Regional lung deposition and clearance of 99mTc-labeled beclomethasone-DLPC liposomes in mild and severe asthma.
OBJECTIVE
To compare the distribution and clearance of inhaled beclomethasone dipropionate (Bec)-dilauroylphosphatidylcholine (DLPC) liposomes in patients with mild and severe asthma.


METHODS
A 99mTc-labeled Bec-DLPC suspension was delivered via a nebulizer (Aerotech II). Immediately after inhalation, anterior and posterior views of the lungs and an anterior view of the oropharynx were measured by a large field gamma camera with the patient in a supine position. To evaluate the mucociliary clearance of the inhaled liposomes, anterior and posterior lung scans were repeated 1, 2, 4, and 24 h after the aerosol delivery.


METHODS
Ten patients with mild asthma (FEV1 >80% of the predicted) and 10 patients with severe asthma (FEV1 <60% of the predicted) were included 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 the lungs of patients with mild asthma while in those with severe asthma the figure was 69% (SD, 10.9). The ratio between central and peripheral deposition was significantly higher for patients with severe asthma than for those having a mild form of the disease; 1.07 (SD, 0.29) and 0.76 (SD, 0.07), respectively (p=0.008).


CONCLUSIONS
Inhaled Bec-DLPC liposomes were deposited more centrally in the lower airways of patients with severe asthma than those having a milder form of the disease. The clearance of Bec-DLPC liposomes is strikingly slow in both groups of asthmatic patients. However, due to the more peripheral penetration of inhaled liposomes in patients with mild asthma, the clearance rate in this group was slower than in those with severe asthma.
Saari
S M
SM
Department of Clinical Physiology and Nuclear Medicine, Tampere University Hospital, University of Tampere Medical School, Finland.
Vidgren
M T
MT
Koskinen
M O
MO
Turjanmaa
V M
VM
Waldrep
J C
JC
Nieminen
M M
MM
D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001249:Asthma / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D001507:Beclomethasone / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004337:Drug Carriers; D005260:Female; D005541:Forced Expiratory Volume; D015902:Gamma Cameras; D006801:Humans; D008081:Liposomes; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D010713:Phosphatidylcholines; D011877:Radionuclide Imaging; D013667:Technetium
D018927:Anti-Asthmatic Agents; D004337:Drug Carriers; D008081:Liposomes; D010713:Phosphatidylcholines; C015153:1,2-dilauroylphosphatidylcholine; D013667:Technetium; D001507:Beclomethasone