A

Figure 6 Photograph of (A) Aeromist, (B) Respigard II, and (C) Pari LC Star nebulizers, the first two of which are used to deliver pentamidine.

Figure 6 Photograph of (A) Aeromist, (B) Respigard II, and (C) Pari LC Star nebulizers, the first two of which are used to deliver pentamidine.

97-99%, respectively [139]. The airflow rate was fixed at 8.3 and 9.1 L/min for the Bird and Acorn nebulizers, respectively. The nebulizers shown in Fig. 6 were assessed in their conventional orientation at different airflow rates [142]. The Respigard II that was operated in the range of airflow rates between 4.9 and 8.5 L/min produced an aerosol with a respirable fraction of 76-87%. The Aeromist that was operated at 7.6-11.8 L/min produced an aerosol with a respirable fraction of 91 -93%. Therefore, the operating conditions have only a slight effect on the respirable fraction of the aerosol. However, solution flowrate and airflow rate both significantly influence total output of these devices [139,142]. Low flowrates result in low total output. The implication of these observations is that high flowrates are more likely to result in a therapeutic effect.

A device using an alternative principle to that of the jet and ultrasonic nebulizers has been described but has not been adopted to any extent. The Babington nebulizer, shown in Fig. 7, uses a principle that was first devised for fuel atomization [143]. Liquid (for the purposes of this discussion, a drug solution) is supplied to the outer surface of a hollow sphere. A thin film forms over the entire surface of the sphere. Compressed air supplied to the interior of the sphere expands through a small rectangular orifice at the top of the dome. Fine liquid particles form as escaping air ruptures a portion of the liquid film

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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