Abstract:
Much attention has been drawn by inhalation as an effective route of drug administration
for the treatment of obstructive lung diseases. The human lung possesses a relatively large
surface area in the order of 126 m2 for drug absorption. Drugs are administered by
inhalation for two reasons, to increase the desired clinical effect of the drug by direct
application where that effect is needed and to reduce undesired side effects. An inhaler is a
device for administering vapor or volatilized medication by inhalation. Among the type of
inhalers, dry powder inhalers (DPI) are growing in popularity for being easy to use and
environmentally friendly. There are two kinds of DPls, single dose inhaler where the drug
is to be loaded whenever used and multi dose inhaler which could be used several times
without loading the drugs.
