Curcumin Nanoparticles Attenuate Production Of Pro-Inflammatory Markers In Lipopolysaccharide-Induced Macrophages

Purpose: The surface charge of nanoparticles is an important factor that controls efficiency and cellular uptake. The aim of this study was to investigate curcumin nanoparticles (Cur-NPs) with different surface charges, in terms of toxicity, internalization, anti-inflammatory and anti-oxidant activities towards alveolar macrophages cells.

Methods: The surface charge of curcumin nanoparticles (positive, negative and neutral), with an average diameter of 30 nm, were synthesized and characterized. Polyvinyl-alcohol, polyvinylpyrrolidone and dextran were used as coatings to confer negative, positive and neutral charges. The synthesized Cur-NPs were evaluated for particle size, encapsulation efficiency, surface charge, qualitative and quantitative cellular uptakes , anti-oxidant and anti-inflammatory activities.

Results: Positively charged nanoparticles showed higher cytotoxicity effects compared to negative and neutral particles. The same trend was observed in antioxidant activity, which included radical scavenging and nitric oxide production. In addition, the anti- inflammatory activity (interleukin-1β, IL-6 and TNF-α) depleted in the order: positive>negative>neutral. The void neutral-, positively- and negatively-charged nanoparticles did not show any cytotoxic effects.

Conclusion: The difference in activity for different surface charges of Cur-NPs may be due to the internalization rate of the particles by alveolar macrophages. Intracellular uptake measurements demonstrated that Cur-NPs with positive surface charges possessed the strongest interaction with alveolar macrophages.

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An Investigation into the Powder Release Behaviour from Capsule-based Dry Powder Inhalers

A methodology for studying the deagglomeration performance and emptying behaviour of micronised mannitol powder from two commercial capsule-based dry powder inhalers (DPIs), the low (LR) and high resistance (HR) RS01®, is presented. Mathematical modeling played a key role in the interpretation of the powder release behaviour from these two DPI systems. Non-linear regression models were used to estimate the rate constants for emptying of mannitol powder, which were characterized from the aerosol obscuration versus time profiles obtained from laser diffraction particle sizing data. The effects of device resistance and associated pressure drops, sampling flow rate, rates of powder emptying and the presence of a capsule on the dispersion characteristics were studied. The presence of a capsule significantly improved the aerosolisation performance of mannitol powder from both inhalers, which may be due to the extended powder-air-device interactions within the device. It is important to consider the stochastic nature of movement and physical state of the capsule when assessing the aerosolisation mechanisms and dispersion performance from these complex delivery systems. The methodology set out in this study has the capacity to provide a greater level of detail in the study of aerosol plume characteristics from capsule-based DPIs.

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Biological effects of Simvastatin formulated as pMDI on Pulmonary Epithelial Cells.

Purpose: The aim of this study is to evaluate the biological effects of Calu-3 epithelial cells in response to the delivery of simvastatin (SV) via solution pressurized metered dose inhaler (pMDI).

Methods: SV pMDI was aerosolised onto Calu-3 air-interface epithelial cells using a modified glass twin stage impinger. The transport of SV across Calu-3 cells, mucus production, inflammatory cytokines production i.e. interleukin (IL) 6, 8 and tumour necrosis factor alpha (TNF- α) and oxidative stress from Calu-3 cells following treatment with SV pMDI was investigated and compared to untreated cells.

Results: It was found that SV had the ability to penetrate into the respiratory epithelium and convert into its active SV hydroxy acid (SVA) metabolite. Furthermore, the amount of mucus produced was significantly reduced when SV was deposited on Calu-3 compared to untreated cells. Additionally, SV delivered by pMDI reduces production of IL-6, 8 and TNF-α from Calu-3 following stimulation with lipopolysaccharide (LPS). SV also showed equivalent antioxidant property to vitamin E.

Conclusions: Treatment with SV solution pMDI formulation on Calu-3 cells reduces mucus production, inflammatory cytokines and oxidative stress. This formulation could potentially be used clinically as muco-inhibitory and anti-inflammatory therapy for treatment of chronic lung diseases.

