First-principles DFT investigations of the vibrational spectra of chloro-quine and hydroxychloroquine

Since the COVID-19 pandemic began, two drugs, chloroquine (CQ) and hydroxychloroquine (HCQ), have received renewed attention. Using the density functional theory method in the CASTEP and DMol3 packages, we calculated both molecules’ infrared spectra and the partial phonon density of states of the hydroxyl group to identify the origin of the differences between the two spectra. Some characteristic vibrational modes of the hydroxyl group in HCQ were analysed individually. We also compared their Fukui functions and found that the oxygen atom in HCQ possesses electrophilic properties. This finding may be related to the large difference in toxicity between these two drugs. The method herein presents a new pathway to investigate organic molecules from the view of physics.

Factors associated with prolonged viral shedding and impact of Lopinavir/Ritonavir treatment in patients with SARS-CoV-2 infection (preprint)

Background: The duration of viral shedding is central to guide decisions around isolation precautions and antiviral treatment. However, studies about risk factors associated with prolonged SARS-CoV-2 shedding and the potential impact of Lopinavir/Ritonavir (LPV/r) treatment remain scarce. Methods: In this retrospective study, data were collected from all SARS-CoV-2 infected patients who were admitted to isolation wards and had RT-PCR conversion at the NO.3 People's hospital of Hubei province between 31 January and 09 March 2020. We compared clinical features and SARS-CoV-2 RNA shedding between patients with LPV/r treatment and those without. Logistic regression analysis was employed to evaluate risk factors associated with prolonged viral shedding. Results: Of 120 patients, the median age was 52 years, 54 (45%) were male and 78 (65%) received LPV/r treatment. The median duration of SARS-CoV-2 RNA detection from symptom onset was 23 days (IQR, 18-32 days). Older age (odd ratio [OR] 1.03, 95% confidence interval [CI] 1.00-1.05, p=0.03) and lack of LPV/r treatment (OR 2.42, 95% CI 1.10-5.36, p=0.029) were independent risk factors for prolonged SARS-CoV-2 RNA shedding in multivariate logistic regression analysis. The median duration of viral shedding was shorter in the LPV/r treatment group (n=78) than that in no LPV/r treatment group (n=42) (median, 22 days vs. 28.5 days, p=0.02). Only earlier administration of LPV/r treatment ([≤]10 days from symptom onset) could shorten the duration of viral shedding. Conclusions: Older age and lack of LPV/r treatment were independently associated with prolonged SARS-CoV-2 RNA shedding in patients with COVID-19. Earlier administration of LPV/r treatment could shorten viral shedding.