No / Competition experiments in which 1,2-phenylenediamine, C6H4(NH2)2, condenses with equimolar quantities of benzil, (C6H5CO)2, and a 3,3'- or 4,4'-disubstituted benzil (XC6H4CO)2 (X = F, Cl, Br, CH3 or CH3O) to form a mixture of 2,3-diphenylquinoxaline and the corresponding 2,3-diarylquinoxaline (Ar = XC6H4) in the microdroplets produced in a nebuliser allow a Hammett relationship with a ρ value of 1.85 to be developed for this accelerated condensation in the nebuliser. This structure reactivity relationship reveals that an appreciable amount of negative charge builds up on the carbon of the carbonyl group of the benzil during the rate-limiting step of the reaction, thus confirming that this process involves nucleophilic addition of the 1,2-phenylenediamine to the benzil. In general, the presence of an electron donating substituent, particularly in the 4 and 4' positions, in the benzil retards the reaction, whereas an electron attracting substituent, especially in the 3 and 3' position, accelerates it. / 2019 British Mass Spectrometry Summer Studentship for NWF.

Yes / Background: Chronic infections with Pseudomonas aeruginosa are a leading cause of morbidity in patients with cystic fibrosis (CF). The aim of tobramycin inhalation therapy in CF patients with chronic pulmonary infection is to deliver high amounts of drug directly to the site of infection. TOBI® is a tobramycin nebulizer solution (300 mg/5 ml) approved by FDA for maintenance therapy for patient with CF. The 20% tobramycin sulfate solution was reported as the optimal and maximal concentration. Methods: Nebulization of high strength tobramycin solution (20% tobramycin sulfate) (HSTS) has been assessed in this study by using different selected high performance nebulizer delivery systems: two different designs of jet nebulizers, and three new nebulizers based on vibrating mesh technology. The aerosol particle size distribution and output characteristics were measured for in vitro performance assessment of the nebulizer systems. The methodology was adapted from the current European standard, EN 13544-1:2001E. Results: The particle size distribution characteristic measurements showed that all tested nebulizers may be suitable for inhalation of HSTS. The mean (SD) of highest percentage of fine particles (<5 mm) was 77.64 (2.3) % for Sidestream®, at flow rate 16 L/min. The highest respirable inhaled mass was for Pari LC Plus® combined with PariBoyN® compressor, with mean (SD) 90.85 (8.6) mg. The mean (SD) of highest drug wastage percentage was 63.9 (3.9) % for Sidestream® jet nebulizer combined with compressed air cylinder at flow rate 16 L/min, while the lowest was 2.3 (0.26) % for NE-U22 Omron® (high frequency). Conclusions: The HSTS can be nebulized by all tested nebulisers but the high frequency NE-U22 Omron® and Aeroneb Go® are more efficient. When the HSTS compared to TOBI®, the respirable inhaled dose was increased to more than 73%.

Yes / Extensive research has demonstrated the potential effectiveness of curcumin against various diseases, including asthma and cancers. However, few studies have used liquid-based vehicles in the preparation of curcumin formulations. Therefore, the current study proposed the use of nanoemulsion and microsuspension formulations to prepare nebulised curcuminoid for lung delivery. Furthermore, this work expressed a new approach to understanding the aerosol performance of nanoparticles compared to microsuspension formulations. The genotoxicity of the formulations was also assessed. Curcuminoid nanoemulsion formulations were prepared in three concentrations (100, 250 and 500 µg/ml) using limonene and oleic acid as oil phases, while microsuspension solutions were prepared by suspending curcuminoid particles in isotonic solution (saline solution) of 0.02% Tween 80. The average fine particle fraction (FPF) and mass median aerodynamic diameter (MMAD) of the nebulised microsuspension formulations ranged from 26% and 7.1 µm to 40% and 5.7 µm, for 1000 µg/ml and 100 µg/ml respectively. In a comparison of the low and high drug concentrations of the nebulised nanoemulsion, the average FPF and MMAD of the nebulised nanoemulsion formulations prepared with limonene oil ranged from 50% and 4.6 µm to 45% and 5.6 µm, respectively; whereas the FPF and MMAD of the nebulised nanoemulsion prepared with oleic acid oil ranged from 46% and 4.9 µm to 44% and 5.6 µm, respectively. The aerosol performance of the microsuspension formulations were concentration dependent, while the nanoemulsion formulations did not appear to be dependent on the curcuminoids concentration. The performance and genotoxicity results of the formulations suggest the suitability of these preparations for further inhalation studies in animals.