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Mono- and co-cultures of bronchial and alveolar epithelial cells respond differently to pro-inflammatory stimuli and their modulation by salbutamol and budesonide.

Aim of this study was to investigate the changes in transport and effectiveness of salbutamol sulphate (SAL) and budesonide (BD) following stimulation with transforming growth factor-β (TGF-β) in mono- and co-culture models of bronchial and alveolar epithelium. Primary bronchial and alveolar epithelial cells, air interface grown on filters either as mono- cultures or in co- culture with airway smooth muscle cells or alveolar macrophages, respectively, were stimulated with TGF-β. The biological response was modulated by depositing aerosolized SAL on bronchial and BD on alveolar models, respectively. Barrier integrity, permeability to fluorescein-Na, transport of the deposited drug and the pharmacological response to SAL (cAMP and IL-8 levels) or BD (IL-6 and -8 levels) were measured. While stimulation with TGF-β did not have any significant effect on the transepithelial electrical resistance and permeability to fluorescein-Na in mono- and co- culture models, transport of SAL and BD were affected in cultures from some of the patients (6 out of 10 for bronchial and 2 out of 4 for alveolar cells). The bronchial co-culture showed a better responsiveness to SAL in terms of cAMP release than the monoculture. In contrast, difference between alveolar mono- and co- cultures to TGF-β mediated interleukin release and its modulation by BD was less pronounced. Our data point to intrinsic differences in the transport of and responsiveness to SAL and BD when epithelial cell cultures originate from different patients. Moreover, if the biological responses (e.g. IL-8, cAMP) involve communication between different cell types, co-culture models are more potent to measure such effects than mono-cultures.

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In vitro biological activity of resveratrol using a novel inhalable resveratrol spray-dried formulation.

The aim of the study was to prepare inhalable resveratrol by spray drying for the treatment of chronic obstructive pulmonary disease (COPD). Resveratrol, with a spherical morphology and particle diameter less than 5 μm, was successfully manufactured. Fine particle fraction (FPF) and mass median aerodynamic diameter (MMAD) of spray-dried resveratrol was 39.9 ± 1.1% and 3.7 ± 0.1 μm, respectively when assessed with an Andersen cascade impactor (ACI) at 60 l/min. The cytotoxicity results of spray-dried resveratrol on Calu-3 revealed that the cells could tolerate high concentration of resveratrol (up to 160 μM). In addition, in transport experiments using Snapwells, it was observed that more than 80% of the deposited dry powder was transported across the Calu-3 cells to the basal chamber within four hours. The expression of Interleukin-8 (IL-8) from Calu-3 induced with tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β1) and lipopolysaccharide (LPS) were significantly reduced after treatment with spray-dried resveratrol. The antioxidant assay (radical scavenging activity and nitric oxide production) showed spray-dried resveratrol to possess an equivalent antioxidant property as compared to vitamin C. Results presented in this investigation suggested that resveratrol could potentially be developed as a dry powder for inhalation for the treatment of inflammatory lung diseases like COPD.

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The ability of people with intellectual disability to use inhalers – an exploratory mixed methods study.

Objective: This aim of this study was to assess inhaler technique of people with intellectual disability (ID), and evaluate the effectiveness of teaching with respect to their individual ability to adopt correct technique. Methods: Seventeen people with ID were recruited through existing networks of general practitioners and disability support organisations. Inhaler technique was assessed using validated checklists and placebo devices, followed by provision of individualised training. The educational interaction between participant and researcher was captured via video recording and analysed qualitatively. Results: Seventeen people with ID participated; females comprised 65%. At baseline, no participants correctly used any device. Pressurised metered dose inhalers, with or without accessory devices, were the most poorly used devices. Inhalation steps were poorly performed across all devices. Following training, the proportions of assessed participants that were able to master inhaler technique were 100% of Accuhaler users, 40% of Turbuhaler users, 25% of pressurised metered dose inhaler users and 0% of Handihaler users. Barriers identified included poor comprehension of breathing processes, the lack of attentiveness and poor dexterity. Facilitators for educator delivery of inhaler technique education included the use of analogies and being patient. Conclusions: This is the first study to examine inhaler technique mastery in people with ID. Results show that with education that addresses the unique patient barriers inherent in this group, some individuals can be trained to mastery. Structured modules of inhaler technique training tailored for people with ID, but which can be individualised, are recommended.

