ORCID Profile
0000-0002-3251-5194
Current Organisations
University of Sydney
,
University of Queensland
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Publisher: Elsevier BV
Date: 2021
DOI: 10.1016/J.ADDR.2021.114066
Abstract: Antimicrobial peptides and proteins (APPs) are becoming increasingly important in targeting multidrug-resistant (MDR) bacteria. APPs is a rapidly emerging area with novel molecules being produced and further optimised to enhance antimicrobial efficacy, while overcoming issues associated with biologics such as potential toxicity and low bioavailability resulting from short half-life. Inhalation delivery of these agents can be an effective treatment of respiratory infections owing to the high local drug concentration in the lungs with lower exposure to systemic circulation hence reducing systemic toxicity. This review describes the recent studies on inhaled APPs, including in vitro and in vivo antimicrobial activities, toxicity assessments, and formulation strategies whenever available. The review also includes studies on combination of APPs with other antimicrobial agents to achieve enhanced synergistic antimicrobial effect. Since different APPs have different biological and chemical stabilities, a targeted formulation strategy should be considered for developing stable and inhalable antimicrobial peptides and proteins. These strategies include the use of sodium chloride to reduce electrostatic interaction between APP and extracellular DNA in sputum, the use of D-enantiomers or dendrimers to minimise protease-mediated degradation and or the use of prodrugs to reduce toxicity. Although great effort has been put towards optimising the biological functions of APPs, studies assessing biological stability in inhalable aerosols are scarce, particularly for novel molecules. As such, formulation and manufacture of inhalable liquid and powder formulations of APPs are underexplored, yet they are crucial areas of research for clinical translation.
Publisher: AME Publishing Company
Date: 04-2021
DOI: 10.21037/ATM-20-3946
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 15-02-2019
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 12-2020
Publisher: MDPI AG
Date: 25-04-2022
DOI: 10.3390/ANTIBIOTICS11050570
Abstract: Infections caused by multidrug-resistant (MDR) bacteria have highlighted the importance of the development of new antimicrobial agents. While bacteriophages (phages) are widely studied as alternative agents to antibiotics, combined treatments using phages and antibiotics have exhibited Phage–Antibiotic Synergy (PAS), in which antibiotics promote phage replication and extraordinary antimicrobial efficacy with reduced development of bacterial resistance. This review paper on the current progress of phage–antibiotic therapy includes aspects of the mechanisms of PAS and the therapeutic performance of PAS in combating multidrug-resistant bacterial infections. The choice of phages and antibiotics, the administration time and sequence, and the concentrations of the two agents impact the bacterial inhibitory effects to different extents.
Publisher: Medknow
Date: 2014
Publisher: Elsevier BV
Date: 06-2023
Publisher: Springer Science and Business Media LLC
Date: 07-09-2022
DOI: 10.1007/S11095-022-03363-2
Abstract: Dry powder inhalation formulations have become increasingly popular for local and systemic delivery of small molecules and biotherapeutics. Powder formulations provide distinct advantages over liquid formulations such as elimination of cold chain due to room temperature stability, improved portability, and the potential for increasing patient adherence. To become a viable product, it is essential to develop formulations that are stable (physically, chemically and/or biologically) and inhalable over the shelf-life. Physical particulate properties such as particle size, morphology and density, as well as chemical properties can significantly impact aerosol performance of the powder. This review will cover these critical attributes that can be engineered to enhance the dispersibility of inhalation powder formulations. Challenges in particle engineering for biotherapeutics will be assessed, followed by formulation strategies for overcoming the hurdles. Finally, the review will discuss recent ex les of successful dry powder biotherapeutic formulations for inhalation delivery that have been clinically assessed.
