Table 1.

Activity-based and in silico approaches for drug repositioning.

Approaches	Pros	Cons
Activity-based	* No limitation for target-based and cell-based screening assays * Easy to validate screening hits * Lower rate of false positive hits during the screening	* Time and labor consuming * Requires an entire collection of existing drugs * Need to develop a screening assay
In silico	* Time and labor efficient * No need an entire collection of existing drugs * No need to develop a screening assay	* Limitation for target-based and cell based screenings (requires structural information of target proteins and drug-induced cell/disease phenotype information) * Higher rate of false positive hits during the screening