Triple combination dry powder formulation of pretomanid, moxifloxacin, and pyrazinamide for treatment of multidrug-resistant tuberculosis.

Both latent and multidrug-resistant tuberculosis (TB) have been causing significant concern worldwide. A novel drug, pretomanid (PA-824), has shown a potent bactericidal effect against both active and latent forms of Mycobacterium tuberculosis (MTb) and a synergistic effect when combined with pyrazinamide and moxifloxacin. This study aimed to develop triple combination spray dried inhalable formulations composed of antitubercular drugs, pretomanid, moxifloxacin, and pyrazinamide (1:2:8 w/w/w), alone (PaMP) and in combination with an aerosolization enhancer, L-leucine (20 % w/w, PaMPL). The formulation PaMPL consisted of hollow, spherical, dimpled particles (<5 µm) and showed good aerosolization behaviour with a fine particle fraction of 70 %. Solid-state characterization of formulations with and without L-leucine confirmed the amorphous nature of moxifloxacin and pretomanid and the crystalline nature of pyrazinamide with polymorphic transformation after the spray drying process. Further, the X-ray photoelectron spectroscopic analysis revealed the predominant surface composition of L-leucine on PaMPL dry powder particles. The dose-response cytotoxicity results showed pyrazinamide and moxifloxacin were non-toxic in both A549 and Calu-3 cell lines up to 150 µg/mL. However, the cell viability gradually decreased to 50 % when the pretomanid concentration increased to 150 µg/mL. The in vitro efficacy studies demonstrated that the triple combination formulation had more prominent antibacterial activity with a minimum inhibitory concentration (MIC) of 1 µg/mL against the MTb H37Rv strain as compared to individual drugs. In conclusion, the triple combination of pretomanid, moxifloxacin, and pyrazinamide as an inhalable dry powder formulation will potentially improve treatment efficacy with fewer systemic side effects in patients suffering from latent and multidrug-resistant TB.

Ancient Maya wetland fields revealed under tropical forest canopy from laser scanning and multiproxy evidence.

We report on a large area of ancient Maya wetland field systems in Belize, Central America, based on airborne lidar survey coupled with multiple proxies and radiocarbon dates that reveal ancient field uses and chronology. The lidar survey indicated four main areas of wetland complexes, including the Birds of Paradise wetland field complex that is five times larger than earlier remote and ground survey had indicated, and revealed a previously unknown wetland field complex that is even larger. The field systems date mainly to the Maya Late and Terminal Classic (∼1,400-1,000 y ago), but with evidence from as early as the Late Preclassic (∼1,800 y ago) and as late as the Early Postclassic (∼900 y ago). Previous study showed that these were polycultural systems that grew typical ancient Maya crops including maize, arrowroot, squash, avocado, and other fruits and harvested fauna. The wetland fields were active at a time of population expansion, landscape alteration, and droughts and could have been adaptations to all of these major shifts in Maya civilization. These wetland-farming systems add to the evidence for early and extensive human impacts on the global tropics. Broader evidence suggests a wide distribution of wetland agroecosystems across the Maya Lowlands and Americas, and we hypothesize the increase of atmospheric carbon dioxide and methane from burning, preparing, and maintaining these field systems contributed to the Early Anthropocene.

Evaluation of parylene derivatives for use as biomaterials for human astrocyte cell patterning.

Cell patterning is becoming increasingly popular in neuroscience because it allows for the control in the location and connectivity of cells. A recently developed cell patterning technology uses patterns of an organic polymer, parylene-C, on a background of SiO2. When cells are cultured on the parylene-C/SiO2 substrate they conform to the underlying parylene-C geometry. Parylene-C is, however, just one member of a family of parylene polymers that have varying chemical and physical properties. In this work, we investigate whether two commercially available mainstream parylene derivatives, parylene-D, parylene-N and a more recent parylene derivative, parylene-HT to determine if they enable higher fidelity hNT astrocyte cell patterning compared to parylene-C. We demonstrate that all parylene derivatives are compatible with the existing laser fabrication method. We then demonstrate that parylene-HT, parylene-D and parylene-N are suitable for use as an hNT astrocyte cell attractive substrate and result in an equal quality of patterning compared to parylene-C. This work supports the use of alternative parylene derivatives for applications where their different physical and chemical properties are more suitable.

