DISTRIBUTION STUDIES OF LIPOSOME-ENCAPSULATED GLUTATHIONE ADMINISTERED TO THE LUNG

To test the feasibility of using liposomes for the pulmonary delivery of glutathione, we compared the distribution of free and liposome-encapsulated glutathione after intratracheal instillation of the 3H-labelled tripeptide to rats. Free glutathione rapidly left the lung and entered the circulation. Liposomally delivered glutathione remained in the lung for a prolonged period, most likely by remaining in encapsulated form, and entered the bloodstream only after release from the liposomes. Excretion of 3H into the urine after liposomally delivered glutathione was associated with free glutathione or its degradation products. Glutathione from liposomes instilled into the trachea was not distributed evenly among different lobes of the lung; however, the variation was not greater than 4-fold. These results demonstrate that exogenously supplied glutathione can be confined to the lung by means of a liposomal delivery system. © 1990.