Publisher: Elsevier BV
Date: 09-2020
DOI: 10.1016/J.CMI.2020.04.039
Abstract: Pan-drug-resistant (PDR) Pseudomonas aeruginosa is one of the three top-priority pathogens identified by the WHO, and bacteriophages have been investigated as an alternative therapy. However, knowledge on the pharmacokinetics harmacodynamics (PK/PD) of phage therapy is sparse, limiting its clinical applications. This study aimed to evaluate the PK/PD of the antipseudomonal phage øPEV20 in vivo following intravenous administration. Healthy Sprague-Dawley rats were given øPEV20 as a single intravenous bolus of ~6, 9 and 11-log A three-compartment model with non-linear clearance described the exposure of øPEV20 in blood. Model evaluation indicated that the model was robust and parameter estimates were accurate. The median (standard error) values of model-predicted PK parameters for V We developed a robust PK model to describe the disposition of phages in healthy rats. This model may have significant potential in facilitating future preclinical and clinical PK/PD investigations.
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 07-2022
DOI: 10.1016/J.CMI.2022.01.006
Abstract: Inhaled phage therapy has been revisited as a potential treatment option for respiratory infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa however, there is a distinct gap in understanding the dose-response effect. The aim of this study was to investigate the dose-response effect of Pseudomonas-targeting phage PEV31 delivered by pulmonary route in a mouse lung infection model. Neutropenic BALB/c mice were infected with MDR P. aeruginosa (2×10 At 24-h post-infection, all the phage-treated groups exhibited a significant reduction in pulmonary bacterial load by 1.3-1.9 log This study provides dose-response effect of inhaled phage therapy that may guide dose selection for treating P. aeruginosa respiratory infections in humans.
Publisher: Springer Science and Business Media LLC
Date: 23-06-2017
DOI: 10.1007/S11095-017-2213-4
Abstract: To compare titer reduction and delivery rate of active anti-tuberculosis bacteriophage (phage) D29 with three inhalation devices. Phage D29 lysate was lified to a titer of 11.8 ± 0.3 log Respective titer reductions for the vibrating mesh nebulizer, jet nebulizer, and soft mist inhaler were 0.4 ± 0.1, 3.7 ± 0.1, and 0.6 ± 0.3 log Delivering active phage requires a prudent choice of inhalation device. The jet nebulizer was not a good choice for aerosolizing phage D29 under the tested conditions, due to substantial titer reduction likely occurring during droplet production. The vibrating mesh nebulizer is recommended for animal inhalation studies requiring large amounts of D29 aerosol, whereas the soft mist inhaler may be useful for self-administration of D29 aerosol.
Publisher: Springer Science and Business Media LLC
Date: 06-10-2021
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.NEUINT.2015.04.004
Abstract: Brain tissue from Alzheimer's disease patients exhibits synaptic degeneration in selected regions. Synaptic dysfunction occurs early in the disease and is a primary pathological target for treatment. The molecular mechanisms underlying this degeneration remain unknown. Quantifying the synaptic proteome in autopsy brain and comparing tissue from Alzheimer's disease cases and subjects with normal aging are critical to understanding the molecular mechanisms associated with Alzheimer pathology. We isolated synaptosomes from hippoc us and motor cortex so as to reduce s le complexity relative to whole-tissue homogenates. Synaptosomal extracts were subjected to strong cation exchange (SCX) fractionation to further partition s le complexity each fraction received SWATH-based information-dependent acquisition to generate a comprehensive peptide-ion library. The expression of synaptic proteins from AD hippoc us and motor cortex was then compared between groups. A total of 2077 unique proteins were identified at a critical local false discovery rate <5%. Thirty of these, including 17 novel proteins, exhibited significant expression differences between cases and controls these proteins are involved in cellular functions including structural maintenance, signal transduction, autophagy, oxidative stress, and proteasome activity, or they have synaptic-vesicle related or energy-related functions. Differentially expressed proteins were subjected to pathway analysis to identify protein-protein interactions. This revealed that the most perturbed molecular and cellular functions were cellular assembly and organization. Core analysis revealed RhoA signaling to be the top canonical pathway. Network analysis showed that differentially expressed proteins were related to cellular assembly and organization, and cellular function and maintenance. This is the first study to combine SCX fractionation with SWATH analysis. SWATH is a promising new technique that can greatly enhance protein identification in any proteome, and has many other benefits however, there are limitations yet to be resolved.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.NEUINT.2014.05.011
