Drug output of unvented jet nebulizers as a function of time

Abstract

Nebulizer drug output rate increases during the nebulization. For unvented jet nebulizers, a physical and mathematical model based on the efficiency of the nebulization process is presented for this phenomenon. Formulas are derived for the cumulative drug output and the drug output rate of the nebulization process. The model is compared with the model proposed by Coates et al. [J. Aerosol. Med. 11 (1998) 101]. Both models are supported by experimental literature data. Both models predict the experimental values well but the proposed model allows more easy prediction of the influence of small changes in the nebulization conditions and the calculation of the cumulative drug output for a related process. From literature data it is shown that the efficiency of an unvented jet nebulization process of diluted aqueous solutions is relatively insensitive to small changes in the concentration as well as to small changes in aspiration flow but is sensitive to the humidity of the compressor gas only.

Nebulization as a tool for photosensitizer delivery to the respiratory tract

“…During the experiment, we observed that the concentration of the compound in the remaining solution increased as the nebulization progressed (Figure ). We proposed that the droplets formed carried less photosensitizer than the concentration of the solution, as it had been previously proposed by Diederik et al in 2003 . According to this model, as the concentration increased the droplets would have to have more compound in then, increasing the delivery over time.…”

Aerosol Drug Delivery to the Lungs

“…As a nebulizer is operated, the concentration of dissolved drug in the solvent will gradually increase as a result of solvent evaporation [135] . This effect can lead to increases in drug output rate as nebulization progresses [136] . However, jet nebulizers also become cooler during operation as a result of solvent evaporation [135] , and the increase in solvent viscosity with decreasing temperature can be expected to reduce the drug output rate [5] .…”

Nebulization as a tool for the delivery of photosensitizers in the photodynamic inactivation of respiratory diseases

“…We proposed that the droplets formed carried less photosensitizer than the concentration of the solution, as it had been previously proposed by Diederik and co-workers in 2003. 62 The concern about stability in the nebulization of many pharmaceuticals and the known degradation of ICG in water motivated a deep investigation of stability. [76][77] To make sure that the process of droplet formation would not increase the degradation kinetics in any way, we studied the chemical composition of the three photosensitizer solutions with HPLC-MS-UV.…”