Novel high throughput green UPLC-MS/MS methods for determination of desmopressin with special sample handling

Objectives of present investigation were to develop novel high throughput green UPLC-MS/MS methods for quality control of desmopressin formulations. Two liquid chromatographic methods: Method-I based on isocratic elution and method-II based on gradient elution were developed and validated. Methods were green, since less amount of organic solvent (≤75 ​μL, per sample run time) was utilized in mobile phase. Mobile phase (0.1% formic acid in ACN, and in water), flow rate was 300 ​μL/min. Desmopressin retention time and sample run time for Method-I were 0.59 and 1.0 ​min, respectively. Retention time and sample run time for method-II were 2.03 and 2.5 ​min, respectively. Double charged ions [M ​+ ​2H]²⁺ of desmopressin (m/z 535.33 ​> ​120) were monitored in multi-reaction monitoring mode. Desmopressin was directly analyzed in water samples. Calibration curves were prepared between 50 and 600 ​ng/mL. The values of r² were 0.999. Assay and dissolution study of desmopressin formulation was successfully performed using these methods. Desmopressin was found to adsorb or react with different type of materials while handling. The specific filters (Chromafil® Xtra PTFE-45/25 0.45 ​μm, syringe filter) and tubes (glass tubes or Neutral graduated micro test tubes) were used for handling desmopressin samples.     

Development and validation of analytical method for estimation of bilastine in bulk and pharmaceutical (tablet) dosage form

BackgroundThe present work describe a simple, linear, precise, robust, accurate and selective HPLC method for estimation of Bilastine in bulk and tablet dosage form. Bilastine is a second generation antihistamine medication. Generally it is used for treatment of allergic rhinoconjunctivitis and urticaria (hives). Methanol: Acetonitrile: Phosphoric Acid Buffer pH 2.1 in proportion of (21:33:46) was used as mobile phase with flow rate 1.0 ​ml/min. The column used for the method development is 250 ​× ​4.6 mm ​× ​5 ​μm dimension.ResultIn the range of 5–25 ​μg/ml the linearity of Bilastine shows a correlation coefficient of 0.9981.ConclusionThe method was validated as per ICH guidelines for linearity, precision, accuracy, robustness.     

Nano engineered biodegradable capsules for the encapsulation and kinetic release studies of ciprofloxacin hydrochloride

Polyelectrolyte based nano and micro capsules have been extensively studied as promising drug carrier in recent years. Natural degradable capsules have received great deal of attention due to their fascinating structural and morphological characteristics, biocompatibility, sustained and targeted-release capabilities. In this work, chitosan - dextran sulphate nano capsules were prepared via Layer-by-Layer (L-b-L) technique using sacrificial template for drug delivery applications. The loading and in vitro release studies were performed using ciprofloxacin hydrochloride as a model drug. The release media used in the study are plain water and Phosphate Buffered Saline (PBS). The optimum drug load was 389 ​μg, at a loading pH of 2.1 and a temperature of 25 ​°C for 50 ​min encapsulation time. The drug loaded capsules exhibited a slow and sustained release up to 24 ​h and the maximum release rate was obtained at pH 1.2 in water and pH 7.4 in PBS. Least amount of drug release occurred at pH 5.0 in both the release media. The amounts of drug release in water at pH 1.2, pH 5.0 and pH 7.4 are 309 ​μg, 163 ​μg and 251 ​μg respectively where as the corresponding values in the case of PBS (at pH 1.2, pH 5.0 and pH 7.4) are 236 ​μg, 198 ​μg and 251 ​μg respectively. Two different models namely, Ritger - Peppas and Higuchi models were chosen to study the release kinetics behaviour of ciprofloxacin hydrochloride. The prepared bio-degradable capsules had potential as drug carrier for targeting antibacterial drugs with diverse functionality.     

Standardisation of cooking and conditioning methods for preparation of quick cooking germinated brown rice