Abstract: Brain tissue from Alzheimer's disease (AD) patients shows significant loss of synapses in selected regions. Synaptic degeneration is the best predictor for loss of cognitive functions ante mortem. The molecular mechanisms underlying this degeneration remain unknown. Our previous two-dimensional gel-electrophoresis proteomics study found that 26 synaptic proteins are differentially expressed in Alzheimer's brain. It is difficult to quantify global protein expression using this technique because (a) several proteins can migrate together and (b) isoforms of the same protein can migrate to different places. The present study estimated global synaptic protein levels by label-free multiple reaction monitoring. Multiple reaction monitoring is a powerful and sensitive mass spectrometry technique that specifically targets multiple protein of interests. The severely AD-affected hippoc us was compared with motor cortex, a relatively spared region. We targeted ten proteins in autopsy brain based on the earlier study. Analytes separated by high performance liquid-chromatography were monitored on a hybrid triple quadrupole linear ion trap mass spectrometer in multiple reaction monitoring mode. With the use of an internal standard protein, linear and highly reproducible (CV<9%) label-free assays were achieved. Data were contrasted with the gel-based study to highlight differences and similarities. Significantly higher expression levels of peroxiredoxin-1 (may provide antioxidant protection) and dihydropyrimidinase-related protein-1 (associated with cytoskeletal remodeling) were found in AD hippoc us. Significantly lower levels of peroxiredoxin-1 and the energy-related enzymes creatine kinase B and fructose-bisphosphate aldolase C were found in non-AD hippoc us. Our previously reported difference in synaptotagmin expression is probably isoform-specific. These findings suggest potential roles of key proteins in synaptic loss in AD, and/or a protective mechanism in non-AD brain tissue.
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.EJPB.2022.05.014
Abstract: Bacteriophage (phage) therapy is a promising treatment strategy to combat antibiotic-resistant bacteria. Clinical reports from a century ago, as well as recent reports have revealed safety and efficacy of phage therapy for bacterial wound infections. However, the conventional liquid phage formulation and delivery platforms reported lack of dose control as it easily runs off from the infection site and it is impossible to determine total volume transfer. The aim of this study was to formulate phage liquids for topical delivery using a metered-dose spray. Two types of anti-Pseudomonas phages, PEV1 (myovirus) and PEV31 (podovirus) were formulated in 35% ethanol in water containing non-ionic polymers. The formulations were evaluated for physical properties, ease of spray, dripping upon spraying, drying time, in vitro release profiles, antibacterial activity, and storage stability. The optimized phage-polymer spray formulations were easily sprayable with minimal dripping and fast drying time. Phages were rapidly released from the formulation and inhibited the growth of Pseudomonas aeruginosa. Both PEV1 and PEV31 remained biologically stable in the optimized formulations during storage at 4 °C for eight weeks. This study showed the topical spray formulations containing non-ionic polymers in ethanol/water could be a promising and innovative therapeutic system for delivering phages.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 09-2019
Publisher: Mary Ann Liebert Inc
Date: 04-2021
Publisher: American Society for Microbiology
Date: 02-2018
DOI: 10.1128/AAC.01714-17
Abstract: Bacteriophage therapy is a promising alternative treatment to antibiotics, as it has been documented to be efficacious against multidrug-resistant bacteria with minimal side effects. Several groups have demonstrated the efficacy of phage suspension in vivo to treat lung infections using intranasal delivery however, phage dry-powder administration to the lungs has not yet been explored. Powder formulations provide potential advantages over a liquid formulation, including easy storage, transport, and administration. The purpose of this study was to assess the bactericidal activities of phage dry-powder formulations against multidrug-resistant (MDR) strain Pseudomonas aeruginosa FADDI-PA001 in a mouse lung infection model. Phage PEV20 spray dried with lactose and leucine produced an inhalable powder at a concentration of 2 × 10 7 PFU/mg. P. aeruginosa lung infection was established by intratracheal administration of the bacterial suspension to neutropenic mice. At 2 h after the bacterial challenge, the infected mice were treated with 2 mg of the phage powder using a dry-powder insufflator. At 24 h after the phage treatment, the bacterial load in the lungs was decreased by 5.3 log 10 ( P 0.0005) in the phage-treated group compared with that in the nontreated group. Additionally, the phage concentration in the lungs was increased by 1 log 10 at 24 h in the treated group. These results demonstrate the feasibility of a pulmonary delivery of phage PEV20 dry-powder formulation for the treatment of lung infection caused by antibiotic-resistant P. aeruginosa .