Development and characterization of high payload combination dry powders of anti-tubercular drugs for treating pulmonary tuberculosis.

This study aimed to develop a high payload dry powder inhalation formulation containing a combination of the first line anti-tubercular drug, pyrazinamide, and the second line drug, moxifloxacin HCl. Individual powders of pyrazinamide (PSD) and moxifloxacin (MSD) and combination powders of the two drugs without (PM) and with 10% l-leucine (PML) and 10% DPPC (PMLD) were produced by spray drying. PSD contained >10 µm crystalline particles and showed poor aerosolization behaviour with a fine particle fraction (FPF) of 18.7 ±â€¯3.4%. PM produced spherical hollow particles with aerodynamic diameter < 5 µm and PML showed improved aerosolization with a high FPF of ~70%. However, PMLD showed a significantly reduced FPF (p > 0.05) compared to PML. Solid state studies and surface elemental analysis by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry confirmed the surface coating of particles contained amorphous moxifloxacin and both l-leucine and DPPC over crystalline pyrazinamide. Furthermore, pyrazinamide, moxifloxacin, PML and PMLD were found to display low toxicity to both A549 and Calu-3 cell lines even at a concentration of 100 µg/mL. In conclusion, a combination powder formulation of PML has the potential to deliver a high drug dose to the site of infection resulting in efficient treatment.

Manipulation of spray-drying conditions to develop dry powder particles with surfaces enriched in hydrophobic material to achieve high aerosolization of a hygroscopic drug.

This study aimed to develop dry powder particles with surfaces enriched in hydrophobic material by manipulation of spray-drying conditions and to investigate the effect of hydrophobic surface enrichment on aerosolization of hygroscopic drug. The composite dry powder formulations of kanamycin (hygroscopic drug) and rifampicin (hydrophobic drug) were produced by systematically (23 full factorial design) varying the drug ratio, co-solvent composition and inlet temperature using Buchi B-290 Mini Spray-Dryer. All the composite powder particles were inhalable in size (3.1-3.9 µm), wrinkled, flake-shaped and amorphous. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry showed that hydrophobic surface enrichment was significantly affected by co-solvent composition. Complete hydrophobic surface enrichment was achieved in one formulation (F7). The aerosolization efficiency by next generation impactor (NGI) showed that the composite formulations had higher fine particle fraction (FPF: >48.0%) than kanamycin-only formulation (FPF: 27.6%). Increase in hydrophobic surface enrichment (from 80.8 to 100%) decreased the powder density and increased FPF (from 48.0 to 77.2%). This is the first systematic study reporting the manipulation of spray-drying conditions for hydrophobic surface enrichment in composite dry powder particles and its effect on aerosolization. The high aerosolization efficiency of the combination formulations may be useful to deliver high doses of these drugs to treat lung infections.

The influence of surface active l-leucine and 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) in the improvement of aerosolization of pyrazinamide and moxifloxacin co-spray dried powders.

Pharmacotherapy of tuberculosis is potentially more efficient when delivered by the inhaled route than by the current oral and/or parenteral routes due to the higher concentration of drug reaching the primary region of infection in the lungs. This study investigated the influence of the amino acid l-leucine alone and in combination with the phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), on the aerosolization behaviour of the anti-TB drugs, pyrazinamide and moxifloxacin HCl. Spray dried powders of pyrazinamide (P), moxifloxacin (M) alone and in combination with 10% l-leucine (PL and ML) and 10% DPPC (PLD and MLD) were produced. The particle sizes of all powders except P were in the inhalable size range (<5 µm) but differ in their morphology in presence of the excipients. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed the migration of surface active l-leucine and DPPC onto the surface of the particles during the spray drying process. The aerosolization from a dry powder inhaler, Aerolizer®, using a Next Generation Impactor revealed fine particle fraction (FPF) values for P, PL and PLD of 18.7 ±â€¯3.4%, 53.0 ±â€¯3.2% and 74.5 ±â€¯5.3% respectively while FPF values for M, ML and MLD were 55.6 ±â€¯3.3%, 74.7 ±â€¯4.7% and 74.1 ±â€¯1.3% respectively. In conclusion, the differences in the aerosolization behaviours of the pyrazinamide and moxifloxacin spray dried powders with and without excipients was a combination of difference in the surface morphology and surface composition.