Quick cooking germinated brown rice (QCGBR) is a novel convenient food product with valuable health benefits. Different cooking and conditioning methods were studied for standardisation of its preparation process. Freshly harvested paddy of Prativa variety was milled in rubber roll sheller to get brown rice which was soaked in demineralised water at 30 ​± ​2 ​°C for 12 ​h followed by 24 ​h of germination in an incubator maintained at 27 ​± ​1 ​°C temperature and 85–90% relative humidity to obtain germinated brown rice. The germinated brown rice was immediately cooked using three different cooking methods such as atmospheric cooking at normal ambient pressure, pressure cooking with water in a domestic pressure cooker at 1 ​bar gauge pressure and pressure steaming (without water) with steam at 1 ​bar gauge pressure to predetermined cooking time. The cooked samples after washing were then conditioned by keeping them at 4 ​°C for 24 ​h (refrigerated storage) or −10 ​°C for 24 ​h (frozen storage) in a house hold refrigerator. The stored samples were taken out after 24 ​h and tempered for 1 ​h followed by drying in a tray dryer at 90 ​°C to obtain the quick cooking germinated brown rice. The samples obtained from different cooking and conditioning methods were analysed for cooking quality, physico-chemical parameters, damaged grain percentage, GABA content and sensory attributes to standardise the cooking and conditioning methods. Cooking time, water uptake ratio, solid loss and volume expansion ratio of quick cooking germinated brown rice varied significantly with cooking and conditioning methods of its preparation (p ​< ​0.05). Though frozen conditioning resulted in lowest cooking time, it was not accepted by the sensory panel due to high damaged grain percentage, distorted shape and softness after cooking. The QCGBR obtained by pressure cooking method followed by refrigerated conditioning resulted in highest sensory score.     

Green synthesis and characterization of Fe doped ZnO nanoparticles and their interaction with bovine serum albumin

Herein we report an eco-friendly and cost efficient synthesis of Fe doped ZnO (TPFZO) nanoparticles using the extract of Thespesia polpulanea flowers as a stabilizing agent. The synthesized NPs have been characterized by XRD, FT-IR, UV-DRS, SEM, EDAX and TEM studies. The synthesized NPs were found to have the crystallite size in the range of 30–60 ​nm. The calculated band gap energies for ZO and TPFZO nanoparticles were 3.00 ​eV and 1.97 ​eV respectively. The size distribution of the ZO and TPFZO obtained from TEM were observed to be lying in the range 50–120 ​nm and 4–22 ​nm respectively. The interaction of TPFZO NPs with bovine serum albumin (BSA) has been studied using fluorescence and absorption titration methods. The results indicated that the nanoparticles quenched the BSA fluorescence at 340 ​nm via static quenching mode having a bimolecular quenching rate constant value of 6.21 ​× ​10¹³ Lmol⁻¹s⁻¹.     

Cytotoxicity of the gold complex based on mercaptotriazole – A comparison with the conventional cyanide electrolyte

The study presents the 3-(4,5-dımethylthıazol-2-yl)-2,5-dıphenyltetrazolıum bromıde (MTT) assay results on human erythroleukemia K562 ​cell line to compare the toxicity of electrolytes based on the mercaptotriazole gold complex (Au-MT) and gold potassium cyanide. Solutions immediately after mixing and after three months at different concentrations were compared, with a prolonged aging period, to a year, for the electrolytes at pH ​= ​9. Lower toxicity of new organic gold complex at pH ​= ​4, 7, and 12 than of alkaline cyanide electrolyte, but higher at pH ​= ​2, was determined. The solution of the Au-MT at pH ​= ​9 had comparable, but lower cell toxicity in the whole investigated period.     

MoS2 incorporated carbon allotropes (activated carbon,graphene, MWCNT) as electrodes in symmetric supercapacitors

Symmetric supercapacitor devices were fabricated from MoS₂ incorporated carbon allotropes such as activated carbon (AC)/MoS₂, graphene/MoS₂ and MWCNT/MoS₂. The device performance was evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The electrochemical properties of the devices fabricated from carbon allotropes (activated carbon, graphene, MWCNT) were remarkably enhanced to above 50% by the incorporation MoS₂ phases. Out of the three fabricated devices, electrochemical performance of AC/MoS₂ as found to be superior. The specific capacitance and energy density of this device is 216 ​F/g and 6.2 ​Wh/Kg respectively with excellent higher rate capability and longer cyclic durability. The devices fabricated from graphene/MoS₂ and MWCNT/MoS₂ has exhibited a specific capacitance value of 202 ​F/g and 161 ​F/g with an energy density value of 5.68 ​Wh/Kg and 3.95 ​Wh/Kg respectively.     

Effect on rheology and frying stability of edible oil before and after addition of fenugreek seeds

Rheological parameters of vegetable oils showed great changes during frying. The correlation between rheological behavior and viscosity measurements during frying can give a good overall estimate of frying oil quality. In the present study, rheological properties of rice bran oil (RBO) and soybean oil (SBO) during deep-frying of 13 ​min were investigated for consecutive 1st, 2nd, 3rd, and 4th frying at an interval of one week. To enhance the frying stability of RBO and SBO, fenugreek seeds (Trigonellafoenum graecum) was added during frying. The shear stress versus shear rate data was fitted to Newtonian and Herschel-Bulkley rheological models. The flow behavior of RBO and SBO with and without fenugreek seeds in before and after frying were measured at 30 ​± ​2 ​°C. The increase in viscosity, acid values and flow behavior index (n) with frying times for both RBO and SBO can be controlled with the addition of fenugreek seed up to 3rd frying with n ​< ​1 values, where without fenugreek seeds for RBO and SBO it showed a shear thickening properties (n ​> ​1) after 2nd and 3rd frying respectively.     

