Nebulization aerosoling

The rf energy is provided to the electrons, so that the rf field accelerates the electrons, which ionize the noble gas (e.g., argon) used for transporting the nebulized aerosols via electron ionization... 

The APEX system (Element Scientific Inc., Omaha) as an improved Aridus nebulizer was introduced for ICP-MS in 2004 for more effective solution introduction at flow rates from 20-400 p,lmin-1.88 In this solution introduction system (see Figure 5.15), a microflow PFA nebulizer is combined with a heated cyclonic spray chamber followed by cooling of the nebulized aerosol in a condenser loop and using a multipass condenser cooled by a Peltier element. The APEX solution introduction system results in a significant increase of sensitivity (by a factor of ten in comparison to a standard nebulizer spray chamber arrangement) and a decreasing polyatomic formation rate.89... 

Later, Lizio et al. [78] used a new aerosol delivery system (ASTA-ADS) to investigate the pulmonary absorption and tolerability of four different cetrorelix formulations delivered as nebulized aerosols to orotracheally cannulated rats. After only 5 min exposure to the cetrorelix aerosol, serum testosterone concentrations were reduced to subnormal levels over a 24-h period. After dose adjustment (dose delivered minus exhaled amount), the bioavailabilities for pulmonary delivery ranged from 48.4 27.0% to 77.4 44.0% compared to IV administration. In addition, the lung function parameters did not reveal any formulation-related changes. Overall, the results of cetrorelix aerosol administration compared well with those obtained with intratracheal instillation of cetrorelix solution [77]. 

Fig. 1 Proposed ultrasonic nebulizer aerosolization mechanisms. (A) Cavitation bubble formation at low frequency (B) capillary-wave formation at high frequency. (From Ref...

Numerous investigators have compared the aerosol droplet size of nebulized aerosols from ultrasonic and air-jet devices. " Because droplet size is inversely proportional to the acoustic frequency, smaller droplets are generated from ultrasonic devices with higher frequencies. Ultrasonic nebulizers with high operating frequencies (2-3 MHz) are capable of... 

For aerosols in which the particle velocity is determined by the inspiratory flow rate and the particle size is not sensitive to it, it is expected that the increase in flow rate increases the upper and central airway deposition. For example, Ryan et al. [90] found that fast vital capacity inhalation resulted in a greater proportion of nebulizer aerosol depositing in the central airways than when the aerosol was inhaled slowly. However, the dependence on the inspiratory flow rate becomes more subtle when the particles have intrinsic velocity (such as droplets generated by propellant-driven metered-dose inhalers that need to be entrained into the inhaled air) or the particle size is inspiratory flow dependent (as in the case of passive dry powder inhalers). 

Nebulized aerosol is introduced to the patient by compressed air, either from a constant source or from a device known as intermittent positive-pressure ventilator. Nebulized aerosols rely less on the patient s own breathing pattern. Under some circumstances the dose administered to the patient by nebulizer is inconsistent or unpredictable. In a hospital setting, the aerosol administration can be supervised by qualified individuals. Home administration is not always supervised, and there is, therefore, a potential for misuse. 

Cromolyn. One would not ordinarily consider cromolyn to have any action other than local, but higher-cromolyn blood correlates with better clinical efficacy [121]. Delivery methods affect cromolyn delivery. Disodium cromoglycate (20 mg) delivered to normal subjects via nebulized aerosol as nebulizer solution only, nebulizer solution with saline, or nebulizer solution plus a beta 2 agonist yielded, respectively, peak levels of 8.8, 17.2, or 24.5ng/mL [122]. The clinical relevance of these data is not clear. 

Ten years later, Taylor et al. [84] published a study on the effects of Upo-some encapsulation on the pharmacokinetics in humans of sodium cromoglycate, a water-soluble antiasthmatic/antiallergenic compound. The dmg was formulated in dipalmitoylphosphatidylcholine/cholesterol (DPPC/CH) (1 1 molar ratio) liposomes and administered as a nebulized aerosol. The researchers demonstrated that, compared with drug administered in solution, the liposomally encapsulated dmg achieved a lower C ax and prolonged plasma half-life, indicating that the liposomes were controlling dmg delivery. 

