Table 2.

Various approaches to drug repurposing.

Sl.no	Approaches to drug repurposing	Description
1	In silico drug repurposing	Database consists of information gathered from research, clinical trials, reports of label uses, and other published datas
1.1.	Text mining approach	Mine the information and identify the connections or relationships
1.2	Cluster approaches	Can discover novel drug-target or drug-disease relationships based on the concept that biological entities and network of same module have identical characters.
1.3	Propagation approach	Useful in discovering disease-genes, disease-disease, and target- disease relationships based on the concept that information transferred from source node to network nodes and to various sub network nodes.
1.4	Semantics approach	Biological entity relationships are found out from data in medical databases and a semantic network is built also based on existing ontology network and algorithms are developed to discover relationship in the network.
1.5	Databases and resources	Maintained with the purpose of storing, managing and retrieving information. Different types of databases used include pharmacological databases, chemical databases, proteomics databases
2	Biological approaches	Models are  developed based on understanding of molecular level pathways and simulate physiological environment of target proteins
3	Experimental approaches	Based on experimentation including targets screening, cell assay, animal model and clinical trials
4	Mixed approaches	It is a mixture of computational observation, biological experiments and clinical testing.
5	Knowledge-based  repurposing	Based on the knowledge of researchers and doctors and their capability and skill to interpret observations.