Due to the unavailability specific drugs or vaccines (FDA approved) that can cure COVID-19, the development of potent antiviral drug candidates/therapeutic molecules against COVID-19 is urgently required. This study was aimed at in silico screening and study of polyphenolic phytochemical compounds in a rational way by virtual screening, molecular docking and molecular dynamics studies against SARS-CoV-2 main protease (Mpro) and papain-like protease (PLpro) enzymes. The objective of the study was to identify plant-derived polyphenolic compounds and/or flavonoid molecules as possible antiviral agents with protease inhibitory potential against SARS-CoV-2. In this study, we report plant-derived polyphenolic compounds (including flavonoids) as novel protease inhibitors against SARS-CoV-2. From virtual docking and molecular docking study, 31 polyphenolic compounds were identified as active antiviral molecules possessing well-defined binding affinity with acceptable ADMET, toxicity and lead-like or drug-like properties. Six polyphenolic compounds, namely, enterodiol, taxifolin, eriodictyol, leucopelargonidin, morin and myricetin were found to exhibit remarkable binding affinities against the proteases with taxifolin and morin exhibiting the highest binding affinity toward Mpro and PLpro respectively. Molecular dynamics simulation studies of these compounds in complex with the proteases showed that the binding of the compounds is characterized by structural perturbations of the proteases suggesting their antiviral activities. These compounds can therefore be investigated further by in vivo and in vitro techniques to assess their potential efficacy against SARS-CoV-2 and thus serve as the starting point for the development of potent antiviral agents against the deadly COVID-19. Communicated by Ramaswamy H. Sarma

Three crucial anticancer scaffolds, namely indolin-2-one, 1,3,4-thiadiazole, and aziridine, are explored to synthesize virtually screened target molecules based on the c-KIT kinase protein. The stem cell factor receptor c-KIT was selected as target because most U.S. FDA-approved receptor tyrosine kinase inhibitors bearing the indolin-2-one scaffold profoundly inhibit c-KIT. Molecular hybrids of indolin-2-one with 1,3,4-thiadiazole (IIIa-m) and aziridine (VIa and VIc) were afforded through a modified Schiff base green synthesis using β-cyclodextrin-SO₃H in water as a recyclable proton-donor catalyst. A computational study found that indolin-2,3-dione forms a supramolecular inclusion complex with β-cyclodextrin-SO₃H through noncovalent interactions. A molecular docking study of all the synthesized compounds was executed on the c-KIT kinase domain, and most compounds displayed binding affinities similar to that of Sunitinib. On the basis of the pharmacokinetic significance of the aryl thioether linkage in small molecules, 1,3,4-thiadiazole hybrids (IIIa-m) were extended to a new series of 3-((5-(phenylthio)-1,3,4-thiadiazol-2-yl)imino)indolin-2-ones (IVa-m) via thioetherification using bis(triphenylphosphine)palladium(II)dichloride as the catalyst for C-S bond formation. Target compounds were tested against NCI-60 human cancer cell lines for a single-dose concentration. Among all three series of indolin-2-ones, the majority of compounds demonstrated broad-spectrum activity toward various cancer cell lines. Compounds IVc and VIc were further evaluated for a five-dose anticancer study. Compound IVc showed a potent activity of IC₅₀ = 1.47 μM against a panel of breast cancer cell lines, whereas compound VIc exhibited the highest inhibition for a panel of colon cancer cell lines at IC₅₀ = 1.40 μM. In silico ADME property descriptors of all the target molecules are in an acceptable range. Machine learning algorithms were used to examine the metabolites and phase I and II regioselectivities of compounds IVc and VIc, and the results suggested that these two compounds could be potential leads for the treatment of cancer.

Background: In the current study, a simple, improved, precise, rapid, and accurate reverse phase liquid chromatographic method was produced for the estimation of dalfampridine in bulk and tablet dosage form which is a potassium channel blocker used for the treatment of multiple sclerosis (MS). The separation of dalfampridine was achieved isocratically on a C₁₈ column (250 × 4.6 mm, 5 μm) using (0.1% v/v) buffer pH 3.0 ± 0.05 adjusted with diluted orthophosphoric acid (OPA) and acetonitrile (ACN) in the ratio of 60:40% (v/v) as a mobile phase, at a flow rate of 0.5 mL/min, and column temperature of 40 °C. HPLC grade methanol as diluents was used. Five microliters of the standard solution of the drug was injected, and the eluted analytes were detected at 262 nm. Results: Dalfampridine was eluted at 4.5 min with a run time of 10 min. Linearity in the method was measured in the concentration range of 25–75 ppm with a correlation coefficient of 0.999. Limit of detection and limit of quantitation were found to be 0.711 μg/mL and 2.154 μg/mL, respectively. Dalfampridine was subjected for forced degradation stability study in conditions of thermal, acid, alkali, and oxidation and photo-degradation condition. The degradants were well resolved from the dalfampridine main peak. Validation of the developed method is carried as per USFDA and ICH guidelines. Conclusion: The results of the analysis prove that the method is simple, improved, precise, accurate, and rapid for estimating the content of dalfampridine in bulk drug and tablet dosage form and can be applied for routine analysis.

Forced degradation studies in tablet and bulk formulations of remogliflozin etabonate have been developed using a precise and sensitive high performance thin layer chromatographic method. The silica gel RP-18 F254S plates were used as the stationary phase and ACN: water: ammonia solution (8:2:0.5 V/V/V) was used as the mobile phase for estimation. The proposed method was successfully validated, showing the Rf of the drug as 0.72 at 229 nm. The method was observed to be linear in the range of 500-3000 ng band-1 and then degradation was estimated by forced degradation pathway. In the forced degradation studies, the drug was found to be highly susceptible to both acid and base, including oxidative conditions, providing an active metabolite when remaining in contact in stressed conditions for a short time (30 min), while in longer duration (36 h), the drug provided another metabolite which on characterization was found to be inactive and predicted to be reported in the metabolic pathway

Background: A precise, accurate, economical and reproducible UV, RP-HPLC and UPLC method has been developed for the estimation of Prenoxdiazine hydrochloride in pharmaceutical and bulk dosage form. Each of the developed method has been validated for the analysis of Prenoxdiazine hydrochloride. Result: The validation of the analytical methods was carried out based on various parameters like precision, linearity, accuracy, specificity, LOD, and LOQ for all the three methods. The parameters were found statistically significant for the analysis of Prenoxdiazine hydrochloride. The method was found sensitive in the presence of analytical impurities. The retention time of the Prenoxdiazine HCl was found to be 2.5 and 2.9 min, using common solvents acetonitrile and methanol, in UPLC and HPLC, respectively. Conclusion: The method may be useful in the wide range of analysis for the estimation of Prenoxdiazine hydrochloride. It is found to be robust upon the change in solvent flow rate, column temperatures. Further, the study has investigated the stability of the sample under stressed condition like thermal, oxidative, and photolytic. Here, we tried to develop and compare cost-effective methods for Prenoxdiazine HCl using most common industrial methods which are never studied.