Lodelaben is a human neutrophil elastase inhibitor with an IC 50 and K i of 0.5 and 1.5 μM, respectively. In Vitro Lodelaben is a human neutrophil elastase inhibitor with an IC 50 and K i of 0.5 and 1.5 μM, respectively. Results indicate that the inhibition of human neutrophil elastase (HNE) by Lodelaben is non-competetive. Lodelaben is not inhibitory at 10 μM with the synthetic substrates or at 5 μM vith Azocoll. Pseudomonas aeruginosa elastase, a metallo-protease is not inhibited by Lodelaben. Cathepsin G activity, however, is inhibited by Lodelaben, with an IC 50 of approximately 2.5 μM, with Azocoll as substrate. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo The mean pulmonary artery pressures of the saline/vehicle and saline/Lodelaben groups are similar, 16.4±1.1 and 17.4±0.9 mm Hg, respectively. Although, mean pulmonary artery pressure in the monocrotaline/vehicle group is 27.5±0.8 mm Hg, treatment of monocrotaline rats with Lodelaben results in significantly lower values (21.00±1.6 mm Hg, p Animal administration Pathogen-free male Sprague-Dawley rats (250 to 300 g) are used. Half are assigned at random to be given a single subcutaneous injection of monocrotaline (60 mg/kg) and the other half receive an equal volume of 0.9% saline. Half of the rats in each group are further assigned at random to receive by gavage either Lodelaben ( 40 mg/kg/dose ) suspended in carboxymethylcellulose vehicle or an equal volume of vehicle only. The rats are gavaged twice daily starting 12 hours before and continuing for 8 days after the monocrotaline or saline injection to provide a \window\ around day 4. On day 13, after the monocrotaline or saline injection, the rats are anesthetized. Pressure measurements and cardiac output are recorded 48 hours later to allow sufficient time for recovery from the effects of anesthesia. The heart and lungs are then prepared for morphological assessments . aladdin has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:IC50: 0.5 μM (elastase), Ki: 1.5 μM (elastase)