Therapeutic Application of Chloroquine in Clinical Trials for COVID-19

Divya RSJB Rana; Santosh Dulal

Mechanism of actions of chloroquine or hydroxychloroquine has been studied for both SARS-CoV and SARS-C0V-2. A study using Vero E6 cells found that treatment of the cells with chloroquine either before or after infection with SARS-CoV could prevent infection or treat the infected cells suggesting both prophylactic and therapeutic effect (8) . The study found chloroquine disturbed the biochemical maturation of the cellular receptor, angiotensin converting enzyme 2 (ACE2), for SARS-CoV, and increased the pH of intracellular virus-laden vesicles inhibiting the viral normal multiplication processes. The receptor for SARS-CoV-2 is also highly predicted of being ACE2 (1) . In vitro studies for SARS-CoV-2 also found chloroquine and hydroxychloroquine, a less-toxic derivative of chloroquine to be able to effectively inhibit viral growth (9) . They found the viral biological processes in the endosomes were affected by the anti-malarial agents. While the reported 50% effective concentration of the drugs are higher than the normal serum concentration reported in people taking these drugs, the concentrations in lungs and other vital organs are higher (10) . The most common side-effect of these are retinopathy and other side-effects precipitating due to higher concentrations of the compounds in blood.