**Conflict of interest**

*Drug Repurposing - Hypothesis, Molecular Aspects and Therapeutic Applications*

*Chemical structure of bimatoprost* **(26)***, phenytoin* **(27)***, tofacitinib* **(28)***, metformin* **(29)***, minoxidil* **(30)***,* 

Hall et al. used zebrafish neutrophil migration assay, for evaluation of the suppressive effect of 1280 approved drugs on recruitment of neutrophils; where drugs showing prominent anti-inflammatory activity were further tested in atopic dermatitis animal model, among them 11 drugs which was not reported previously

Chang et al. used in vivo model of chemically induced murine skin tumorigenesis to confirm the hypothesis of repositioning of beta blocker for treatment of skin cancer, since several studies showed that stress-related catecholamine hormone

Carvedilol **(32)**, when administrated orally and topically, prevented DMBAinduced epidermal hyperplasia, suggesting that it may serve as a new agent for protecting against skin cancer [50], which was supported by another study that demonstrated the preventive effect of carvedilol applied topically after UV exposure; so, it can be repositioned as prophylactic agent against skin inflammation and cancer [51]. Cannabidiol (CBD) **(33)** is a nonpsychoactive phytocannabinoid found in *Cannabis sativa*. It is approved recently for the treatment of seizures associated with two uncommon and serious forms of epilepsy, Dravet syndrome, and Lennox-Gastaut syndrome. Oláh et al. reported that CBD-treated human sebocytes and human skin organ in vitro showed strong antiproliferative, lipostatic, and antiinflammatory effects mediated by a plethora of receptors, ion channels, and other components of the endocannabinoid system [52]. These findings were confirmed later by clinical trial showing that CBD administrated as an ointment is an effective and noninvasive option for enhancing the quality of life in patients with some skin disorders, especially those with inflammatory background [53]. The chemical

Drug repositioning is an important strategy to maximize the benefits from already approved drugs; it will not only contribute to reduction of time and cost

*niclosamide* **(31)***, carvedilol* **(32)***, and cannabidiol (CBD)* **(33)***.*

expression can affect tumor progression [49].

structure of compounds **(26–33)** is depicted in **Figure 8**.

**3. Concluding remarks and future perspective**

as anti-inflammatory agent [48].

**56**

**Figure 8.**

The authors declare no conflict of interest.