Urine (Matusiewicz and Barnes, 1985) - NIOSH-NBS freeze dried urine is reconstituted in water. 50 nL samples are determined. Instrumentation Plasma-Therm model 5000D ICP-AES spectrometer. Instrumentation Laboratory FASTAC II pneumatic nebulizer/aerosol delivery system to deliver sample to a model IL655 furnace for graphite furnace vaporization at 2500°C. Argon plasma, 40.68 MHz, A = 231.60 nm, pyrolytically coated graphite tube with platform. Detection limit 0.9 hqIL (45 pg Ni) by peak area, 12 /peak height. Urine reference material found 1.05 mg/L (RSD 2.1%), expected 1.01 0.11 mg/L. 

The mast cell stabilizers are used in combination widi other drugs in the treatment of asdima and odier allergic disorders, including allergic rhinitis (nasal solution), and in the prevention of exercise-induced bron-chospasm. When die mast cell stabilizers are used in conjunction widi odier antiasdima dni, a reduction in dosage of die dni may be possible after using die mast cell stabilizer for 3 or 4 weeks. These dni may be given by nebulization, aerosol spray, or as an oral concentrate... 

The only U.S. FDA-approved DNase product, Dornase alpha (inhalation solution), has been developed as a therapeutic agent for the management of CF. The product is supplied in single-use ampules delivering 2.5 ml of a sterile, clear, colorless solution containing 1.0 mg/ml of dornase alpha with no preservative. Administration is by nebulizer aerosol delivery systems. 

The inhalation of nebulized aerosols was advertised as beneficial for many ailments. The Sales-Girons device was advised for pharyngitis, laryngitis, bronchitis, pain, catarrh, asthma, tuberculosis, and sleeplessness (12). The liquids and substances inhaled varied widely and included mineral water containing sulfur, iodine, and chlorine sedatives antiseptics and belladonna. In 1882, Yeo (3) prescribed the use of a mixture of creosote, carbolic acid, eucalyptus, or turpentine with equal parts of spirit and chloroform in his oronasal inhaler. The Yeo inhaler, which is poorly described, is probably more of a vaporizer than an early nebulizer. Earlier, in 1878, Lee (3) performed antiseptic experiments using a jet of steam containing a mixture of phenol and water. Iodoform, iodine, thymol, and terebene were also used (3). 

Palmer F, Kingsbury SS. Particle size in nebulized aerosols. Am J Pharm 1952 124 112-124. 

There are only two experimental strategies that have the potential to yield reliable predictive results for nebulized aerosols. The first is to measure the droplets in their fully hydrated state. This can be done either immediately as they exit the mouthpiece, using a real-time sizing instrument, or by reducing the evaporation kinetics sufficiently to allow measurement downstream with an offline techniqne snch as inertial cascade impaction. The second is to completely dry the aerosol, size the dry particles, and then calculate back to obtain the original size distribntion. Measuring the aerosol at intermediate hydration states between these two extremes is obviously problematic because the hydration state would have to be measured in order to correct the size distribution back to the original inhaled size. 

Figure 8 Correlation between the volume median diameter of a nebulized aerosol, measured by laser diffraction, and thoracic deposition expressed as percent of total body deposition. The 95% confidence intervals represent the variability between volnnteer groups and not true intersubject variability. (From Ref. 3.)...

Portstendorfer J, Gebhart J, Robig G. Effect of evaporation on the size distribution of nebulized aerosols. J Aerosol Sci 1977 8 371-380. 

Thomas SHL, O Doherty Ml, Page CJ, Nunan TO. Variability in the measurement of nebulized aerosol deposition in man. Clin Sci 1991 81 767-775. 

Although the lung dose was higher for the ultrasonicaUy nebulized aerosol, the bioavailability of insulin, determined from area under the insulin concentration-time curves, was lower when compared to the jet nebulizer. The efficacy of the ultrasonicaUy nebulized aerosol in terms of lowering blood glucose levels was also less, averaging only a 40- 5% decrease compared to a 50-55% decrease with the jet nebulized aerosol. 

Newman SP, PeUow PGD, Clarke SW. Droplet size distributions of nebulized aerosols for inhalation therapy. Chn Phys Physiol Meas 1986 7 139-146. 

Finlay WH, Smaldone GC. Editorial hygroscopic behavior of nebulized aerosols not as important as we thought J Aerosol Med 1998 11 193-195. 

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