Curcuminoids have strong anticancer activities but have low bioavailability. The highest rate of cancer deaths comes from lung tumours; therefore, inhaled curcuminoids could treat lung cancer locally. To date, there are no nebulised formulations of curcuminoids, and there are no inhalable curcuminoids particles without excipients using air jet mill and sonocrystallisation methods for DPI formulations. It is the first time; the aerodynamic parameters of curcumin, demethoxycurcumin and bisdemethoxycurcumin were measured individually using NGI. The size, shape, free surface energy, and the crystal polymorphism of the produced inhalable curcuminoid particles were characterised using laser diffraction, SEM, IGC, DSC and XRPD, respectively. Several DPI formulations with a variable particle size of curcuminoids were prepared in two drug-carrier ratios (1:9 and 1:67.5). The best performance of the DPI formulations of the sonocrystallised particles, which exist in crystal structure form1, were obtained from ethanol- heptane, as illustrated FPF 43.4%, 43.6% and 43.4% with MMAD of 3.6µm, 3.5µm and 3.4µm, whereas the best DPI formulation of the air jet milled particles was presented FPF 38.0%, 38.9%, and 39.5% with MMAD of 3.6µm, 3.4µm and 3.2µm for curcumin, demethoxycurcumin and bisdemethoxycurcumin, respectively. Nebulised curcuminoids using nanoemulsion and microsuspension formulations were prepared. The physical properties, such as osmolality, pH and the viscosity of the aerosolised nanoemulsion and the microsuspension formulations were determined. The FPF% and MMAD of nebulised nanoemulsion ranged from 44% to 50% and from 4.5µm to 5.5µm respectively. In contrast, the FPF% of microsuspension ranged from 26% to 40% and the MMAD from 5.8µm to 7.05µm. A HPLC method was developed and validated in order to be used in the determination of curcuminoids from an aqueous solution.

Yes / TOBI® is a recently marketed preservative and sulphate free tobramycin formulation approved by FDA for maintenance therapy for patient with cystic fibrosis. The performance of selected recent nebuliser delivery systems has been assessed using the developed method to determine the optimum combinations to deliver approved tobramycin inhaled solution (TOBI)®. A simple, sensitive and specific high performance liquid chromatographic method has been developed and used to quantitative determination of the aminoglycoside tobramycin following pre-column derivatisation with phenylisocyanate (PIC). The reaction time was 10 min at 80º C and the resulting derivative was stable for five days at room temperature. The quantitative performance of the assay was further improved by using another aminoglycoside (neomycin) as internal standard. The stable resulting PIC-tobramycin derivative was separated using a HPLC 5μm Columbus C18 column (150x4.60 mm i.d, Phenomenex). The mobile phase was consisted of acetonitrile-glacial acetic acid-water (450:5:545, v/v/v) and ultraviolet detection at (240 nm). The proposed method showed good validation data. The standard curve was linear (n=5) at seven different concentrations, ranging from 20 to 140μg/ml and the correlation coefficient (R2) of the regression line was 0.9995. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.86μg/ml and 2.62μg/ml, respectively. The relative standard deviation (RSD %) was less than 0.6% for intra-day assay (n=5) and 2.5% for inter-day assay (n=5). A number of nebuliser performance comparison studies have been demonstrated for aerosolise TOBI® to choice the optimum combination produces high repirable inhaled mass of tobramycin. The objective of this study was to evaluate the performance of recent nebuliser delivery systems to nebulise approved tobramycin inhaled solution (TOBI)®.

No description available.

The full text will be available at the end of the embargo: 9th May 2024

An issue of inhalation therapy is a complex topic, actively discussed in last decades, and its progress in various scientific fields is more than required. First part of this thesis brings a theoretical introduction into principles of aerosol therapy and into the requirements resulting from them. Commonly available technologies of inhalers and nebulisers for medical usage, parameters that determinate their effectivity are briefly described. Usage mistakes influencing the effectivity of inhalation are discussed, as well. Second part deals with experimental measurements of aerosol that selected inhalers generate. It also describes difficulties connected with the methods of these measurements, with sampling and following analyses. Gained results are compared with an available literature.