Pharmacokinetics of liposomal aerosolized cyclosporine A for pulmonary immunosuppression

Background. The results of pulmonary transplantation are compromised by acu te and chronic rejection. We hypothesized that a liposomal form of aerosoli zed cyclosporine A (CsA) would he selectively deposited and concentrated in the lungs. The theoretical advantage of this therapy is selective pulmonar y immunosuppression with prolonged utilization. Methods. Eighteen dogs were endotracheally intubated; aerosolized liposomal CsA was administered for 15 min. CsA levels were measured in whole blood, lung trachea, heart, kidney, liver, and spleen at various times after treat ment. Results. The lung rapidly absorbs aerosolized liposomal CsA; other organs h ave much lower concentrations. The retention of pulmonary CsA delivered by liposome aerosol is approximately 120 min in this model. Conclusions. Aerosolized liposomal CsA is selectively deposited and concent rated in the lungs; other organs absorb less CsA. (C) 1999 by The Society o f Thoracic Surgeons.