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Development of an inhaled controlled release voriconazole dry powder formulation for the treatment of respiratory fungal infection.

The present research aimed to develop and characterise a sustained release dry powder inhalable formulation of voriconazole (VRZ) for invasive pulmonary aspergillosis. The developed formulations were studied for their in vitro release profile, aerosol and physico-chemical properties as well as interactions with lung epithelia in terms of toxicity and transport/uptake. VRZ and VRZ loaded poly lactide microparticles (VLM) were prepared by aqueous/organic co-solvent and organic spray drying respectively. Powders were characterised using laser diffraction, differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), dynamic vapor sorption (DVS) and electron microscopy. Aerosol performance was evaluated using an RS01 dry powder inhaler and in vitro cascade impaction. Uptake across Calu-3 lung epithelia was studied, using aerosol deposition of the powder onto cells cultured in an air interface configuration, and compared to dissolution using a conventional dialysis membrane. Additionally, toxicity of VRZ and VLM and the potential impact of transmembrane proteins on uptake were investigated. The particle size and the aerosol performance of spray dried VRZ and VLM were suitable for inhalation purposes. VRZ exhibited a median volume diameter of 4.52 ± 0.07 µm while VLM 2.40 ± 0.05 µm. Spray dried VRZ was crystalline and VLM amorphous as evaluated by DSC and XRPD and both powders exhibited low moisture sorption between 0 and 90% RH (<1.2% w/w) by DVS. The fine particle fraction (% aerosol < 5 µm) for the VRZ was 20.86 ± 1.98 % while the VLM showed significantly improved performance (p<0.01) with an FPF of 43.56 ± 0.13 %. Both VRZ and VLM were not cytotoxic over a VRZ concentration range of 1.2 nM to 30 µM and the VLM particles exhibited a sustained release over 48 hours after being deposited on the Calu-3 cell line or via conventional dialysis-based dissolution measurements. Lastly, VRZ exhibited polarized transport across epithelia with basal to apical transport being slower than apical to basal. Influx and efflux transports may also play a role as transport was altered in the presence of a number of inhibitors. This study has established an inhalable and sustained release powder of VRZ for targeting invasive pulmonary aspergillosis.

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Inhalable tranexamic acid for haemoptysiss treatment.

Purpose: An inhalable dry powder formulation of Tranexamic acid (TA) was developed and tested in a novel high-dose Orbital® multi-breath inhaler. The formulation was specifically intended for the treatment of pulmonary haemorrhage and wound healing associated with haemoptysis.

Methods: Inhalable TA particles were prepared by spray drying and the powder characterised using laser diffraction, electron microscopy, thermal analysis, moisture sorption and X-ray powder diffraction. The aerosol performance was evaluated using cascade impaction and inline laser diffraction and interaction with epithelia cells and wound healing capacity investigated using a Calu-3 air interface model.

Results: The spray dried TA particles were crystalline and spherical with a D0.5 of 3.35 μm. The powders were stable and had limited moisture sorption (0.307% w/w at 90% RH). The Orbital device delivered ca. 38 mg powder per ‘inhalation’ at 60 l.min-1 across four sequential shots with an overall fine particle fraction (≤6.4 µm) of 59.3 ± 3.5 % based on the emitted mass of ca. 150 mg. The TA particles were well tolerated by Calu-3 bronchial epithelia cells across a wide range of doses (from 1nM to 10 nM) and no increase in inflammatory mediators was observed after deposition of the particles (a decrease in of IL-1β, IL-8 and INFγ was observed). Time lapse microscopy of a damaged confluent epithelia indicated that wound closure was significantly greater in TA treated cells compared to control.