Atomic Force Microscopy and Angular-Dependent X-ray Photoelectron Spectroscopy Studies of Anchored Quaternary Ammonium Salt Biocides on Quartz Surfaces.

A siloxane surface-anchored quaternary ammonium salt (AQAS: BIOSAFE HM4100 in this study) has been chemisorbed onto a quartz substrate. The aim of this study is to elucidate, using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), the structure of the chemisorbed AQAS layers. The AQAS biocide includes a C18 alkyl chain previously invoked in lysis potency. The AQAS coverage appears in zones on the surface, which include a first layer (2.6 ± 0.1 nm) and multilayering that were explored using AFM. The XPS data exhibited two N 1s signals at about 402 and 399 eV, with only the former exhibiting angular dependence. This signal at 402 eV was assigned to the first anchored layer with perpendicular orientation determined by the AQAS anchoring to the surface. In preliminary AFM studies of bacteria on these AQAS surfaces, perturbations on the Staphylococcus aureus cells and the degradation of Escherichia coli cells suggest lysis potency.

Co-spray drying of hygroscopic kanamycin with the hydrophobic drug rifampicin to improve the aerosolization of kanamycin powder for treating respiratory infections.

High dose delivery of drugs to the lung using a dry powder inhaler (DPI) is an emerging approach to combat drug-resistant local infections. To achieve this, highly aerosolizable powders are required. We hypothesized that co-spray-drying kanamycin, a hydrophilic hygroscopic antibiotic, with rifampicin, a hydrophobic antibiotic, would produce inhalable particles with surfaces enriched in rifampicin. Such particles would have higher aerosolization than kanamycin alone, and minimise the mass of powder for inhalation avoiding use of non-active excipients. Kanamycin was co-spray-dried with rifampicin using a Buchi Mini Spray-dryer. All powders were inhalable in size (1.1-5.9 µm) and noncrystalline. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed the surface of the combination powder was enriched with rifampicin. In vitro aerosolization (fine particle fraction) determined by next generation impactor (NGI), dramatically improved from 29.5 ±â€¯0.2% (kanamycin-only) to 78.2 ±â€¯1.3% (kanamycin-rifampicin combination). The combination powder was flake-shaped in morphology, stable at 15% and 53% RH and 25 ±â€¯2 °C during one-month storage in an open Petri dish, and non-toxic (up to 50 µg/mL) to human alveolar and bronchial cell-lines. Surface enrichment of kanamycin by hydrophobic rifampicin improves aerosolization, which may help to combat drug-resistant local infections by facilitating high dose delivery to deep lung.

A Sustained Release Anchored Biocide System Utilizing the Honeycomb Cellular Structure of Expanded Perlite.

The development of a sustained-release biocide system, involving an anchored quaternary ammonium salt (AQAS) embedded in expanded perlite (EP) substrate, is reported. Scanning electron microscopy (SEM) images reveal the well-defined honeycomb cells that are a feature of EP. These honeycomb cells exhibit a variety of polygon shapes, which are filled with the AQAS molecules as evidenced by SEM data. The aqueous leaching of the AQAS from the EP honeycomb cells is monitored by the Fourier transform infrared CH stretching absorbance maxima at 2920 and 2850 cm-1. Solid-state NMR data indicate the formation of three dominant oligomeric forms of the AQAS biocide molecules formed within the EP network by condensation reactions at curing temperatures (160 °C). The various oligomeric species involve different numbers of SiO chains bonded to a central Si atom within the AQAS anchoring groups. Assays confirm the potency of the AQAS oligomers against Staphylococcus aureus and Escherichia coli bacteria.

Dry powder formulation of kanamycin with enhanced aerosolization efficiency for drug-resistant tuberculosis.

