate, and 1H2NA had no effect on the ability of formoterol or salmeterol to reduce airway resistance in vivo. Studies using guinea pig tracheal sections showed that the salbutamol:1H2NA combination resulted in a significantly faster (p < 0.05) rate of tissue transport compared to salbutamol base. Furthermore, when the relaxant activity of salbutamol was assessed in vitro using electrically stimulated, superfused preparations of guinea pig trachea, the inhibition of contraction by salbutamol in the presence of 1H2NA was greater than with salbutamol base (a total inhibition of 94.13%, p < 0.05). The reason for the modification of salbutamol's behavior upon administration with 1H2NA was assigned to ion-pair formation, which was identified using infrared spectroscopy. Ion-pair formation is known to modify a drug's physicochemical properties, and the data from this study suggested that the choice of counterion in inhaled pharmaceutical salts should be considered carefully as it has the potential to alter drug action in vivo.

New insights into eutectic cream skin penetration enhancement.

The manner in which the eutectic cream EMLA enhances the percutaneous penetration of lidocaine and prilocaine into human skin is still not fully understood. The purpose of this study was to investigate if the modification of drug aggregation played a role in the way EMLA facilitates delivery. Light scattering analysis of lidocaine alone in water gave a critical aggregation concentration (CAC) of 572 µM and a mean aggregate size of 58.8 nm. The analysis of prilocaine in identical conditions gave a CAC of 1177 µM and a mean aggregate size of 105.7 ± 24.8 nm. When the two drugs were mixed at their eutectic 1:1 ratio in water the CAC reduced to 165.8 µM and the aggregate size was 43.82 nm. This lidocaine-prilocaine interaction in water was further modified upon addition of polyoxyethylene hydrogenated castor oil, the surfactant in the EMLA aqueous phase, to produce aggregates of <20 nm. The physical characterisation data suggested that it was the EMLA cream's surfactant that modified the drug molecular interactions in the aqueous continuous phase and caused a 6 fold higher drug penetration through human epidermal tissue compared to the oil formulations tested in this study.

Triggered-release nanocapsules for drug delivery to the lungs.

This study demonstrated the feasibility of trigger-responsive inhaled delivery of medicines using soft solid shelled nanocapsules. The delivery system was a 50nm sized lipid rich capsule carrier that distended rapidly when mixed with an exogenous non-ionic surfactant trigger, Pluronic® L62D. Capsule distension was accompanied by solid shell permeabilisation which resulted in payload release from the carrier; 63.9±16.3% within 1h. In electrolyte rich aqueous fluids Pluronic® L62D was loosely aggregated, which we suggest to be the cause of its potency in lipid nanocapsule permeabilisation compared to other structurally similar molecules. The specificity of the interaction between L62D and the nanocapsule resulted in carrier payload delivery into human epithelial cells without any adverse effects on metabolic activity or barrier function. This effective, biocompatible, trigger-responsive delivery system provides a versatile platform technology for inhaled medicines.

Adenosine monophosphate is elevated in the bronchoalveolar lavage fluid of mice with acute respiratory toxicity induced by nanoparticles with high surface hydrophobicity.

Inhaled nanomaterials present a challenge to traditional methods and understanding of respiratory toxicology. In this study, a non-targeted metabolomics approach was used to investigate relationships between nanoparticle hydrophobicity, inflammatory outcomes and the metabolic fingerprint in bronchoalveolar fluid. Measures of acute lung toxicity were assessed following single-dose intratracheal administration of nanoparticles with varying surface hydrophobicity (i.e. pegylated lipid nanocapsules, polyvinyl acetate nanoparticles and polystyrene beads; listed in order of increasing hydrophobicity). Broncho-alveolar lavage (BAL) fluid was collected from mice exposed to nanoparticles at a surface area dose of 220 cm(2) and metabolite fingerprints were acquired via ultra pressure liquid chromatography-mass spectrometry-based metabolomics. Particles with high surface hydrophobicity were pro-inflammatory. Multivariate analysis of the resultant small molecule fingerprints revealed clear discrimination between the vehicle control and polystyrene beads (p < 0.05), as well as between nanoparticles of different surface hydrophobicity (p < 0.0001). Further investigation of the metabolic fingerprints revealed that adenosine monophosphate (AMP) concentration in BAL correlated with neutrophilia (p < 0.01), CXCL1 levels (p < 0.05) and nanoparticle surface hydrophobicity (p < 0.001). Our results suggest that extracellular AMP is an intermediary metabolite involved in adenine nucleotide-regulated neutrophilic inflammation as well as tissue damage, and could potentially be used to monitor nanoparticle-induced responses in the lung following pulmonary administration.