Conclusion: A stable, high performance aerosol of TA has been developed in a multi-breath DPI device that can be used for the treatment of pulmonary lesions and haemoptysis.

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Is the cellular uptake of respiratory aerosols delivered from different devices equivalent?

The study focuses on the application of a cell integrated modified Andersen Cascade Impactor (ACI) as an in vitro lung model for the evaluation of aerosols’ behaviour of different formulation devices, containing the same active drug, specifically nebuliser, pressurised metered dose inhaler (pMDI) and dry powder inhaler (DPI). Deposition and transport profiles of the three different inhaled salbutamol sulphate (SS) formulations with clinically relevant doses were evaluated using a modified ACI coupled with the air interface Calu-3 bronchial cell model. Reproducible amounts of SS were deposited on Snapwells for the different formulations, with no significant difference in SS deposition found between the standard ACI plate and modified plate. The transport of SS aerosols produced from pMDI formulation had similar transport kinetics to nebulised SS but significantly higher compared to the DPI, which could have led to the differences in clinical outcomes. Furthermore, drug absorption of different inhaled formulation devices of the same aerodynamic fraction were found not to be equivalent due to their physical chemical properties upon aerosolisation. This study has established an in vitro platform for the evaluation of the different inhaled formulations in physiologically relevant pulmonary conditions.

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The formulation of a pressurised metered dose inhaler containing theophylline for inhalation.

Background: Theophylline (TP) is a bronchodilator used orally to treat Chronic Obstructive Pulmonary Disease (COPD) that has been associated with multiple side effects, tempering its present use. This study aims to improve COPD treatment by creating a low-dose pressurized Metered Dose (pMDI) inhalable formulation of TP.

Methods: Aerosol performance was assessed using Andersen Cascade Impaction (ACI). Solubility of TP in HFA134/ethanol mixture was measured and morphology of the particles analyzed with a Scanning Electron Microscope (SEM). Calu-3 cell viability, epithelial cell transport and inflammatory-response assays were conducted to study the impact of the formulation on lung epithelial cells.

Results: The mass deposition profile of the formulation showed an emitted dose of 250.04 ± 14.48 µg per 5 actuations, achieving the designed nominal dose (50µg/dose). SEM showed that the emitted particles were hollow with spherical morphology. Approximately 98% of TP was transported across Calu-3 epithelial cells and the concentration of interleukin-8 secreted from Calu-3 cells following stimulation with tissue necrosis factor-α (TNF-α) resulted in significantly lower level of interleukin-8 released from the cells pre-treated with TP (1.92 ± 0.77 ng.ml-1 TP treated vs. 8.83 ± 2.05 ng.ml-1 TNF-α stimulated, respectively).

Conclusions: The solution pMDI formulation of TP developed in present study was shown to be suitable for inhalation and demonstrated anti-inflammatory effects at low doses in Calu-3 cell model.

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Synthesis and characterization of inhalable flavonoid nanoparticle for lung cancer cell targeting

Current cancer treatments are not adequate to cure cancer disease, as most chemotherapeutic drugs do not differentiate between cancerous and non-cancerous cells; which lead to systemic toxicity and adverse effects. We have developed a promising approach to deliver a potential anti-cancer compound (curcumin) for lung cancer treatment through pulmonary delivery. Three different sizes of curcumin micellar nanoparticles (Cur-NPs) were fabricated and their cytotoxicity effects (proliferation, apoptosis, cell cycle progression) were evaluated against non-small-cell lung cancer, human lung carcinoma (A549) and human lung adenocarcinoma (Calu-3). The in vitro cytotoxicity assay showed that Cur-NPs were more effective to kill lung cancer cells compared to DMSO-solubilised raw curcumin. The potency of the anti-cancer killing activities was size-dependent. Both raw curcumin and Cur-NPs were not toxic to healthy lung cells (BEAS-2B). Smaller Cur-NPs accumulated within nucleus, membrane and cytoplasm. Cur-NPs also induced apoptosis and caused G2/M arrest in both A549 and Calu-3 cell lines. Compared to raw curcumin, Cur-NPs were more effective in suppressing the expression of the inflammatory marker, Interleukin-8 (IL8). The aerosol performance of Cur-NPs was characterized using the next generation impactor (NGI). All Cur-NPs showed promising aerosolization property with mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) ranging between 4.8–5.2 and 2.0–2.1, respectively. This study suggests that inhaled curcumin nanoparticles could potentially be used for lung cancer treatment with minimal side effects. 