Optimization of solar photocatalytic biodegradability of seawater using statistical modelling

The performance of zinc oxide (ZnO) as a photocatalyst was evaluated for the treatment of pollutants present in seawater. Batch experimental studies were carried out by varying the dosage of photocatalyst (1–4 ​g/L). The effect of reaction time, pH and the dosage of photocatalyst was evaluated with the percentage removal efficiencies of chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC) and the biodegradability (BOD/COD) of the seawater. Response surface methodology-central composite design (RSM-CCD) and artificial neural network-Levenberg Marquardt (ANN-LM) statistical models were employed to optimize the photocatalytic biodegradability (BOD/COD). A quadratic polynomial statistical model was obtained to predict the percentage removal efficiencies of COD, TOC, BOD and biodegradability. For the experimental runs, the maximum percentage removal efficiencies for COD, TOC, BOD was found to be 62.3, 40.1, and 18.8%, respectively. Whereas, the maximum biodegradability was 0.036. As per RSM-CCD and ANN-LM statistical model method the maximum percentage removal efficiencies were found to be COD ​= ​58.14, 60.39%, TOC ​= ​33.74, 40.09%, BOD ​= ​18.47, 18.7% and Biodegradability ​= ​0.0315, 0.0360, respectively. The predicted values from statistical models were well correlated with experimental values. ANN modelling predicted better values for the responses with an average of R² ​= ​0.99697 than RSM modelling with average R² ​= ​0.8948.     

Impact of sulfuric acid pretreatment of durian peel on the production of fermentable sugar and ethanol

After harvesting season, large amounts of durian peels were produced and uselessly disposed of by combustion or landfilling leading to environmental pollution and human health hazards. Proper management of these wastes is necessary to reduce not only an environmental problem but also to create value-added products. Herein, we optimized sulfuric acid pretreatment to promote enzymatic saccharification of durian peels and convert fermentable sugars to bioethanol. Three pretreatment parameters were optimized based on Response Surface Methodology (RSM), including acid concentration (0.5%–3.5%), temperature (60–140 ​°C), and time (20–100 ​min). At optimal pretreatment condition using 2.75% H₂SO₄, at 127.14 ​°C for 74.13 ​min, 0.53 ​g/g-biomass of reducing sugars were produced, which is 1.88 folds higher than the untreated durian peel. The pretreatment liquor and biomass hydrolysate were analyzed by Gas Chromatograph-Mass spectrometer (GC-MS), and fermentation inhibitors, i.e. acetic acid, furfural, and furan methanol, were identified in those fractions. Due to pretreatment at the optimal condition, a higher yield of reducing sugar was observed, and the production of ethanol from the pretreated biomass was 5.70 ​g/L (equivalent to 87.43% of theoretical yields). These findings demonstrated the potential of using durian waste in the biorefinery concept to achieve a concept of the green economy.     

Theoretical and experimental study of IR spectra of large phenol-acetylene clusters,Ph(Ac)n for 8 ≤ n ≤ 12

This work reports a combined theoretical and experimental study on large phenol-acetylene clusters, Ph(Ac)_n, 8 ​≤ ​n ​≤ ​12, extending our earlier work on the smaller clusters [Singh, G.; Nandi, A.; Gadre, S. R.; Chiba, T.; Fujii, A. J. Chem. Phys. 2017, 146, 154303]. Several trial cluster geometries are generated using the molecular electrostatic potential (MESP) for placing additional acetylene moieties, followed by geometry optimization at B97D/aug-cc-pVDZ level theory. The infrared spectra of energetically low-lying (within 0.5 ​mH window) isomers of the clusters are calculated and averaged. The O–H stretching band shows two peaks due to the presence of energetically close isomers differing in the arrangement of acetylenes around the O–H group. The acetylenic C–H stretching band appears around 3260 ​cm⁻¹. The C–H band shows a red shift of about 3 ​cm⁻¹ on going from n ​= ​8 to 12. Moderately size-selected IR spectra of Ph(Ac)_n (n ​= ​~10 and ~13) prepared by a supersonic jet expansion are measured for the acetylenic C–H region by infrared-ultraviolet double resonance spectroscopy combined with time-of-flight mass spectrometry. The observed spectral features are in agreement with the trends of the frequency shift and asymmetric line shape of the C–H stretch band predicted by the theoretical calculations.     