BACKGROUND: Kanamycin, an injectable agent, is currently used to treat drug-resistant tuberculosis (TB). Parenteral kanamycin causes high systemic toxicity which could be avoided by direct delivery to the lungs. This study focused on producing a highly aerosolizable dry-powder of hygroscopic kanamycin by spray-drying with l-leucine. METHODS: Kanamycin powders were prepared with different concentrations (0, 5, 10, 15 and 20% w/w) of l-leucine using the Buchi B-290 Mini Spray-Dryer. In vitro aerosolization efficiency, particle size, morphology, crystallinity, surface composition, drug-excipient interaction and moisture content of the powders were characterized by a Next Generation Impactor (NGI), laser diffraction, scanning electron microscopy, X-ray diffractometry, XPS, ATR-FTIR and thermogravimetric analysis. The physicochemical and aerosolization stability of the powders were investigated after one-month storage at 25±2°C/15% RH and 25±2°C/75% RH. The cytotoxicity on Calu-3 and A549 cells of the kanamycin powders was evaluated by MTT assay. RESULTS: The spray-dried powder particles were in the inhalable size range (<6.1µm). The powders with l-leucine were wrinkled in shape, amorphous in nature and had low moisture content (<5.0%). Kanamycin with 5% (w/w) of l-leucine showed the best aerosolization efficiency of 73.0±2.5%. The powders remained stable during storage at 25±2°C/15% RH and tolerated by respiratory cell lines. CONCLUSION: l-leucine improved the aerosolization of kanamycin by surface modification, which may be helpful for the effective treatment of drug-resistant tuberculosis.

'Going into the unknown': experiences of male patients in secure settings during environmental transition.

Little is known about the experiences of male patients in secure mental health and intellectual disability units during environmental transition. We interviewed patients before (n = 9) and after (n = 8) a side-to-side security transition from medium-secure wards in an older building to new wards in a purpose-built building. We inquired about transitional experiences in general and about this transition specifically. We examined interview transcripts and field notes using thematic analysis, and collated routine outcome data to gauge whether transition had obvious positive or negative effects. Qualitative analysis indicated three major themes (information, transition, and behaviour) and five overlapping subthemes (positive information sharing and consultation, concerns and anxieties about lack of information, life change and opportunity, home and sense of belonging, and potential conflict). Outcome data indicated little obvious change between first and second interviews. Expressed concerns of patients about transition were largely about tangible and practical issues, including changes to rules, including smoking and prohibited items. The results highlight the need for the development of supportive patient-inclusion strategies, consistent and transparent communication processes, and a published timeframe during the planning and implementation phases of all types of transitional moves, including the side-to-side transfer of residents between accommodation buildings.

Response of right ventricular size to treatment with cardiac resynchronization therapy and the risk of ventricular tachyarrhythmias in MADIT-CRT.

BACKGROUND: Cardiac resynchronization therapy (CRT) is increasingly recognized for its ability to reduce ventricular tachyarrhythmias, possibly associated with left ventricular reverse remodeling, but the role of the right ventricle (RV) in this process has not been examined. OBJECTIVE: The purpose of this study was to investigate the relationship between ventricular tachyarrhythmias and change in RV dimensions in patients receiving CRT with a defibrillator (CRT-D). METHODS: Multivariate Cox proportional hazards regression modeling was used to assess the risk for fast (≥180 bpm) ventricular tachycardia/ventricular fibrillation (VT/VF) or death by baseline and follow-up RV size (defined as right ventricular end-diastolic area [RVEDA]) among 1495 patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT). RESULTS: Multivariate analysis showed that treatment with CRT-D was independently associated with a 27% (P = .003) reduction in the risk of VT/VF or death among patients with larger RVs (>first quartile RVEDA ≥13 mm(2)/m(2)) compared with implantable cardioverter-defibrillator (ICD)-only therapy, whereas in patients with smaller RVs there was no significant difference in the risk of VT/VF between the 2 treatment arms (hazard ratio = 1.00, P = .99). At 1-year follow-up, CRT-D patients displayed significantly greater reductions in RVEDA compared to ICD-only patients (P <.001), associated with a corresponding reduction in the risk of subsequent VT/VF or death (>first quartile reduction in RVEDA with CRT-D vs ICD-only: hazard ratio = 0.55, P <.001) independent of changes in left ventricular dimensions. CONCLUSION: Our findings suggest that the RV may have an important role in determining the antiarrhythmic effect of CRT independent of the effect of the device on the left ventricle.

