Theory and calculation of ejection atomizers

Glukhov, S. A.

doi:10.1007/bf00562485

Cited by 1 publication

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“…This is based on a number of published mathematical expressions, which describe the factors that influence droplet size. Glukhov (1969) However, there is no term in equation 3.1 that describes the influence of fluid viscosity on droplet size. An alternative model, proposed by Rizkalla et al (1974), in a study of air-blast atomisers, stressed the importance that both surface tension and viscosity have upon the droplet size (equation 3.2).…”

Section: Introductionmentioning

confidence: 99%

Nebulisers for the generation of liposomal aerosols

Bridges

Taylor

1998

International Journal of Pharmaceutics

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The thesis details investigations into the use of various types of medical nebuliser for the generation of liposomal aerosols. Chapter 1 provides a comprehensive introduction to the theory and practice of drug delivery to the respiratory tract. It also reviews the potential applications of inhaled liposomes to drug delivery, and the devices used to generate liposomal aerosols.A preliminary investigation into the physicochemical attributes of liposomes which may. influence aerosol generation is detailed in chapter 2. These include studies of the stability of liposome bilayers to disruptive energy (ie. membrane extrusion and sonication), investigations of the surface tension and viscosity of liposomes, and also the release of a liposomally entrapped hydrophilic marker. Chapter 3 demonstrates how these physicochemical attributes may influence nebulised liposomal aerosols. Most notably, the aerosol droplet size and output rate are proportional to the concentration of the formulation.The residual liposome concentration is determined by the mean liposome size. The droplet size, nébulisation time, aerosol output, and residual liposome concentration are all significantly influenced by the particular jet nebuliser model selected for aerosol generation. The relative stability of different liposome formulations to nébulisation is also determined by a variety of factors, as revealed in chapter 4 of the thesis. The release of an entrapped marker, and the reduction in liposome size during nébulisation, is influenced by the nebuliser model, and also the liposome size and bilayer composition.Chapter 5 investigates the freeze drying of liposomes. The chapter concludes that liposomes for nébulisation may be freeze dried in the presence of a cryoprotectant, without influencing the aerosol produced following subsequent rehydration. Chapter 6 reveals that the droplet size produced from ultrasonic nebulised liposomes is relatively large, and the output inefficient from concentrated formulations. In addition, ultrasonic nébulisation is associated with similar liposome stability concerns as jet nébulisation.

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Section: Introductionmentioning

confidence: 99%