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The deposition and clearance of liposome entrapped 99mTc-DTPA in the human respiratory tract

1994; Elsevier BV; Volume: 102; Issue: 1-3 Linguagem: Inglês

10.1016/0378-5173(94)90051-5

1873-3476

S. A. Barker, Kevin Taylor, Michael D. Short,

Medical Imaging and Pathology Studies

The size characteristics of aerosols produced by nebulising liposomes from five jet nebulisers have been investigated. The size and size distribution of the aerosols was determined by the design of the nebuliser and the gas flow rate employed to drive the nebuliser, rather than on the properties of the liposome preparations themselves. The clearance of inhaled dipalmitoylphosphatidylcholine/cholesterol liposomes containing the aqueous phase marker 99mTc-DTPA was studied by gamma-scintigraphy following inhalation by three healthy volunteers. Approx. 45% of originally deposited radioactivity remained in the lungs after 24 h. This represents the fraction of the radiolabel remaining in intact alveolar-deposited vesicles, since free 99mTc-DTPA was removed from the airways with a half-life of 75 min.