LC-MS/MS Method Development and Validation for Determination of Favipiravir Pure and Tablet Dosage Forms.

Objectives: Analytical method development and validation for determination of favipiravir (FVPR) in pure and tablet dosage forms by liquid chromatography with tandem mass spectrometry/mass spectrometry (LC-MS/MS) technique. Materials and Methods: A simple LC-MS/MS method was developed for determination of a new antiviral drug, FVPR in pharmaceutical formulations. The stationary phase employed was a Shim pack GISS, C18 (100 mm × 2.1 mm, 1.9 µm) column and mobile phase used in pump A was 10.0 mM ammonium acetate and in pump B methanol was used. The gradient program was used with fixed mobile phase flow rate at 0.4 mL min-1. Total run time was 5.0 min. The proposed method was validated according to International Conference on Harmonization (ICH) guidelines. The established method found better outcomes. Results: The linearity graph was found in the range of 50-200 µg/mL and the correlation coefficient value (R2) obtained was found to be 1.0. The limit of detection (LOD) and limit of quantification (LOQ) were 4.044 µg/mL and 12.253 µg/mL, respectively. Tremendous recovery outcomes were observed and found to be 101%, 99.0%, and 99.5% for FVPR at 150% upper, 100% middle, and 50% lower concentrations, respectively. Conclusion: All outcomes obtained comply with ICH guidelines. The developed method was simple, unique, accurate, robust, precise, and reproducible for determination of FVPR in tablet formulation. The method is novel and could be adopted in formulation industry.

Molecular spectroscopic and docking analysis of the interaction of fluorescent thiadicarbocyanine dye with biomolecule bovine serum albumin.

Binding studies of the water-soluble thiadicarbocyanine dye 3,3'-diethylthiadicarbocyanine acetate (DTC) with bovine serum albumin (BSA) were examined under physiological conditions using spectroscopic techniques like fluorescence, UV-Visible, circular dichroism (CD), FT-IR and molecular docking methods. Compiled experimental results envisage that DTC quench the fluorescence intensity of BSA. The increasing binding constants (K) were found to be in the order of 103 Mol-1 as a function of temperature, as calculated from the fluorescence quenching data. The quenching mechanism, thermodynamic parameters (ΔH0, ΔS0 and ΔG0) and the number of binding sites have been explored. CD values showed that the secondary structure of the BSA has been altered upon binding to DTC. Displacement experiments were carried out with different site probes to find out the binding site of DTC on BSA and it was found that binding interaction at site II of sub-domain IIIA. The interference of common metal ions on the interaction of DTC with BSA has also been studied. The experimental data exhibit that DTC interacts with BSA by hydrophobic forces. The experimental findings from BSA binding studies were validated by using in silico molecular docking technique. The results of the investigations were accurately supported by studies on molecular docking. The optimal shape of the molecular probe demonstrated the affinity as a free binding energy release of -7.37 Kcal/mol. The present research report endeavors to the approachable nature of water-soluble DTC dye and paves way for targeted biological interactions.Communicated by Ramaswamy H. Sarma.

BSA binding and antibacterial studies of newly synthesized 5,6-Dihydroimidazo[2,1-b]thiazole-2-carbaldehyde.

A new heterocyclic compound, 5,6-Dihydroimidazo[2,1-b]thiazole-2-carbaldehyde (ITC) was synthesized and its antibacterial activity and also its interaction with bovine serum albumin (BSA) were studied. The structure of the synthesized compound was confirmed by 1H NMR, 13C NMR and IR spectroscopic techniques. The antibacterial activity was carried out by minimum inhibitory concentration (MIC) method. The compound showed a good antibacterial activity. The mechanism of interaction between the BSA and ITC under physiological conditions was investigated by various molecular spectroscopic techniques like, fluorescence, circular dichroism (CD), UV absorption and FT-IR. The interaction between ITC and BSA was followed by studying the quenching of intrinsic fluorescence of BSA upon the addition of ITC at three different temperatures. The binding constant (K), Stern-Volmer quenching constant (Ksv) and number of binding sites were determined. The separation distance between BSA and ITC was evaluated based on the fluorescence resonance energy transfer theory. The conformational changes in BSA upon binding of ITC were also confirmed. The interference of some metal ions on interaction was studies. The displacement studies with site specific markers confirm that the site III was the binding site for ITC on BSA.