1. The Robert Robinson Laboratories, Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K., AstraZeneca UK Ltd., Drug Metabolism and Pharmacokinetics Department, Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG, U.K., Analytical Unit, St. George's Hospital Medical School, London, U.K., and William Harvey Research Institute, Barts and the London, Queen Mary School of Medicine and Dentistry, Charterhouse Square, London EC1M 6BQ, U.K.