Drug Repurposing for COVID-19 from FDA Approved and Experiment Stage Drugs by in Silico Methods with SARS CoV-2 Spike Protein

E-pharmacophore based virtual screening of DrugBank database is carried out to identify candidate drugs for repurposing. The dug molecules were screened based on the pharmacophore generated and filtered through the 6000 drug molecule to obtain better 2000 of them. This filtered drug molecules further screened via structure based approach, involving molecular docking at different precisions. From the large database seven drug lead molecules were selected as hits and their binding energy with the spike protein were calculated. Cladribine, Clofarabine, Fludarabine from approved category and 7-methyl-guanosine-5'-triphosphate-5'-guanosine, Adenosine-2'-5'-Diphosphate, 8-Bromo-Adenosine-5'-Monophosphate, Alpha-Methylene Adenosine Monophosphate in the experimental category were found to be potent inhibitors of SARS CoV-2 spike protein to repurpose as drugs for COVID-19.