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Determination of Physical and Chemical Stability in Pressurised Metered Dose Inhalers (MDIs): Potential New Techniques

The pressurised metered dose inhaler (pMDI) is one of the oldest and most commonly prescribed therapeutic systems for drug delivery to the lung. pMDIs are subject to rigorous physical and chemical stability tests during formulation and prior to commercial approval. Due to the time and cost associated with formulation and product development studies, there is a need, especially within an industrial setting, for novel techniques that allow fast screening of new formulations in terms of physical and chemical (physico-chemical) stability. The key problem with achieving this goal is in the nature of pMDI formulations. While conventional intravenous, oral and topical formulations are in a solid-state at STP, pMDIs are by their definition, pressurised, making the direct observation of physico-chemical properties in situ, difficult.

This review highlights the state-of-the-art techniques and physico-chemical characterisation tools that can potentially enhance the formulation and product development process for pMDIs. Techniques investigated include: laser diffraction, Raman spectroscopy, isothermal ampoule calorimetry, titration calorimetry and gas perfusion calorimetry. These are discussed in the context of pharmaceutical development, with a focus on their use for the determination of the physical and chemical stability in pMDI delivery systems. The operational principles behind each technique are briefly discussed and complemented with examples from the literature. The strengths and weaknesses of the above techniques are highlighted with the purpose of guiding the reader to identify the most promising technique.

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Nano- and micro-based inhaled drug delivery systems for targeting alveolar macrophages.

This review focuses on the development of micro- and nanotechnology-based drug delivery systems to target alveolar macrophages in association with intracellular infections, cancer and lung inflammation. Aspects of nanoparticle and micron-sized particle engineering through exploitation of particles’ physicochemical characteristics such as particle size, surface charge and geometry of particles will be discussed in this review. In addition, the application of nano carriers such as liposomes, polymeric nanoparticles and dendrimers will be included with respect to macrophage targeting.

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Tuning the Orbital® DPI device: how to control delivery parameters and aerosol performance via modification of puck orifice geometry

The current study presents a new approach to tackle high dose lung delivery using a prototype multi-breath Orbital® DPI. One of the key device components is the ‘puck’ (aerosol sample chamber) with precision-engineered outlet orifice(s) that control the dosing rate. The influence of puck orifice geometry and hole number on the performance of mannitol aerosols were studied. Pucks with different orifice configurations were filled with 400 mg of spray-dried mannitol and tested in the Orbital® DPI prototype. The emitted dose and overall aerodynamic performance across a number of ‘breaths’ were studied using a MSLI. The aerosol performances of the individual actuations were investigated using in-line laser diffraction. The emptying rate of all pucks were linear between 20-80% cumulative drug released (R2 > 0.98) and the amount of formulation released per breath could be controlled such that the device was empty after 2 to 11 breath maneuvers. The puck-emptying rate linearly related to the orifice hole length (R2 > 0.95). Mass median aerodynamic diameters of the emitted aerosol ranged from 4.03 to 4.62 µm and FPF (≤ 6.4 µm) were 50-66%. Laser-diffraction suggested that the aerosol performance and emptying rates were not dependent on breath number, showing consistent size distribution profiles.

