Quality-by-design ecofriendly potentiometric sensor for rapid monitoring of hydroxychloroquine purity in the presence of toxic impurities

Hydroxychloroquine (HCQ) is prescribed to treat malaria and certain autoimmune diseases. Recent studies questioned its efficiency in relieving COVID-19 symptoms and improving clinical outcomes. This work presents a quality-by-design approach to develop, optimize, and validate a potentiometric sensor for the selective analysis of HCQ in the presence of its toxic impurities (key starting materials), namely 4,7-Dichloroquinoline (DCQ) and hydroxynovaldiamine (HND). The study employed a custom experimental design of 16 sensors with different ion exchangers, plasticizers, and ionophores. We observed the Nernstian slopes, correlation coefficients, quantification limit, response time, and selectivity coefficient for DCQ and HND. The computer software constructed a prediction model for each response. The predicted responses strongly correlate to the experimental ones, indicating model fitness. The optimized sensor achieved 93.8% desirability. It proved a slope of 30.57 mV/decade, a correlation coefficient of 0.9931, a quantification limit of 1.07 × 10-6 M, a detection limit of 2.18 × 10-7 M, and a fast response of 6.5 s within the pH range of 2.5-8.5. The sensor was successfully used to determine HCQ purity in its raw material. The sensor represents a potential tool for rapid, sensitive, and selective monitoring of HCQ purity during industrial production from its starting materials.

A Box-Behnken design-based chemometric approach to optimize the sono-photodegradation of hydroxychloroquine in water media using the Fe(0)/S2O82-/UV system

The huge utilization of hydroxychloroquine in autoimmune infections led to an abnormal increment in its concentration in wastewater, which can pose a real risk to the environment, necessitating the development of a pretreatment technique. To do this, we are interested in researching how hydroxychloroquine degrades in contaminated water. The main goal of this investigation is to optimize the operating conditions for the sono-photodegradation of hydroxychloroquine in water using an ultrasound-assisted Fe(0)/S 2 O 8 2 - /UV system. To get adequate removal of HCQ, a chemometric method based on the Box-Behnken design was applied to optimize the influence of the empirical parameters selected, including Fe(0) dose,S 2 O 8 2 - concentration, pH, and initial HCQ concentration. The quadratic regression model representing the HCQ removal rate (η(%)) was evolved and validated by ANOVA. The optimal conditions as a result of the above-mentioned trade-off between the four input variables, with η(%) as the dependent output variable, were captured using RSM methodology and the composite desirability function approach. For HCQ full decomposition, the optimal values of the operating factors are as follows:S 2 O 8 2 - dose, 194.309 mg/L; Fe(0) quantity, 198.83 mg/L; pH = 2.017, and HCQ initial dose of 296.406 mg/L. Under these conditions, the HCQ removal rate, achieved after 60 min of reaction, attained 98.95%.

Liquid Chromatographic Methods for COVID-19 Drugs, Hydroxychloroquine and Chloroquine

COVID-19 has been a threat throughout the world since December 2019. In attempts to discover an urgent treatment regime for COVID-19, hydroxychloroquine (HCQ) and chloroquine (CQ) have been on solidarity clinical trial. However, many countries have pulled HCQ and CQ from their COVID-19 treatment regimens recently, some countries still continue using them for patients who have previously started HCQ and CQ and they may complete their course under the supervision of a doctor. HCQ and CQ are 4-aminoquinoline drugs and it is safe to use them for autoimmune diseases, rheumatoid arthritis, systemic lupus erythematosus and malaria as well. Determination of CQ, HCQ and their metabolites in biologic fluids and in pharmaceuticals has great importance, especially for pharmacokinetics, pharmacodynamics and epidemiological studies. In this review, liquid chromatographic methods developed in the last 10 years were summarized focusing on sample preparation and detection methods for HCQ and CQ determination in biological fluids and pharmaceutical preparations. It is hoped that this article could be helpful to facilitate the use of these drugs in clinical trials or drug research studies as it provides comprehensive information on the reported analytical methods.

