Chromatographic determination of itopride hydrochloride in the presence of its degradation products

Two sensitive and reproducible methods are described for the quantitative determination of itopride hydrochloride (IH) in the presence of its degradation products. The first method is based on HPLC separation on a reversed phase Kromasil column [C18 (5-microm, 25 cm x 4.6 mm, ID)] at ambient temperature using a mobile phase consisting of methanol and water (70:30, v/v) adjusted to pH 4.0 with orthophosphoric acid with UV detection at 258 nm. The flow rate was 1.0 mL per min with an average operating pressure of 180 kg/cm2. The second method is based on HPTLC separation on silica gel 60 F254 using toluene:methanol:chloroform:10% ammonia (5.0:3.0:6.0:0.1, v/v/v/v) as mobile phase at 270 nm. The analysis of variance (ANOVA) and Student's t-test were applied to correlate the results of IH determination in dosage form by means of HPLC and HPTLC methods. The drug was subjected to acid and alkali hydrolysis, oxidation, dry heat, wet heat treatment, UV, and photodegradation. The proposed HPLC method was utilized to investigate the kinetics of the acidic, alkaline, and oxidative degradation processes at different temperatures and the apparent pseudo-first-order rate constant, half-life, and activation energy were calculated. In addition the pH-rate profile of degradation of IH in constant ionic strength buffer solutions in the pH range 2-11 was studied.     

A facile and rapid access towards the synthesis of 2,3-dihydroquinazolin-4(1H)-ones

An efficient synthetic route for 2,3-dihydroquinazolin-4(1H)-ones using 2-morpholinoethanesulfonic acid as a potential and new organocatalyst is described. The developed synthetic protocol represents a novel and very simple route for the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives. In addition, microwave irradiation technique is successfully implemented for carrying out the reactions in shorter reaction times.     

Green multicomponent reaction for synthesis of trisubstituted pyrroles in ionic liquid [bmim]BF<Subscript>4</Subscript>

2,4,5-Trisubstituted pyrrole derivatives were efficiently synthesized by one-pot condensation of 1,3-diones, α-bromoacetophenones, and ammonium acetate in ionic liquid [bmim]BF₄. The new synthetic method offers multisubstituted pyrroles with the advantages of mild reaction conditions, operational simplicity, higher yield, and environmental friendliness.     

Adsorption of Metformin on Graphene Nanoribbons and Application in Treatment of Oral Cancer Using Photothermal Energy

Graphene nanoribbons are thin sheets of graphene showing exclusive characteristics such as better drug-loading capacity, adsorption on mammalian cells, greater surface area, and light-absorbing ability. The current research work is to develop metformin-adsorbed carboxyl-functionalized oxidized graphene nanoribbons and utilize drug repurposing for the treatment of oral cancer by activating photo-thermal radiation therapy. The nanoribbons are formulated by Hummer's method and evaluated for several characterization parameters like ATR- Fourier Transform Infrared (FTIR), Differential scanning calorimetry (DSC), topology, in vitro efficacy, ex vivo and in vitro cell line studies. The ATR-FTIR spectrum of formulated nanoribbons shows distinctive peak at 3370 cm⁻¹ ( N H group) of metformin. The DSC specifies the incidence of steep endothermic crests at 235 °C ( C NH₃). The in vitro and ex vivo drug release studies show enhanced drug release in acidic pH (6.4) than physiological pH (7.4) with photothermal radiation. The in vitro cell line studies are processed via two-way ANOVA that exhibits 67.74 ± 0.03% of % inhibition in presence of photothermal radiation. The study demonstrates higher inhibition of cancerous cells at lower concentration of drug and photothermal therapy in comparison to plain drug. The characteristic feature of graphene is used to develop targeted drug delivery system against the oral cancerous cells.     

Hydrothermal Assisted Synthesis of Micro-Bricks Shaped WO3 for Electrochemical Oxidation of Paracetamol: A Microstructured Paracetamol Sensor

Russian Journal of Electrochemistry - A micro-bricks shaped tungsten oxide (WO3) was prepared by hydrothermal method. The prepared material was characterized by field emission scanning electron...     

2-Nitrobenzaldehyde Thiocarbohydrazone Assisted Precise Extraction Spectrophotometric Method for the Determination of Ruthenium(III) in Alloy and Catalysts

A simple, rapid, selective, sensitive and reliable extractive spectrophotometric method was developed for the determination of ruthenium(III) using 2-nitrobenzaldehyde thiocarbohydrazone (2-NBATCH) as a chromogenic chelating ligand. The ruthenium(III)?2-NBATCH complex is formed in aqueous acetic acid media (0.7 M) containing an organic solvent after 5 min heating on a water bath. The red colored complex is extracted into 1,2-dichloroethane and absorbance is measured at 445 nm against reagent blank. The Beer’s law is obeyed within 1?6 g/mL of ruthenium(III), the optimum concentration range was 2?5 g/mL of ruthenium(III) evaluated by Ringbom’s plot. Molar absorptivity and Sandell’s sensitivity of complex were 1.41 × 10⁴ L/mol/cm and 0.0075 μg/cm², respectively. The stoichiometry of complex was 1: 3 established from Job’s method of continuous variation, molar ratio method and logarithmic slope method. The proposed method was applied for determination of ruthenium(III) in binary and ternary, synthetic mixtures corresponding to fission product elements alloy and ruthenium(III) catalysts.     

Uridate/pyridyl Pd(II) complexes: Phosphine-free high turnover catalysts for the Heck reaction of deactivated aryl bromides

The synthesis and structure of palladium(II) complexes bearing uridato/pyridyl ligands as an anionic N-donor coordination sites are reported. The complexes have been shown to be highly active catalysts for the Heck reaction of aryl bromides (TON 4.0×10⁴-9.1×10⁴) and moderate activity for the activation of aryl chlorides under phosphine-free conditions.     

Experimental investigation and simulation of hollow fiber membrane process for SF6 recovery from GIS

In this present study, polyethersulfone hollow fiber membrane was used to recover sulfur hexafluoride (SF₆) from gas‐insulated switchgear (GIS). SF₆, N₂ pure gas and mixed gas (12.5 vol.% of SF₆) experiment was initiated to observe permeation behavior according to temperature and pressure difference and retentate flow rate. Scanning electron microscopy was used to investigate the morphological characteristics and the structure of asymmetric hollow fibers. The permeation rates of SF₆ and N₂ were measured by the variable pressure method. As a result, permeance of N₂ was 9.5–16.3 GPU, and selectivity of N₂/SF₆ was 10.5–13.3. Moreover, the concentration of SF₆ in the retentate stream reached to 99.2% by the control of the operating condition. Based on the experimental results, tree‐stage membrane process was designed using simulation program. As a result, demanded membrane area reduced about 74% according to operating condition difference. Copyright © 2013 John Wiley & Sons, Ltd.     

Solution-phase synthesis of a tricyclic pyrrole-2-carboxamide discovery library applying a stetter-Paal-Knorr reaction sequence

The solution-phase synthesis of a discovery library of 178 tricyclic pyrrole-2-carboxamides was accomplished in nine steps and seven purifications starting with three benzoyl-protected amino acid methyl esters. Further diversity was introduced by two glyoxaldehydes and 41 primary amines. The combination of Pauson-Khand, Stetter, and microwave-assisted Paal-Knorr reactions was applied as a key sequence. The discovery library was designed with the help of QikProp 2.1, and physicochemical data are presented for all pyrroles. Library members were synthesized and purified in parallel and analyzed by LC/MS. Selected compounds were fully characterized.