Hydroxychloroquine
Hydroxychloroquine (HCQ) sulfate, a derivative of Chloroquine (CQ), was first synthesized in 1946 by inserting a hydroxyl group into CQ and was shown to be much less (~40%) toxic than CQ in animals[13]. More significantly, HCQ is now commonly available for the treatment of autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. Since CQ and HCQ share similar chemical structures and mechanisms to serve as a weak base and immune-modulator, the idea that HCQ may be a potent candidate for treating SARS-CoV-2 infection is simple to conjure up [28]. As of 23 February 2020, seven registries of clinical trials have been listed in the Chinese Clinical Trial Registry (http:/www.chictr.org.cn) to use HCQ for COVID-19 diagnosis. The experimental evidence still lacks whether HCQ is as effective as CQ in the treatment of SARS-CoV-2 infection [29]. Hydroxychloroquine on viruses is generally the same as chloroquine because the action mechanism of these two molecules is similar, so researchers are more inclined to administer hydroxychloroquine for long periods, which will therefore be the first option in the treatment of SARS-CoV-2. Hydroxychloroquine performed pharmacology based pharmacokinetics (PBPK) modelling to evaluate its activity in the lung. In vitro analyses in Vero cells demonstrated that the potency of hydroxychloroquine (EC50 of 0.72 μM) was greater than that of Chloroquine against 2019-nCoV.