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Unique location but similar issues - working with health professionals in correctional services to improve inhaler use

Background: Correct inhaler technique is vital in the management of asthma and chronic obstructive pulmonary disease. However inhaler misuse is ubiquitous, and patients seldom receive effective education on how to use inhalers. Prisoners may have additional contributing factors for inhaler misuse i.e. low health literacy and intellectual disability. Consequently health professionals within correctional service facilities have a unique opportunity, and arguably an even more critical role, in training of inmates in inhaler use.
Aim: To evaluate correctional services health professionals’ baseline inhaler techniques; to assess the impact of training on inhaler techniques; and to evaluate the impact of the training on service delivery to inmates.
Method: Nurses, working in a correctional services hospital complex were recruited. Their baseline inhaler technique (i.e. prior to training) was assessed, using inhaler technique checklists. An education intervention was then delivered, following which participants’ inhaler technique was reassessed.
Results: A total of 23 nurses participated in the study. At baseline, proportions demonstrating correct technique were 42%, 0% and 5% for metered dose inhalers, Turbuhaler and Accuhaler respectively. Following training, there was a statistically significant increase in proportion of participants demonstrating correct inhaler techniques [84% (p=0.008), 84% (p=0.000) and 90% (p=0.000)].
Conclusion: Nurses in correctional care are expected to check inmates’ inhaler technique as part of clinical care, but were unable to use inhalers correctly, and need training in this regard. Pharmacists are well placed to provide this training. 

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The Effect of Active Pharmaceutical Ingredients on Aerosol Electrostatic Charges from Pressurized Metered Dose Inhalers.

Purpose:  This study investigated the effect of different active pharmaceutical ingredients (API) on aerosol electrostatic charges and aerosol performances for pressurised metered dose inhalers (pMDIs) using both insulating and conducting actuators.

Methods : Five solution-based pMDIs containing different API ingredients include beclomethasone dipropionate (BDP), budesonide (BUD), flunisolide (FS), salbutamol base (SB) and ipratropium bromide (IPBr) were prepared using pressure filled technique. Actuator blocks made from nylon, polytetrafluoroethylene (PTFE) and aluminum were manufactured with 0.3 mm nominal orifice diameter and cone nozzle shape. Aerosol electrostatics for each pMDI formulation and actuator were evaluated using electrical low-pressure impactor (ELPI) and the drug depositions were analysed using high performance liquid chromatography (HPLC).

Results : All three actuator materials showed the same net charge trend across the five active drug ingredients, with BDP, BUD and FS showing positive net charges ranging from 134.78 ± 127.29 pC to 332.74 ± 86.74 pC for both nylon and PTFE actuators. While SB and IPBr having significantly negative net charges across all three different actuators, which correlates to the ionic functional groups presented in the drug molecule structures.

Conclusions:  The API present in a pMDI has a dominant effect on the electrostatic properties of the formulation, overcoming the charge effect arising from the actuator materials. The results have shown that the electrostatic charges for a solution-based pMDI could be related to the interactions of the chemical ingredients and change in the work function for the overall formulation.

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A ‘soft spot’ for drug transport: modulation of cell stiffness using fatty acids and its impact on drug transport in lung model

The impact of a polyunsaturated fatty acid, arachidonic acid (AA), on membrane fluidity of epithelial cells and subsequent modulation of the drug transport was investigated. Membrane fluidity was assessed using molecular force microscopy. Calu-3 human bronchial epithelial cells were cultured on Transwell® inserts and the cell stiffness was assessed in the absence of fatty acids or in the presence of 30-μM AA. The morphology of the epithelial cells was distinctly different when AA was present, with the cell monolayer becoming more uniform. Furthermore the cell stiffness and variation in stiffness was lower in the presence of AA. In the fat-free medium, the median cell stiffness was 9.1kPa which dropped to 2.1kPa following exposure to AA. To further study this, transport of a common b2-agonist, salbutamol sulphate (SS) was measured in the presence of AA and in a fat free medium. The transport of SS was significantly higher when AA was present (0.61±0.09μg versus 0.11±0.003μg with and without AA respectively). It was evidenced that AA play a vital role in cell membrane fluidity and drug transport. This finding highlights the significance of the dietary fatty acids in transport and consequentially effectiveness of medications used to treat pulmonary diseases such as asthma.

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Implications and emerging control strategies for ventilator-associated infections.

