Sm. Saari et al., REGIONAL LUNG DEPOSITION AND CLEARANCE OF TC-99M-LABELED BECLOMETHASONE-DLPC LIPOSOMES IN MILD AND SEVERE ASTHMA, Chest, 113(6), 1998, pp. 1573-1579
Citations number
27
Categorie Soggetti
Respiratory System","Cardiac & Cardiovascular System
Objective: To compare the distribution and clearance of inhaled beclom
ethasone dipropionate (Bec)-dilauroylphosphatidylcholine (DLPC) liposo
mes in patients with mild and severe asthma. Design: A Tc-99m-labeled
Bec-DLPC suspension was delivered via a nebulizer (Aerotech II). Immed
iately after inhalation, anterior and posterior views of the lungs and
an anterior view of the oropharynx were measured by a large field gam
ma camera with the patient in a supine position. To evaluate the mucoc
iliary clearance of the inhaled liposomes, anterior and posterior lung
scans were repeated 1, 2, 4, and 24 h after the aerosol delivery. Pat
ients: Ten patients with mild asthma (FEV1 >80% of the predicted) and
10 patients with severe asthma (FEV1 <60% of the predicted) were inclu
ded in an open, parallel group study. Results: Clearance is more rapid
among patients with severe asthma (p<0.0001). At the 4-h measurement,
a mean of 82% (SD, 5.9) of the total pulmonary dose was detected in t
he lungs of patients with mild asthma while in those with severe asthm
a the figure was 69% (SD, 10.9). The ratio between central and periphe
ral deposition was significantly higher for patients with severe asthm
a than for those having a mild form of the disease; 1.07 (SD, 0.29) an
d 0.76 (SD, 0.07), respectively (p=0.008). Conclusions: Inhaled Bec-DL
PC liposomes were deposited more centrally in the lower airways of pat
ients with severe asthma than those having a milder form of the diseas
e. The clearance of Bec-DLPC liposomes is strikingly slow in both grou
ps of asthmatic patients. However, due to the more peripheral penetrat
ion of inhaled liposomes in patients with mild asthma, the clearance r
ate in this group was slower than in those with-severe asthma.