State-of-the-art review of the application and development of various methods of aerosol therapy.

Aerosol therapy is a rapidly developing field of science. Due to a number of advantages, the administration of drugs to the body with the use of aerosol therapy is becoming more and more popular. Spraying drugs into the patient's lungs has a significant advantage over other methods of administering drugs to the body, including injection and oral methods. In order to conduct proper and effective aerosol therapy, it is necessary to become familiar with the basic principles and applications of aerosol therapy under various conditions. The effectiveness of inhalation depends on many factors, but most of all on: the physicochemical properties of the sprayed system, the design of the medical inhaler and its correct application, the dynamics of inhalation (i.e. the frequency of breathing and the volume of inhaled air). It is worth emphasizing that respiratory system diseases are one of the most frequently occurring and fastest growing diseases in the world. Accordingly, in recent years, a significant increase in the number of new spraying devices and pharmaceutical drugs for spraying has appeared on the market. It should also be remembered that the process of spraying a liquid is a complicated and complex process, and its efficiency is very often characterized by the use of micro- and macro parameters (including average droplet diameters or the spectrum of droplet diameter distribution). In order to determine the effectiveness of the atomization process and in the delivery of drugs to the patient's respiratory tract, the analysis of the size of the generated aerosol droplets is most often performed. Based on the proposed literature review, it has been shown that many papers dealt with the issues related to aerosol therapy, the selection of an appropriate spraying device, the possibility of modifying the spraying devices in order to increase the effectiveness of inhalation, and the possibility of occurrence of certain discrepancies resulting from the use of various measurement methods to determine the characteristics of the generated aerosol. The literature review presented in the paper was prepared in order to better understand the spraying process. Moreover, it can be helpful in choosing the right medical inhaler for a given liquid with specific rheological properties. The experimental data contained in this study are of great cognitive importance and may be of interest to entities involved in pharmaceutical product engineering (in particular in the case of the production of drugs containing liquids with complex rheological properties).

The thermostated medical jet nebulizer: Aerosol characteristics.

The sudden expansion of gas at the outlet of the jet (pneumatic) nebulizer significantly reduces the temperature of the solution, which may provoke bronchospasm, therefore it is recommended to use modern pneumatic inhalers equipped with a thermostat or a universal thermal attachment that allow to obtain a higher temperature aerosol, i.e. thermo-aerosol. The research was carried out for model Newtonian fluids. The droplet diameters of the aerosol spray were investigated using a Spraytec aerosol particle size measurement system. Analysis of the obtained results showed that the increase in solution viscosity caused a decrease in mean droplet diameters and prolonged nebulization time. The analysis of experimental data made it possible to propose a correlation equation describing the mean diameter of the droplets depending on the properties of the liquid and the flow conditions in the thermostated medical nebulizer. The obtained data contributes to a better understanding of the complex liquid atomisation process and can be helpful in the design of medical nebulizers and pharmaceutical preparations.

The effect of shear and extensional viscosity on atomization in medical inhaler.

The paper contains the results of experimental studies of water, aqueous solutions of glycerol and aqueous solutions of glycerol-polyethylene oxide (PEO) atomization process in a medical inhaler obtained by the use of the digital microphotography method. The effect of the shear and extensional viscosity on the drop size, drop size histogram and mean drop diameter has been analyzed. The obtained results have shown that the drop size increases with the increase in shear and extensional viscosity of liquid atomized. Extensional viscosity has a greater impact on the spraying process. It has been shown that the change in liquid viscosity leads to significant changes in drop size distribution. The correlation for Sauter mean diameter as function of the shear and extensional viscosity was proposed.