1. Center for Pharmaceutical Informatics, Department of Pharmacy, Uppsala University, Uppsala Biomedical Center, P.O. Box 580, SE-751 23 Uppsala, Sweden, Department of Medicinal Chemistry, AstraZeneca R&D, SE−151 85 Södertälje, Sweden, and Department of Chemistry, Medicinal Chemistry, Göteborg University, SE−412 96 Göteborg, Sweden