Fluorimetric Determination of Antiviral (COVID-19) Drug Favipiravir in Bulk and Pharmaceutical Dosage Forms

Favipiravir is a synthetic prodrug, which was first discovered while assessing the antiviral activity of chemical agents active against the influenza virus in the chemical library of Toyoma chemicals. It works by inhibiting RNA dependant RNA polymerase (RdRP), an enzyme required for RNA viral replication inside human cells. A simple, rapid, and economic method was developed for the quantitative determination of Favipiravirusing spectrofluorometer. The Favipiravir standard drug solution and sample tablet solution was prepared using double distilled water as a diluent. The different concentrations ofpure drugin the range 2-10 μg/ml and one sample solution were measured for the intensity at 432nm in the spectrofluorometer. The calibration curve was plotted and the sample’s unknown concentration was calculated from the plot. The calibration curve was found to be linear with r2 value obtained as 0.99.There are various other methods available for the quantification of Favipiravir which include RP-HPLC, UV-spectroscopic methods, FTIR, LC-MS with different extraction methods spiked in human plasma but not by using spectrofluorometer. Favipiravir shows fluorescence when dissolved in appropriate solvent hencethis method was developed to quantify Favipiravir which is a simple and efficient method. This method developed is easy and can be used for routine quality control test for Favipiravir pharmaceutical formulations. Keywords: Favipiravir, spectrofluorometer, Calibration curve

A simple process for the preparation of pralidoxime chloride

431-435Pralidoxime chloride (2-PAM chloride) is an important drug included in National List of Essential Medicines-2003 for treating pesticide poisoning. However, the current methods for its preparation use hazardous methyl halides such as methyl chloride or methyl iodide. In the present work, reaction of pyridine-2-aldoxime with methyl methanesulfonate in acetonitrile gave 2-PAM mesylate in high yields (90%). Use of methyl tosylate in toluene resulted in 2-PAM tosylate (90% yield). Both 2-PAM mesylate and 2-PAM tosylate on treatment with dry hydrogen chloride in isopropanol, resulted in 2-PAM chloride in high yields (90%) and purity (>99%)

DEVELOPMENT AND VALIDATION OF UV SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS ESTIMATION OF SITAGLIPTIN AND METFORMIN IN BULK AND COMBINED PHARMACEUTICAL FORMULATION

Objective: To develop simple, accurate, precise UV Spectrophotometric method for the simultaneous estimation of Sitagliptin and Metformin in tablet dosage form. Methodols: The method is based on the determination of Sitagliptin and Metformin in tablet using simultaneous equation method. Sitagliptin exhibits maximum absorbance at 267 and Metformin exhibits maximum absorbance at 237 nm using distilled water as diluents. Results: The calibration curve was linear in the range of 10-300 µg/ml for Sitagliptin and 4-14µg/ml for Metformin. The %RSD were within the limit i.e., less than 2%. The % recovery of the proposed method was found to be 97.12-99.46% for Sitagliptin and 98.15-99.85% for Metformin. The LOD of the proposed method was 0.397μg/ml for Sitagliptin and 0.8952µg/ml for Metformin. The LOQ was 1.2951μg/ml for Sitagliptin and 2.7159μg/ml for Metformin. Conclusion: A simple, accurate, precise UV Spectrophotometric method for the simultaneous estimation of Sitagliptin and Metformin in tablet dosage form

Virtual screening of cathepsin K inhibitors using docking and pharmacophore models

Cathepsin K is a lysosomal cysteine protease that is highly and selectively expressed in osteoclasts, the cells which degrade bone during the continuous cycle of bone degradation and formation. Inhibition of cathepsin K represents a potential therapeutic approach for diseases characterized by excessive bone resorption such as osteoporosis. In order to elucidate the essential structural features for cathepsin K, a three-dimensional pharmacophore hypotheses were built on the basis of a set of known cathepsin K inhibitors selected from the literature using catalyst program. Several methods are used in validation of pharmacophore hypothesis were presented, and the fourth hypothesis (Hypo4) was considered to be the best pharmacophore hypothesis which has a correlation coefficient of 0.944 with training set and has high prediction of activity for a set of 30 test molecules with correlation of 0.909. The model (Hypo4) was then employed as 3D search query to screen the Maybridge database containing 59 000 compounds, to discover novel and highly potent ligands. For analyzing intermolecular interactions between protein and ligand, all the molecules were docked using Glide software. The result showed that the type and spatial location of chemical features encoded in the pharmacophore are in full agreement with the enzyme inhibitor interaction pattern identified from molecular docking