Aerosol delivery advantages

Inertial impaction is the method of choice for evaluating particle or droplet size delivery from pharmaceutical aerosol systems. This method lends itself readily to theoretical analysis, ft has been evaluated in general terms [39] and for specific impactors [40]. Inertial impaction employs Stokes law to determine aerodynamic diameter of particles being evaluated. This has the advantage of incorporating shape and density effects into a single term. 

Even though all three reactors share the same precursor delivery system, each tool offers specific advantages. For example, a cold-wall reactor (reactor B) helps prevent decomposition of the precursor before it reaches the substrate. A pulsed aerosol injection system at low pressure (reactor C) allows the film to grow under better-defined conditions than in a continuous process (reactor A) because of the minimization of undesirable transient effects caused by the high volatility of the solvents used.46 A more detailed description of each of the conditions for film growth, including reactor type, precursor type, delivery method, deposition temperature, growth time, and other parameters are summarized in Table 6.2. Depositions were done on bare and Mo-coated... 

Uneontrolled Advantages Deviee is simpler, no feed-baek systems are required to monitor the patient Violent aerosol generation proeesses are allowable, permitting the delivery of large amounts of energy to the powder in a short period of time... 

Pulmonary administration of PNAs has great potential for the same reasons that pulmonary protein and peptide delivery have been successful. Predominantly, the distance for transport and ease of administration of agents are the advantages of pulmonary delivery, but the formulation of labile molecules for eventual pulmonary administration as lipid-based aerosols may be problematic. 

The aerosol cloud should consist largely of particles of less than 5 pm in size. Fine aerosols are necessary for delivery to the lung periphery if this is the site of action or if systemic delivery is the objective. The ability to vary and then control the mean particle size distribution of the aerosol would be an added advantage for targeting deposition within different regions of the respiratory tract. 

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