Publisher: Wiley
Date: 15-11-2013
DOI: 10.1016/J.JALZ.2012.04.009
Abstract: Synaptic dysfunction occurs early in Alzheimer's disease (AD) and is recognized to be a primary pathological target for treatment. Synapse degeneration or dysfunction contributes to clinical signs of dementia through altered neuronal communication the degree of synaptic loss correlates strongly with cognitive impairment. The molecular mechanisms underlying synaptic degeneration are still unclear, and identifying abnormally expressed synaptic proteins in AD brain will help to elucidate such mechanisms and to identify therapeutic targets that might slow AD progression. Synaptosomal fractions from human autopsy brain tissue from subjects with AD (n = 6) and without AD (n = 6) were compared using two-dimensional differential in-gel electrophoresis. AD pathology is region specific human subjects can be highly variable in age, medication, and other factors. To counter these factors, two vulnerable areas (the hippoc us and the temporal cortex) were compared with two relatively spared areas (the motor and occipital cortices) within each group. Proteins exhibiting significant changes in expression were identified (≥20% change, Newman-Keuls P value < .05) using either matrix-assisted laser desorption ionization time-of-flight or electrospray ionisation quadrupole-time of flight mass spectrometry. Twenty-six different synaptic proteins exhibited more than twofold differences in expression between AD and normal subjects. These proteins are involved in regulating different cellular functions, including energy metabolism, signal transduction, vesicle transport, structure, and antioxidant activity. Comparative proteome analysis uncovered markers of pathogenic mechanisms involved in synaptic dysfunction.
Publisher: MDPI AG
Date: 29-01-2021
DOI: 10.3390/ANTIBIOTICS10020130
Abstract: Antibiotic resistance remains as an unresolved global challenge in the health care system, posing serious threats to global health. As an alternative to antibiotics, bacteriophage (phage) therapy is rising as a key to combating antibiotic-resistant bacterial infections. In order to deliver a phage to the site of infection, hydrogels have been formulated to incorporate phages, owing to its favorable characteristics in delivering biological molecules. This paper reviews the formulation of phage-delivering hydrogels for orthopedic implant-associated bone infection, catheter-associated urinary tract infection and trauma-associated wound infection, with a focus on the preparation methods, stability, efficacy and safety of hydrogels as phage carriers.
