Medical and Pharmaceutical Aerosols - Aerosols: Measurement, Dosimetry, and Health Effects - page 20

TABLE 1.5 (continued)
Drugs Delivered by the Inhalation Route

Product Active Dose/Inhalation Dose/Day

Pulmicort respules Budesonide

Suspension

0.25 mg/2 mL
0.5 mg/2 mL

1 nebulization once or
twice for a maximum of
0.5 mg

Pulmozyme
solution

Dornase alfa 1.0 mg/mL

(2.5 mL)

1 nebulization once (1 mg)

Source: Murray, L. and Kelly, G.L., Physicians' Desk Reference , Medical Economics Company, Inc.,
Montvale, NJ, 2010.
a Doses in MDIs and DPIs are described from the mouthpiece.
b Nebulizations usually take between 15 and 30 min in average if used with the nebulizer and compressor
recommended by manufacturer observing the recommended parameters.

medications are administered by either MDI or DPI. Table 1.5 shows some commercial preparations
to be delivered by nebulization. Doses range from a few milligrams, to be used at home, to several
hundred milligrams or even grams when they are used in hospital settings. Nebulizers are more
effective generators of small particles than MDIs and DPIs. 100 Recent nebulizer designs provide
increased eficiency of deliver by gauging the patient's breathing and delivering aerosol only during
inhalation. Other systems achieve increased delivery eficiency by collecting the aerosol generated
during exhalation in a reservoir. Nebulizer reservoirs increase the delivery rate of nebulized medi-
cations by conserving the aerosol generated during exhalation and making it available to the patient
during the next inhalation. 195 The development of medications for nebulization should include the
speciication and testing of a nebulizer and the compression source that is ixed by prescription
along with the medication. Alterations of nebulizer/compression source must be carefully consid-
ered at the physician level as such alterations could signiicantly change the dose received by the
patient even if the same nebulizer charge dose is used. 114

1.6 CONCLUDING REMARKS
Aerosols have a long history in the medical and pharmaceutical ields, and research in this area
will continue to push the boundaries of drug delivery for several decades to come. While most
aerosol therapeutics currently on the market are locally acting, systemic drug delivery via the lungs
has great potential. Current research, other than improving present designs for higher eficiency,
includes protein delivery in order to bypass the oral and intravenous routes, avoiding irst-pass
metabolism of the therapeutic and allowing higher patient compliance and comfort.
The three main types of aerosol delivery systems are pMDIs, DPIs, and nebulizers, each
of which has its own pros and cons. While nebulizers are typically used in a hospital setting,
pMDIs and DPIs are portable devices that are able to keep up with the active lifestyle of the
patient. Research into portable nebulizers is still being conducted due to their increased eficacy.
However, there is no one universal method for pulmonary delivery, and each drug must be inves-
tigated to determine the appropriate delivery method by balancing cost, performance, and patient
compliance. Before a formulation can successfully be implemented via one of these devices,
it has to be characterized in numerous ways to determine particulate size, cohesion, adhesion,
dispersion, deposition, and dosimetry. The overall eficiency of DPIs and pMDIs is still fairly
low; future devices will need to have much higher RFs in order to deliver expensive drugs in a
cost-effective manner.