Nasal deposition

Breathing pattern/nasal deposition Same as Harley (1984). 

There are only scant data on nasal deposition. The available studies reported utilized micron sized particles and the dominant mode of deposition is impaction. This is not the case for the particles considered here and diffusion and turbulent diffusion are the mechanisms of interest. George and... 

Breslin (1969) measured nasal deposition for both the attached and unattached fraction of radon daughters in a laboratory atmosphere and found it to be about 1% for the attached and 60% for the unattached fraction. The size characteristics of the unattached fraction is assumed to be that found by Knutson et al. (1983) for older air of 0.005 pm (D=0.0025 cm2/sec). No data are available for nasal deposition of the small sized kerosene heater particles, 0.030 pm, and the value for the attached radon daughters of 1.3% is used. 

Particle diameter 0.17 pm (AMD) for Attached Daughters Nasal Deposition 1.3% for Attached and 60% for Unattached Daughters Alpha dose to cells at 22 pm depth below epithelial surface Twenty percent alveolar deposition prior to expiration... 

Powder Properties Affecting Nasal Deposition and Drug Delivery... 

This chapter will discuss some of the practical issues to be aware of when performing radiolabeled deposition and clearance studies (Table 2). The considerations apply to both in vivo studies in man and, in animal models and, to some extent, in in vitro models. Nasal deposition and clearance studies and tracheal transport measurements will not be discussed in detail, although it should be understood that the importance of a valid radiolabeled test aerosol is key to the successful interpretation of the deposition data for both nasal and lung studies [54,55]. 

Dallas CE, Theiss JC, Harris RB, et al. 1985. Effect of subchronic formaldehyde inhalation on minute volume and nasal deposition in Sprague-Dawley rats. J Toxicol Environ Health 16 553-564. 

Droplet Cparticle size Suitable for nasal deposition Measure droplet size distribution... 

Becquemin and co-workers (28) have studied nasal deposition of particles in adults and in children older and younger than 12 years of age. Total resistance in the nose was about twice that of adults for the children. The percentage deposition was equal or higher in adults than in children, for both resting ventilation and moderate exercise ventilation. 

There are several approaches to characterize nasal deposition by mathematical (120,122)orby empirical models (163,165-168,173,184,188,189). For particles of 1 (Am or larger, Rudolf et al. (168) estimated inspiratory particle collection efficiency of the nose ( et-n) by... 

Deposition of particles of the thermodynamic size range has not been studied extensively in humans. Cheng and co-workers (185) measured deposition efficiencies for 4-, 8-, 20-, and 150-nm particles in ten healthy adult, male volunteers. For nose-in mouth-out breathing at flow rates of 333 cm s, deposition fractions for these particle sizes were 36.7 10.6 (mean SD), 21.2 8.9, 11.1 7.7, and 5.2 3.8%. However, because expiratory deposition in the mouth is not negligible for particles in the thermodynamic domain, these values overestimate nasal deposition. The large SD values indicate that intersubject deposition variability is notable in the thermodynamic domain. Mean nasal deposition, as de-... 

Expiratory deposition is again eonsidered to be negligible in comparison with inspiratory deposition (163,184). Figure 9 shows deposition data predieted by the model for breathing eonditions during rest and exercise. The model assumes a eonstant respiratoiy flow rate Q, but takes into account that the colleetion efficieney decreases with inereasing tidal volume Ft. It shows that oral deposition is less dependent on flow rate than is nasal deposition, as Q is weighted by a power exponent of 0.6. Therefore, the aerodynamic particle diameter is the main... 

Scott WR, Taulbee DB, Yu CP. Theoretical study of nasal deposition. Bull Math Biol 1978 40 581-603. 

Swift DL, Strong JC. Nasal deposition of ultrafine Po aerosols in human subjects. J Aerosol Sci 1996 27 1125-1132. 

Zhang L, Yuh CP. Empirical equations for nasal deposition of inhaled particles in small laboratory animals and humans. Aerosol Sci Teehnol 1993 19 51-56. Gradon L, Yu CP. Diffusional particle deposition in the human nose and mouth. Aerosol Sci Teehnol 1989 11 213-220. 

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