Publisher: Elsevier BV
Date: 11-2018
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.ADDR.2016.05.011
Abstract: Tuberculosis (TB) is an intracellular infectious disease caused by the airborne bacterium, Mycobacterium tuberculosis. Despite considerable research efforts, the treatment of TB continues to be a great challenge in part due to the requirement of prolonged therapy with multiple high-dose drugs and associated side effects. The delivery of pharmacological agents directly to the respiratory system, following the natural route of infection, represents a logical therapeutic approach for treatment or vaccination against TB. Pulmonary delivery is non-invasive, avoids first-pass metabolism in the liver and enables targeting of therapeutic agents to the infection site. Inhaled delivery also potentially reduces the dose requirement and the accompanying side effects. Dry powder is a stable formulation of drug that can be stored without refrigeration compared to liquids and suspensions. The dry powder inhalers are easy to use and suitable for high-dose formulations. This review focuses on the current innovations of inhalable dry powder formulations of drug and vaccine delivery for TB, including the powder production method, preclinical and clinical evaluations of inhaled dry powder over the last decade. Finally, the risks associated with pulmonary therapy are addressed. A novel dry powder formulation with high percentages of respirable particles coupled with a cost effective inhaler device is an appealing platform for TB drug delivery.
Publisher: Elsevier BV
Date: 10-2021
DOI: 10.1016/J.ADDR.2021.113952
Abstract: In vitro-in vivo correlation is the establishment of a predictive relationship between in vitro and in vivo data. In the context of cascade impactor results of orally inhaled pharmaceutical aerosols, this involves the linking of parameters such as the emitted dose, fine particle dose, fine particle fraction, and mass median aerodynamic diameter to in vivo lung deposition from scintigraphy data. If the dissolution and absorption processes after deposition are adequately understood, the correlation may be extended to the pharmacokinetics and pharmacodynamics of the delivered drugs. Correlation of impactor data to lung deposition is a relatively new research area that has been gaining recent interest. Although few in number, experiments and meta-analyses have been conducted to examine such correlations. An artificial neural network approach has also been employed to analyse the complex relationships between multiple factors and responses. However, much research is needed to generate more data to obtain robust correlations. These predictive models will be useful in improving the efficiency in product development by reducing the need of expensive and lengthy clinical trials.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.IJPHARM.2018.09.061
Abstract: Tobramycin (TOB) and clarithromycin (CLA) can potentially be used synergistically for the treatment of respiratory infections caused by Pseudomonas aeruginosa (P. aeruginosa) in cystic fibrosis (CF) patients. This study aimed to develop a novel combination proliposome formulation (TOB/CLA-CPROLips) containing both hydrophilic TOB and hydrophobic CLA via a core-carrier approach. The combination proliposomes were produced by spray drying a suspension comprising spray-driedmannitol (SD-MAN, 0.45%) and spray-dried tobramycin (SD-TOB, 0.05%) particles suspended in an ethanolic lipid solution of CLA (0.05%). The lipid layer coated on the surface of the dry proliposome particles conferred moisture protection and sustained drug release properties in comparison to the pure drugs. The optimized TOB/CLA-CPROLips formulation was stable after 3 months of storage at 60% relative humidity (RH) and 25 °C. The combination drug proliposomes showed a synergistic antimicrobial activity against planktonic cells and biofilm cultures of P. aeruginosa. In conclusion, the core-carrier method coupled with spray-drying provided a novel approach for the preparation of combination antibiotics proliposomes.
