Recent Clinical and Preclinical Studies of Hydroxychloroquine on RNA Viruses and Chronic Diseases: A Systematic Review

The rapid spread of the new Coronavirus Disease 2019 (COVID-19) has actually become the newest challenge for the healthcare system since, to date, there is not an effective treatment. Among all drugs tested, Hydroxychloroquine (HCQ) has attracted significant attention. This systematic review aims to analyze preclinical and clinical studies on HCQ potential use in viral infection and chronic diseases. A systematic search of Scopus and PubMed databases was performed to identify clinical and preclinical studies on this argument; 2463 papers were identified and 133 studies were included. Regarding HCQ activity against COVID-19, it was noticed that despite the first data were promising, the latest outcomes highlighted the ineffectiveness of HCQ in the treatment of viral infection. Several trials have seen that HCQ administration did not improve severe illness and did not prevent the infection outbreak after virus exposure. By contrast, HCQ arises as a first-line treatment in managing autoimmune diseases such as rheumatoid arthritis, lupus erythematosus, and Sjögren syndrome. It also improves glucose and lipid homeostasis and reveals significant antibacterial activity.     

Nanomedicine Reformulation of Chloroquine and Hydroxychloroquine

The chloroquine family of antimalarials has a long history of use, spanning many decades. Despite this extensive clinical experience, novel applications, including use in autoimmune disorders, infectious disease, and cancer, have only recently been identified. While short term use of chloroquine or hydroxychloroquine is safe at traditional therapeutic doses in patients without predisposing conditions, administration of higher doses and for longer durations are associated with toxicity, including retinotoxicity. Additional liabilities of these medications include pharmacokinetic profiles that require extended dosing to achieve therapeutic tissue concentrations. To improve chloroquine therapy, researchers have turned toward nanomedicine reformulation of chloroquine and hydroxychloroquine to increase exposure of target tissues relative to off-target tissues, thereby improving the therapeutic index. This review highlights these reformulation efforts to date, identifying issues in experimental designs leading to ambiguity regarding the nanoformulation improvements and lack of thorough pharmacokinetics and safety evaluation. Gaps in our current understanding of these formulations, as well as recommendations for future formulation efforts, are presented.     

Investigating interactions between chloroquine/hydroxychloroquine and their single enantiomers and angiotensin-converting enzyme 2 by a cell membrane chromatography method

Chloroquine and hydroxychloroquine have been studied since the early clinical treatment of SARS-CoV-2 outbreak. Considering these two chiral drugs are currently in use as the racemate, high-expression angiotensin-converting enzyme 2 cell membrane chromatography was established for investigating the differences of two paired enantiomers binding to angiotensin-converting enzyme 2 receptor. Molecular docking assay and detection of SARS-CoV-2 spike pseudotyped virus entry into angiotensin-converting enzyme 2-HEK293T cells were also conducted for further investigation. Results showed that each single enantiomer could bind well to angiotensin-converting enzyme 2, but there were differences between the paired enantiomers and corresponding racemate in frontal analysis. R-Chloroquine showed better angiotensin-converting enzyme 2 receptor binding ability compared to S-chloroquine/chloroquine (racemate). S-Hydroxychloroquine showed better angiotensin-converting enzyme 2 receptor binding ability than R-hydroxychloroquine/hydroxychloroquine. Moreover, each single enantiomer was proved effective compared with the control group; compared with S-chloroquine or the racemate, R-chloroquine showed better inhibitory effects at the same concentration. As for hydroxychloroquine, R-hydroxychloroquine showed better inhibitory effects than S-hydroxychloroquine, but it slightly worse than the racemate. In conclusion, R-chloroquine showed better angiotensin-converting enzyme 2 receptor binding ability and inhibitory effects compared to S-chloroquine/chloroquine (racemate). S-Hydroxychloroquine showed better angiotensin-converting enzyme 2 receptor binding ability than R-hydroxychloroquine/hydroxychloroquine (racemate), while the effect of preventing SARS-CoV-2 pseudovirus from entering cells was weaker than R-hydroxychloroquine/hydroxychloroquine (racemate).     

A Capillary Electrophoresis-Based Method for the Measurement of Hydroxychloroquine and Its Active Metabolite Desethyl Hydroxychloroquine in Whole Blood in Patients with Rheumatoid Arthritis

A capillary electrophoresis method was developed to detect and measure hydroxychloroquine (HCQ) and its active metabolite desethyl hydroxychloroquine (DHCQ) in whole blood in patients with rheumatoid arthritis. The best separation in terms of peak area reproducibility, migration time, peak shape, and resolution of adjacent peaks was obtained in a 60 cm, 75 µm i.d. uncoated fused-silica capillary using a background electrolyte mixture of an aqueous 55 mmol/L TRIS solution brought to pH 2.6 with phosphoric acid and methanol (85:15) and a voltage and a temperature of separation of 20 kV and 30 °C, respectively. Analytes were separated in less than 12 min, with excellent linearity (R² ≥ 0.999) in the concentration range of 0.5–8 µmol/L. The recovery of analytes spiked in whole blood was 99–101% for HCQ and 98–99% for DHCQ. Analysis of five samples from patients with rheumatoid arthritis receiving HCQ 400 mg daily yielded mean steady-state concentrations of 2.27 ± 1.61 and 1.54 ± 0.55 μmol/L for HCQ and DHCQ, respectively, with a HCQ to DHCQ ratio of 1.40 ± 0.77.     

Development of a novel ion‐pairing HPLC‐FL method for the separation and quantification of hydroxychloroquine and its metabolites in whole blood

Hydroxychloroquine (HCQ) is an old antimalarial drug that has proven to be a safe and effective treatment for systemic lupus erythematosus (SLE) and other autoimmune diseases. Since hematic concentration of HCQ is closely related to the therapeutic response, monitoring the levels of the drug and its metabolites in the blood of HCQ‐treated patients helps the clinician in the evaluation of partial or complete unresponsiveness to treatment. We developed and validated a novel ion‐pairing HPLC‐FL method for the simultaneous dosage of HCQ, and its major metabolites desethylhydroxychloroquine, desethylchloroquine and bisdesethylchloroquine, after extraction from whole blood. This methodological approach was used for the analysis of real samples obtained from patients affected by SLE and undergoing HCQ treatment. The same samples were also analyzed using a previously validated LC/MS/MS method and data obtained with the two approaches were in substantial agreement with each other. Results presented in this work indicate that this approach can be successfully used to monitor the level of HCQ and its metabolites in the blood of various categories of patients (i.e. low and high responders, or those not adhering to the therapy). Comparison of HPLC‐FL and LC/MS/MS data confirmed the efficacy of the proposed method for routine clinical analyses.     

A Review of Modifications of Quinoline Antimalarials: Mefloquine and (hydroxy)Chloroquine

Late-stage modification of drug molecules is a fast method to introduce diversity into the already biologically active scaffold. A notable number of analogs of mefloquine, chloroquine, and hydroxychloroquine have been synthesized, starting from the readily available active pharmaceutical ingredient (API). In the current review, all the modifications sites and reactivity types are summarized and provide insight into the chemistry of these molecules. The approaches include the introduction of simple groups and functionalities. Coupling to other drugs, polymers, or carriers afforded hybrid compounds or conjugates with either easily hydrolyzable or more chemically inert bonds. The utility of some of the compounds was tested in antiprotozoal, antibacterial, and antiproliferative assays, as well as in enantiodifferentiation experiments.