The role of photodegradation in the environmental fate of hydroxychloroquine

For many organic pollutants present in surface waters, photolysis is considered as a major abiotic degradation process. The present study aimed to explore the role of photolysis in the environmental fate of hydroxychloroquine (HCQ) for the first time. The photolytic degradation of HCQ was investigated under simulated solar radiation (300-800 nm) in ultrapure, spring, river, and sea water. The effect of pH on the photodegradation rate was substantial and it was observed that degradation was faster at higher pH-values. Obtained half-lives ranged from 5.5 min at pH 9 to 23.1 h at pH 4. Humic acids, nitrate and iron(III) enhanced photodegradation of HCQ due to formation of hydroxyl radicals and its attack on HCQ molecule. In contrast, chloride, sulfate and bromide inhibited photodegradation. Additionally, the humic acids exhibited a dual role, photosensitization and inner filter effect. The study of the reaction kinetics was performed with HPLC-PDA, while the identification of degradation products formed during photolytic degradation was carried out using HPLC-MS/MS and NMR spectroscopy. The hydroxylation was recognized as the dominant path of photoproducts formation. The results of this research reveal the importance of photolytic degradation in environmental fate of HCQ and enable a better understanding of its behavior in the environment. Moreover, the results showing the significant effect of pH on the photodegradation of HCQ can be very useful in water treatment processes.

Enantioselective analysis of the metabolites of hydroxychloroquine and application to an in vitro metabolic study

A one-step chiral method for the quantification of the enantiomers of two hydroxychloroquine (HCQ) metabolites, desethylchloroquine (DCQ) and desethylhydroxychloroquine (DHCQ) by HPLC is described, in addition to its application to the in vitro study of HCQ metabolism in rat liver microsomes. Liquid-liquid extraction was used to extract the enantiomers from microsome samples and the separation was performed on a Chiralpak AD-RH column protected with an RP-8 guard column using hexane:isopropanol (92:8, v/v) plus 0.1% diethylamine as the mobile phase, at a flow rate of 1.0 mL min(-1). The detection was carried out at 343 nm. The method proved to be linear in the range of 50-5000 ng mL(-1) for DCQ enantiomers and 125-2500ngmL(-1) for DHCQ enantiomers, with a quantification limit of 50 and 125 ng mL(-1), respectively. Precision and accuracy, demonstrated by within-day and between-day assays, were lower than 15%. The metabolic study demonstrated that metabolism is stereoselective for HCQ. The major metabolites formed in the incubation of racemic HCQ were (-)-(R)-DCQ and (-)-(R)-DHCQ with R/S ratios of 2.2 and 3.3, respectively.

Electrochemical study of hydroxychloroquine and its determination in plaquenil by differential pulse voltammetry

Hydroxychloroquine (HCQ) is a halogenated aminoquinoline that presents wide biological activity, often being used as an antimalarial drug. The electrochemical reduction of HCQ was investigated by cyclic voltammetry and chronoamperometry using glassy carbon electrodes. By cyclic voltammetry, in acid medium, only the cathodic peak was observed. The electrochemical behavior of this peak is dependent on pH and the electrodic process occurs through an E(r)C(i) mechanism. The electron number (1e) consumed in the reduction of HCQ was obtained by chronoamperometry. A method for the electrochemical determination of HCQ in pharmaceutical tablets was developed using differential pulse voltammetry. The detection limit reached was 11.2 microg ml(-1) of HCQ with a relative standard deviation of 0.46%. A spectrophotometric study of HCQ has been also carried out utilizing a band at 343 nm. The obtained detection limit and the relative standard deviation were 0.1 microg ml(-1) and 0.36%, respectively. The electrochemical methods are sufficiently accurate and precise to be applied for HCQ determination, in laboratorial routine, which can be used to determine the drug at low level.