D668–D672 Nucleic Acids Research, 2006, Vol. 34, Database issue doi:10.1093/nar/gkj067 DrugBank: a comprehensive resource for in silico drug discovery and exploration David S. Wishart*, Craig Knox, An Chi Guo, Savita Shrivastava, Murtaza Hassanali, Paul Stothard, Zhan Chang and Jennifer Woolsey Department of Computing Science and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E8 Received August 14, 2005; Revised and Accepted October 8, 2005 ABSTRACT DrugBank is a unique bioinformatics/cheminformat- ics resource that combines detailed drug (i.e. chem- ical) data with comprehensive drug target (i.e. protein) information. The database contains .4100 drug ent- ries including .800 FDA approved small molecule and biotech drugs as well as .3200 experimental drugs. Additionally, .14 000 protein or drug target sequences are linked to these drug entries. Each DrugCard entry contains .80 data fields with half of the information being devoted to drug/chemical data and the other half devoted to drug target or protein data. Many data fields are hyperlinked to other data- bases (KEGG, PubChem, ChEBI, PDB, Swiss-Prot and GenBank) and a variety of structure viewing applets. The database is fully searchable supporting extensive text, sequence, chemical structure and relational query searches. Potential applications of DrugBank include in silico drug target discovery, drug design, drug docking or screening, drug metabolism predic- tion, drug interaction prediction and general pharma- ceutical education. DrugBank is available at http:// redpoll.pharmacy.ualberta.ca/drugbank/. INTRODUCTION Until the 1980s, most of our knowledge about drugs, drug mechanisms and drug receptors could ﬁt in a few encyclopedic books and a couple dozen schematic ﬁgures. However, with the recent explosion in biological and chemical knowledge, this is no longer the case. There is simply too much data (images, models, structures and sequences) from too many sources. Unfortunately, most of this information still resides in textbooks or print journals. The limited drug or drug recep- tor data that is electronically available is either inaccessible (except through expensive subscriptions), inadequate or widely scattered among many different public databases. This state of affairs largely reﬂects the ‘two solitudes’ of cheminformatics and bioinformatics. Neither discipline has really tried to integrate with the other. As a consequence, the wealth of electronic sequence/structure data that exists today has never been well linked to the enormous body of drug or chemical knowledge that has accumulated over the past half century. Recently, some notable efforts have been made to partially overcome this ‘informatics gap’. The Therapeutic Target Database or TTD is one such example (1). This very useful web-based resource contains linked lists of names for >1100 small molecule drugs and drug targets (i.e. proteins). In addi- tion to the TTD, a number of more comprehensive small molecule databases have also emerged including KEGG (2), ChEBI (3) and PubChem (http://pubchem.ncbi.nlm.nih. gov/). Each contains tens of thousands of chemical entries—including hundreds of small molecule drugs. All three databases provide names, synonyms, images, structure ﬁles and hyperlinks to other databases. Furthermore, both KEGG and PubChem support structure similarity searches. Unfortunately, these databases were not speciﬁcally designed to be drug databases, and so they do not provide speciﬁc pharmaceutical information or links to speciﬁc drug targets (i.e. sequences). Furthermore, because these databases were designed to be synoptic (containing <15 ﬁelds per compound entry) they do not provide a comprehensive molecular sum- mary of any given drug or its corresponding protein target. More specialized drug databases such as PharmGKB (4) or on- line pharmaceutical encyclopedias such as RxList (5) tend to offer much more detailed clinical information about many drugs (their pharmacology, metabolism and indications) but they were not designed to contain structural, chemical or physico-chemical information. Instead their data content is targeted more towards pharmacists, physicians or consumers. Ideally, what is needed is something that combines the strengths of, say, PharmGKB, PubChem and Swiss-Prot to *To whom correspondence should be addressed. Tel: +1 780 492 0383; Fax: +1 780 492 1071; Email: david.wishart@ualberta.ca The Author 2006. Published by Oxford University Press. All rights reserved. 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