Protection and functionalisation of silver as an optical sensing platform for highly sensitive SPR based analysis.

Silver thin films are well known as the most sensitive material for surface plasmon resonance (SPR) based analysis. However, the use of silver for this purpose is limited by three main issues, namely poor adhesion to plastic substrates, chemical instability in both air and aqueous environments and hence the difficulty in functionalizing the silver coated substrate for immobilizing biomolecular ligands by conventional liquid phase methods. In this work, we have successfully addressed these problems using gas-phase coating processes. We demonstrate highly adherent sputter-deposited silver coatings on low cost polymer substrates using a sputter-deposited thin gold adhesion layer. The problems of chemical instability and functionalisation have been addressed by using the gas phase process of plasma enhanced chemical vapour deposition (PECVD) to deposit thin films with a base SiO(x)C(y)H(z) layer (using tetraethyl orthosilicate precursor) functionalised with carboxylic acid (from sequential deposition with acrylic acid precursor). The resultant coating serves as a protective layer against degradation of the optical properties of silver under long term storage and use in ambient conditions. The reactive carboxyl functionality is used for the covalent immobilization of biomolecules. The successful stabilisation and functionalization of silver films on plastic sensor chips is demonstrated by mouse IgG immunoassays. The expected superior performance of the silver thin films over gold thin films for SPR analysis is demonstrated.

Multi-layered plasma-polymerized chips for SPR-based detection.

The surface functionalization of a noble metal is crucial in a surface plasmon resonance-based biomolecular detection system because the interfacial coating must retain the activity of immobilized biomolecules while enhancing the optimal loading. We present here a one-step, room-temperature, high-speed, gas-phase plasma polymerization process for functionalizing gold substrates using siloxane as an adhesion layer and acrylic acid as a functional layer. Siloxane- and thiol-based coatings were compared for their performance as adhesion and the interfacial layer for subsequent functionalization. An in situ sequential deposition of siloxane and acrylic acid resulted in a 7-fold increase in carboxylic functionality surfacial content compared to films deposited with thiol-containing precursors. Grading of the layer composition achieved as a consequence of ion-induced mixing on the surface coating under the application of the plasma is confirmed through secondary ion mass spectroscopic studies. DNA hybridization assays were demonstrated on gold/glass substrates using surface plasmon enhanced ellipsometry and the applicability of this coating for protein immunoassays were demonstrated with plasma functionalized gold/plastic substrates in Biacore 3000 SPR instrument.

Phase I trial with biomarker studies of vatalanib (PTK787) in patients with newly diagnosed glioblastoma treated with enzyme inducing anti-epileptic drugs and standard radiation and temozolomide.

Targeting angiogenesis in glioblastoma (GBM) may improve patient outcome by normalizing tumor vasculature and improving delivery of chemotherapeutics and oxygen. Consequently, concomitant administration of small molecule inhibitors of the VEGF pathway will likely have a positive impact on chemoradiation treatment outcome. We conducted a Phase I study of vatalanib, a small molecule inhibitor of VEGFR, PDGFR, and c-kit in patients with newly diagnosed GBM receiving radiation, temozolomide, and an enzyme-inducing anti-epileptic drug in order to determine the MTD of vatalanib in this patient population. We incorporated circulating biomarker and SNP analyses and pharmacokinetic studies. Nineteen patients were enrolled and the MTD was not reached at the time of study termination. Vatalanib was well tolerated with only 2 DLTs (thrombocytopenia and elevated transaminases). Other grade 3/4 toxicities included leukopenia, lymphopenia, neutropenia, and hand-foot syndrome. There were no wound-healing complications. Of the 13 patients evaluable for a radiographic response, 2 had a partial response and 9 had stable disease. Vatalanib significantly increased PlGF and sVEGFR1 in plasma circulation and decreased sVEGFR2 and sTie2. Plasma collagen IV increased significantly by day 50 of treatment. Vatalanib was well tolerated and this study demonstrates the safety of oral small molecule inhibitors in newly diagnosed GBM patients. Blood biomarkers may be useful as pharmacodynamic markers of response to anti-angiogenic therapies.

