The absorption and elimination of ICI 74,917 in man.

1 The pharmacokinetics of ICI 74,917 were studied in both asthmatic patients and normal volunteers. 2 The tritiated compound was administered to the lungs by inhalation from an aerosol and a bronchoscope, and by intravenous, oral and buccal routes. Radioactivity was measured in plasma, urine, faeces, sputum and exhaled air. 3 After bronchoscopic administration 63% of the available dose was absorbed; after aerosol administration 8% was absorbed from the lung and more than 50% swallowed. 5 Intravenous studies indicated that the drug is excreted in the bile and urine in the ratio 2:1. 5 Minimal oral and no buccal absorption occurred. 6 There was no evidence of tritium exchange or drug metabolism. 7 The mean terminal half-life following administration by all route was 16.1 hours. However, the majority of the dose was rapidly excreted. 8 Aerosol administration is the method of choice for the clinical use of ICI 74,917.