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Independent lung ventilation (ILV) is a life-saving procedure in unilateral pulmonary pathologies. ILV is underused in clinical practice, mostly due to the technically demanding placement of a double lumen endotracheal tube (ETT). Moreover, the determination of ventilation parameters for each lung in vivo is limited. In recent years, the development of 3D printing techniques enabled the production of highly accurate physical models of anatomical structures used for in vitro research, considering the high risk of in vivo studies. The purpose of this study was to assess the influence of double-lumen ETT on the gas transport and mixing in the anatomically accurate 3D-printed model of the bronchial tree, with lung lobes of different compliances, using various ventilation modes. The bronchial tree was obtained from Respiratory Drug Delivery (RDD Online, Richmond, VA, USA), processed and printed by a dual extruder FFF 3D printer. The test system was also composed of left side double-lumen endotracheal tube, Siemens Test Lung 190 and anesthetic breathing bag (as lobes). Pressure and flow measurements were taken at the outlets of the secondary bronchus. The measured resistance increased six times in the presence of double-lumen ETT. Differences between the flow distribution to the less and more compliant lobe were more significant for the airways with double-lumen ETT. The ability to predict the actual flow distribution in model airways is necessary to conduct effective ILV in clinical conditions.

The aim of this study was to investigate the effect of changing processing variables on the impulse electrostatic droplet formation, being the first and crucial step during manufacture of novel particles and capsules intended for drug delivery. A factorial design was performed to assess the consequences of altering selected parameters: liquid dynamic viscosity, nozzle inner diameter, liquid flow rate and electric voltage. Pure glycerol and glycerol aqueous solution (c = 85 %wt) were used as model substances and the process of droplet formation was analyzed. The results of this study can be applied to controlled formulation of droplets during impulse electrostatic atomization.

Health effects of inhaling aerosol produced by electronic cigarettes (ECs) are still uncertain. This work analyzes ECs as specific inhalation devices, which can be characterized by aerodynamic resistance, size distribution of released droplets, and predicted regional and total lung deposition as a function of inhalation maneuver.The internal resistance of two types of EC and a conventional cigarette was evaluated by measuring ΔP-Q curves. Particle size distribution in EC-emitted mist was determined by laser diffraction. The measured data were used to calculate lung deposition based on two approaches: multipath particle dosimetry model (MPPD) and Finlay-Martin correlations. Computations were done for the set of ventilation parameters of an EC user, and also for a by-stander.Tested ECs had higher aerodynamic resistance (1.6-1.9 mbar(0.5) min/L) than tobacco cigarette (0.56 mbar(0.5) min/L), and these values are much above the high-resistant DPIs. The average mass median diameter of droplets emitted from ECs was 410 nm, with the average GSD = 1.6. Predicted total lung deposition of the mainstream aerosol was 15%-45% depending on the breathing scheme. An expected increase of particle size in the exhaled aerosol led to predictions of 15%-30% deposition efficiency during passive vaping.ECs are characterized by high inhalatory resistance, so they require stronger physical effort to transfer cloud of droplets to the lungs, as compared, for example, to DPIs. A significant amount of aerosol is then exhaled, forming an unintentional source of particles to which by-standers are exposed. From this perspective, ECs are not optimal personal aerosol delivery devices.

Understanding the influence of process conditions on the properties of pharmaceutical products is critical to their optimal and cost-effective design and manufacture. The aim of this study was to investigate the effect of changing processing variables on the physical properties of spray-dried mannitol and co-spray-dried mannitol/disodium cromoglycate (DSCG) formulations intended for therapeutic inhalation. A 24 full factorial design was performed to assess the consequences of altering the following spray-drying parameters: feed flow rate, nozzle gas flow rate, drying gas inlet temperature, and aspirator capacity (drying gas flow rate). Aqueous solutions of mannitol and mannitol/DSCG were spray-dried using a laboratory-scale spray dryer, and the products were characterized in terms of particle size distribution, powder yield, and particle morphology. These physical properties were found to be affected mainly by two processing variables: nozzle gas flow rate and drying gas inlet temperature. In addition, op...

Assessing the influence of therapeutic formulations on biophysical properties of lung surfactant is an essential step in optimal design of pharmaceutical products intended for inhalation. In the present study, maximum bubble pressure (MBP) tensiometry was employed to evaluate the physicochemical impact of several novel multifunctional composite powders, suitable for drug delivery by inhalation, on the dynamic activity of model pulmonary surfactant at the air–water interface. Bi- and tri-component powders consisted of mannitol or dextran, N-acetylcysteine and disodium cromoglycate were obtained by spray drying technique and subsequently their interaction with modified bovine surfactant extract (Survanta) were analysed. Several dynamic surface tension parameters were investigated as measures of alteration of surface activity in Survanta-powder solutions. All discussed powders demonstrated significant impact on surface activity of Survanta solution, either positive or negative, depending on powders composition and concentration. Although it is problematic to explain all observed effects in the framework of known mechanisms, the present study provides a new insight into the possible changes in the dynamic interfacial behaviour of pulmonary surfactant after therapeutic interventions. Obtained results may be applied during development of more effective and safe medical products suitable for drug delivery by inhalation.