Publisher: Mary Ann Liebert Inc
Date: 02-2020
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 12-2017
Publisher: MDPI AG
Date: 14-08-2021
DOI: 10.3390/PHARMACEUTICS13081260
Abstract: The coronavirus disease 2019 (COVID-19) is an unprecedented pandemic that has severely impacted global public health and the economy. Hydroxychloroquine administered orally to COVID-19 patients was ineffective, but its antiviral and anti-inflammatory actions were observed in vitro. The lack of efficacy in vivo could be due to the inefficiency of the oral route in attaining high drug concentration in the lungs. Delivering hydroxychloroquine by inhalation may be a promising alternative for direct targeting with minimal systemic exposure. This paper reports on the characterisation of isotonic, pH-neutral hydroxychloroquine sulphate (HCQS) solutions for nebulisation for COVID-19. They can be prepared, sterilised, and nebulised for testing as an investigational new drug for treating this infection. The 20, 50, and 100 mg/mL HCQS solutions were stable for at least 15 days without refrigeration when stored in darkness. They were atomised from Aerogen Solo Ultra vibrating mesh nebulisers (1 mL of each of the three concentrations and, in addition, 1.5 mL of 100 mg/mL) to form droplets having a median volumetric diameter of 4.3–5.2 µm, with about 50–60% of the aerosol by volume 5 µm. The aerosol droplet size decreased (from 4.95 to 4.34 µm) with increasing drug concentration (from 20 to 100 mg/mL). As the drug concentration and liquid volume increased, the nebulisation duration increased from 3 to 11 min. The emitted doses ranged from 9.1 to 75.9 mg, depending on the concentration and volume nebulised. The HCQS solutions appear suitable for preclinical and clinical studies for potential COVID-19 treatment.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 12-2022
DOI: 10.1016/J.ADDR.2022.114561
Abstract: Dry powder inhalers (DPIs) can be used with a wide range of drugs such as small molecules and biologics and offer several advantages for inhaled therapy. Early DPI products were intended to treat asthma and lung chronic inflammatory disease by administering low-dose, high-potency drugs blended with lactose carrier particles. The use of lactose blends is still the most common approach to aid powder flowability and dose metering in DPI products. However, this conventional approach may not meet the high demand for formulation physical stability, aerosolisation performance, and bioavailability. To overcome these issues, innovative techniques coupled with modification of the traditional methods have been explored to engineer particles for enhanced drug delivery. Different particle engineering techniques have been utilised depending on the types of the active pharmaceutical ingredient (e.g., small molecules, peptides, proteins, cells) and the inhaled dose. This review discusses the challenges of formulating DPI formulations of low-dose and high-dose small molecule drugs, and biologics, followed by recent and emerging particle engineering strategies utilised in developing the right inhalable powder formulations for enhanced drug delivery.
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.ADDR.2022.114378
Abstract: Antibiotic therapy has become increasingly ineffective against bacterial infections due to the rise of resistance. In particular, ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) have caused life-threatening infections in humans and represent a major global health threat due to a high degree of antibiotic resistance. To respond to this urgent call, novel strategies are urgently needed, such as bacteriophages (or phages), phage-encoded enzymes, immunomodulators and monoclonal antibodies. This review critically analyses these promising antimicrobial therapies for the treatment of multidrug-resistant bacterial infections. Recent advances in these novel therapeutic strategies are discussed, focusing on preclinical and clinical investigations, as well as combinatorial approaches. In this 'Bad Bugs, No Drugs' era, novel therapeutic strategies can play a key role in treating deadly infections and help extend the lifetime of antibiotics.
Publisher: Springer Science and Business Media LLC
Date: 04-04-2019
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.JNEUMETH.2014.02.016
Abstract: The recent introduction of multiple reaction monitoring to proteomics research has allowed many researchers to apply this technique to study human diseases. Here we combine subcellular fractionation of human autopsy brain with label-free multiple reaction monitoring to quantitatively analyse proteins in synapses. The protein enolase, from Streptococcus pyogenes serotype M6, which is sufficiently different from human proteins, was spiked into the s le mixture prior to trypsin digestion and used as an internal standard across s les. Three synaptic proteins and an internal standard analysed with four injections over four consecutive days gave consistent differences with a coefficient of variation of <4%. Consistent retention time was recorded across the replicates. Comparison with existing methods: Previously, multiple reaction monitoring analysis has been utilized to study human autopsy and animal tissues. Utilizing the synaptosomal fraction prior to analysis reduced s le complexity and allowed the enriched synaptic proteins to be quantitatively assessed in a highly reproducible manner, without the need for expensive fluorescent labels and synthetic peptides. Protein expression can be measured with accuracy using label-free multiple reaction monitoring mass spectrometry in relatively complex human brain s les. Synaptic functions are critical for neuronal communication and function, and synapse dysfunction underlies many neurodegenerative diseases, including Alzheimer's disease. This method can be applied to study a range of brain disorders.
