Inhalation effort

Figure 3.5. The effect of external resistance and clinical conditions on the pressure drop generated at maximum inhalation effort. The area between the dashed lines represents the 95% confidence interval.

Energy input is required to extract the powder from its packaging, generate the fine particle cloud, and dilute it with air. Historically, this energy comes from the patient s inhalation effort (Table 2). In some cases, the energy for extracting/metering the powder comes from the mechanical manipulation of the device by... 

The inhalation flow affects pulmonary deposition but not the properties of the aerosol delivered by a pMDI Conversely, the intrinsic properties of the aerosol emitted from a DPI—a breath-actuated device—are highly dependent on the inhalation effort of the patient (83), and the inhalation flow must always be sufficiently high to produce an aerosol containing the optimal amount of fine particles (72,84)... 

The discovery of the utility of the bis-chromone carboxylic acid derivative cromolyn sodium in the treatment of asthma and related allergies has led to an intensive, and thus far not very fruitful, effort to discover analogues which would show oral activity in contrast to the lead which must be administered by inhalation. Preparation of a typical analogue, proxicromil (63), starts with the O-allylated phenol 57. Claisen rearrangement leads to the corresponding C-allylated product 58. 

Although government officials attempted to educate the public and military personnel about atomic civil defense, in retrospect these efforts seem hopelessly naive if not intentionally misleading. Army training films advised soldiers to keep their mouths closed while obser"ving atomic test blasts in order to not inhale radioactive flying dirt. Civil defense films used a friendly animated turtle to teach schoolchildren to duck and cover during a nuclear attack—that is, duck under their desks and cover their heads. Such measures, of course, would have offered pitiful protection to those in the blast zone. 

The oral reference dose (RfD) for trichloroethylene is currently imder review by an EPA workgroup (IRIS 1996). No inhalation reference concentration (RfC) has been derived (IRIS 1996). The National Center for Environmental Assessment, EPA has begun an effort to reassess the health risks associated with trichloroethylene. 

Since LSD would be released as an aerosol if used in a military setting, we devoted considerable effort to estimating its relative potency by the inhalation route. Two forms of the drug the maleate salt (black circles) and the free base (white) were compared (Fig. 95). There appeared to be no difference between the two salts in their effects on NF performance. 

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