Ventilator-associated pneumonia (VAP) remains a major burden to the healthcare system and intubated patients in intensive care units (ICU). In fact, VAP is responsible for at least 50% of prescribed antibiotics to patients who need mechanical ventilation. One of the factors contributing to VAP pathogenesis is believed to be rapid colonization of biofilm-forming pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus on the surface of inserted endotracheal tubes. These biofilms serve as a protective environment for bacterial colonies and provide enhanced resistance towards many antibiotics. This review presents and discusses an overview of current strategies to inhibit the colonization and formation of biofilm on endotracheal tubes, including antibiotic treatment, surface modification and antimicrobial agent incorporation onto endotracheal tube materials.

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Immunomodulatory Effects of a Low-dose Clarithromycin-based Macrolide Solution Pressurised Metered Dose Inhaler

Purpose: The aim of this study was to assess the effects of low-dose clarithromycin, formulated as pressurised metered dose inhaler, following deposition on the Calu-3 respiratory epithelial cells.

Methods: Clarithromycin was deposited on the air-interface culture of Calu-3 cells using a modified Andersen cascade impactor. Transport of fluorescein-Na, production of mucus and interleukin-8 release from Calu-3 cells following stimulation with transforming growth factor-β and treatment with clarithromycin was investigated.

Results: The deposition of clarithromycin had significant effect on the permeability of fluorescein-Na, suggesting that the barrier integrity was improved following a short-term treatment with clarithromycin (apparent permeability values were reduced to 3.57×10-9 ± 2.32×10-9 cm.s-1, compared to 1.14×10-8 ± 4.30×10-8 cm.s-1 for control). Furthermore, the amount of mucus produced was significantly reduced during the course of clarithromycin treatment. The concentration of interleukin-8 secreted from Calu-3 cells following stimulation with transforming growth factor-β resulted in significantly lower level of interleukin-8 released from the cells pre-treated with clarithromycin (5.2 ± 0.5 ng.ml-1 clarithromycin treated vs. 7.7 ± 0.8 ng.ml-1 control, respectively).

Conclusions: Our data demonstrate that treatment with clarithromycin decreases the paracellular permeability of epithelial cells, mucus secretion and interleukin-8 release and therefore, inhaled clarithromycin holds potential as an anti-inflammatory therapy.

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Murine pharmacokinetics of rifapentine delivered as an inhalable dry powder

In mouse models of tuberculosis infection, oral rifapentine-based regimens have demonstrated superior efficacy compared to current treatment options. However, these results were not replicated in recent human clinical trials due to limited rifapentine access into pulmonary granulomas. A novel inhalable rifapentine dry powder formulation could improve pulmonary rifapentine concentrations to rapidly treat infection. The pharmacokinetics of rifapentine in healthy mice was compared after intratracheal (IT) and intraperitoneal (IP) administration. Female BALB/c mice received rifapentine by IT or IP administration (20 mg/kg). Plasma, bronchoalveolar lavage (BAL) and tissue samples were harvested at each pre-specified time-point up to 24 hours and quantified. Concentration-time data were analysed using a mixed effects modelling approach to provide model-based estimates of area under the curve from time 0 to infinity (AUC0-∞). Whilst rifapentine was not detected in the BAL of mice dosed IP, IT delivery resulted in a maximum BAL fluid rifapentine concentration (25.2 ± 6.4 µg/mL) and an AUC0-∞ of 204.1 ± 67.8 mg/L.h. Between IT and IP delivery, the former had a considerably higher peak rifapentine lung concentration (321.3 ± 99.3 and 3.3 ± 1.2 µg/g, respectively) and AUC0-∞ (2614.4 ± 928.1 and 72.7 ± 24.9 mg/kg.h, respectively). The plasma AUC0-∞ after IT dry powder delivery (455.1 ± 132.4 mg/L.h) was approximately 4-fold smaller than the IP value (2010.1 ± 589.0 mg/L.h). Inhaled delivery of rifapentine has the potential to selectively enhance therapeutic efficacy at the pulmonary site of infection whilst minimising systemic exposure and related toxicity.

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