Publisher: Informa UK Limited
Date: 31-08-2020
Publisher: Elsevier BV
Date: 03-2023
Publisher: Wiley
Date: 14-04-2020
DOI: 10.1002/BTM2.10159
Publisher: Wiley
Date: 07-08-2020
DOI: 10.1111/BPH.15197
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.EJPB.2022.03.003
Abstract: Although inhalation powder aerosols of antibiotics have been used to treat respiratory infections caused by Pseudomonas aeruginosa, biofilms are difficult to clear. Ciprofloxacin and D-amino acids (D-Met, D-Trp and D-Phe) were shown to facilitate P. aeruginosa biofilm removal. Spray dried powders for inhalation tend to be amorphous, hence unstable to moisture which causes deterioration in the aerosol performance. Hydrophobic L-amino acids such as leucine can impart moisture protection. In this study, we hypothesized that co-spray dried formulations of ciprofloxacin and hydrophobic D-amino acids will offer the combined benefits of both anti-biofilm and moisture protection properties. Of the three D-amino acids tested, D-Met and D-Trp (at 5 mM) but not D-Phe reduced clinical isolate P. aeruginosa biofilm loads and the extent of biofilm clearance was further enhanced in the presence of ciprofloxacin. Subsequently, ciprofloxacin was spray dried alone or in combination with 30% (w/w) D-Met or D-Trp. The biological and physicochemical properties of the powders were assessed, including the minimum inhibitory concentration, anti-biofilm activity, particle size distribution and morphology, solid-state properties, water sorption, and aerosol performance. The spray dried combination powders were physically stable and inhalable with fine particle fraction (<5 µm) values of 50-57% when aerosolized. The powders exhibited enhanced anti-biofilm activity compared with ciprofloxacin alone. The presence of D-amino acids provided moisture protection, with the recrystallization event shifting from 50% RH to 80% RH in powders containing D-Trp. In conclusion, the use of D-amino acids (D-Met or D-Trp) is an attractive formulation strategy which offers dual benefits of anti-biofilm effect and moisture protection.
Publisher: American Society for Microbiology
Date: 16-12-2020
DOI: 10.1128/AAC.01470-20
Abstract: Inhaled bacteriophage (phage) therapy is a potential alternative to conventional antibiotic therapy to combat multidrug-resistant (MDR) Pseudomonas aeruginosa infections. However, pharmacokinetics (PK) and pharmacodynamics (PD) of phages are fundamentally different from antibiotics and the lack of understanding potentially limits optimal dosing. The aim of this study was to investigate the in vivo PK and PD profiles of antipseudomonal phage PEV31 delivered by pulmonary route in immune-suppressed mice.
Publisher: American Chemical Society (ACS)
Date: 20-09-2019
DOI: 10.1021/ACS.ANALCHEM.9B02282
Abstract: Use of powder phage formulations for the treatment of multiple-drug-resistant pulmonary infections is gaining attention. To achieve therapeutic benefits, it is critical for phages to remain stable in the formulation. Assessment of phage stability relies on plaque assay (bioactivity), which requires powder s les to be reconstituted in liquid. The purpose of this study was to develop an innovative approach using photothermal-induced resonance-enhanced atomic force microscopy infrared spectroscopy (AFM-IR) to assess the presence of phages and investigate their protein conformation in the solid state. Staphylococcal phage S83 was spray-dried with lactose and sodium stearate using spray-drying. The phage powder recrystallized at 60% relative humidity (RH), so it was stored and handled below this RH. For the AFM-IR measurements, spray-dried Staphylococcal phage Sa83 powder was embedded in resin, followed by microtome sectioning. AFM-IR spectra collected from different regions within the microtomed sections revealed the presence of phage proteins with amide I and amide II bands at 1640 and 1550 cm
No related grants have been discovered for Rachel Yoon Kyung Chang.