Plasma functionalization of AFM tips for measurement of chemical interactions.

In this paper, a new, fast, reproducible technique for atomic force microscopy (AFM) tips functionalization used for chemical interaction measurements is described. Precisely, the deposition of an aminated precursor is performed through plasma-enhanced chemical vapor deposition (PECVD) in order to create amine functional groups on the AFM tip and cantilever. The advantages of the precursor, aminopropyltriethoxysilane (APTES), were recently demonstrated for amine layer formation through PECVD deposition on polymeric surfaces. We extended this procedure to functionalize AFM probes. Titration force spectroscopy highlights the successful functionalization of AFM tips as well as their stability and use under different environmental conditions.

Functionalization of cycloolefin polymer surfaces by plasma-enhanced chemical vapour deposition: comprehensive characterization and analysis of the contact surface and the bulk of aminosiloxane coatings.

The surface science of bioassay devices is of great importance in the development of modern diagnostic platforms. The quality of surface is one of the most important elements of the device, often governing the background response, hence controlling the sensitivity of an assay. Detailed surface characterization and analysis are imperative for the preparation of reproducible coatings with desired properties. We performed a comprehensive characterization of 3-aminopropyl-triethoxysilane films prepared under two different deposition conditions on COP slides. Two sets of slides were prepared, by exposing them to plasma reaction for 30 seconds (A30 slide) and 4 minutes (A4 slide). While the variations in the deposition conditions seemed very subtle, the use of several powerful analytical tools helped us to reveal some fundamental differences between the studied films in terms of binding capacity, swelling and adhesion. Overall, the A30 films, with a thickness of 5.12 nm, showed up to 40% higher binding capacity and 25% better adhesion than the thicker A4 coatings (28.15 nm). Upon contact with aqueous media, a significant change was observed in terms of surface roughness. The A30 slides outperformed A4 slides, resulting in smoother surface, which is an important parameter for biomolecule immobilisation. The use of the techniques described in this article is aimed to set new standards for the characterization and analysis of the substrate surface of the future diagnostic devices.

In situ characterization of aluminum-containing mineral-microorganism aqueous suspensions using scanning transmission X-ray microscopy.

In situ characterization of colloidal particles under hydrous conditions is one of the key requirements for understanding their state of aggregation and impact on the transport of pollutants in aqueous environments. Scanning transmission X-ray microscopy (STXM) is one of the few techniques that can satisfy this need by providing element- and chemical-state-specific 2-D maps at a spatial resolution better than 50 nm using soft X-rays from synchrotron radiation wiggler or undulator sources tuned to the absorption edges of different elements. X-ray absorption near-edge structure (XANES) spectra can also be collected simultaneously at a similar spatial resolution and can provide phase identification in many cases. In this study, we report STXM images and XANES spectroscopy measurements at or above the Al K-edge (E = 1559.6 eV) of various Al-containing minerals and synthetic oxides [alpha-Al2O3 (corundum), gamma-Al2O3, gamma-AlOOH (boehmite), alpha-Al(OH)3 (bayerite), KAl2(AlSi3O10)(OH)2 (muscovite), (Al,Mg)8(Si4O10)4(OH)8.nH2O (montmorillonite), and Mg6Al2(OH)16CO3.4H2O (hydrotalcite)] and demonstrate the capability of this spectromicroscopic tool to identify different Al-containing mineral colloids in multiphase mixtures in aqueous solution. We also demonstrate that STXM imaging at or above the C K-edge (E = 284.2 eV) and Al K-edge can provide unique information on the interactions between bacteria and Al-containing nanoparticles in aqueous suspensions. STXM images of a mixture of Caulobacter crescentus and montmorillonite and corundum particles just above the C and Al K-edges show that the mineral particles and bacteria are closely associated in aggregates, which is likely due to the binding of bacteria to clay and corundum particles by extracellular polysaccharides.