Ultrasonic investigation of molecular interaction of thyroxine and anti-tuberculosis drugs and DFT studies

The strength of molecular interaction between thyroxine hormone (THY) and two widely used anti-tuberculosis (ATB) drugs, ethambutol(ETH) and rifampicin(RIF) is assessed through ultrasonic at various blend compositions of the hormone and drugs. Ultrasonic study is carried out at three different temperatures (303 ​K, 310 ​K and 313 ​K). The trend in acoustical properties with blend ratio is used to establish the molecular interaction between thyroxine and ATB drugs. The main aim of this study is to identify the blend ratios and the temperature at which the hormone-drug interaction is significant in aqueous medium. DFT analysis is carried out to understand the type of interaction. The results obtained in DFT analysis of the complexes of thyroxine and drug molecules support the experimental observations. Both studies suggest that THY-RIF interaction is stronger than ETH-THY interaction.     

Process intensification for synthesis of triglycerides of capric acid using green approaches

The present research focuses on intensified synthesis of tricaprin by esterification reaction between capric acid and glycerol catalysed by dry amberlyst-15 using ultrasonication approach. Effect of several reaction conditions like molar ratio, reaction temperature, and amberlyst-15 loading on the rate of conversion has been studied. Effect of ultrasonic conditions like duty cycle and irradiation time on the intensified synthesis is investigated. Recyclability of amberlyst-15 is studied to make process more economical. It is investigated that the optimum reaction conditions which gave maximum conversion of 95% were molar ratio of capric acid: glycerol as 3:5, reaction temperature 90 ​°C, 4% amberlyst −15 loading. It was further investigated that ultrasonic conditions which gave intensified synthesis were 70% duty cycle and irradiation time of 120 ​min. The ultrasonic assisted process was compared with conventional synthesis. Conventional synthesis gave 30% yield in 120 ​min and 82% in 18 ​h. Amberlyst-15 was successfully reused for 13 cycle without any change in the conversion (%) of reaction.     

Synthesis of new reactive dyes containing commercial UV-absorbers with enhanced simultaneous dyeing and anti-UV properties for cotton fabric

Two new reactive anti-UV dyes were synthesized based on two commercial UV-absorbers, ethyl 4-aminobenzoate for dye 1 and 4-aminobenzophenone for dye 2, which were incorporated in a structure modified from commercial reactive dye CI Reactive Red 198 (dye 3). Optimum exhaustion and total fixation values were achieved at 80 ​g/l sodium sulphate for dye 1 and 60 ​g/l sodium sulphate for dye 2, 20 ​g/l sodium carbonate at 70 ​°C for dye 1 and 80 ​°C for dye 2 and 60 ​min fixation time for both dyes. The two new reactive dyes exhibited higher dyeing properties and UPF values than the commercial reactive dye over all the dye concentrations studied. The new reactive dye 1 achieved the highest exhaustion, total fixation and UPF values. The fastness properties obtained for all the dyeings ranges from good to excellent.     

Research article green synthesis of zirconium oxide nanoparticles (ZrO2NPs) using Helianthus annuus seed and their antimicrobial effects

Monoclinic Zirconia (ZrO₂NPs) nanoparticles were successfully prepared by non-toxic and low-cost production using green synthesis analysis from the methanolic extract of Helianthus annuus (sunflower) seeds as the reducing agent. Mechanism of the chemical reaction has shown the reduction and which confirmed the formation of nanoparticles via chemical bonding in the IR spectrum at 502-498 ​cm^-1 ZrO₂ nanoparticles were characterized as sharp peak at 275 ​nm in the UV-Vis spectrum with 3.7eV in photon energy bandgap, it confirms the monoclinic crystal structure, as well as x-ray diffractometry, reveals zirconia crystallite is 40.59 ​nm. The internal morphology of crystal structure is exhibited by Scanning Electron Microscopy (SEM), and Transmission Electron Microscope (TEM). The stability of nanoparticles is represented in terms of zeta potential (-9.32 ​mV) and particle size distribution (~331 ​nm). Biosynthesized ZrO₂NPs were indicated as superior antimicrobial activity for biomedical applications.     

Microwave-assisted synthesis of ethyl laurate using immobilized lipase: Optimization,mechanism and thermodynamic studies

Microwave-assisted synthesis of ethyl laurate using lauric acid and ethanol catalyzed by Fermase CALB has been investigated. The effect of operating parameters like molar ratio (lauric acid: ethanol), enzyme loading, temperature, and molecular sieves was systematically studied. A maximum conversion of 98.2% was obtained in 10 ​min compared to the conventional method, where the reaction required 4 ​h to achieve 92.4% conversion. The optimum parameters for the microwave-assisted synthesis were 1:2 ​M ratio of lauric acid to ethanol, 45 ​°C temperature, 1.8% (w/w) enzyme amount, 1.5% (w/w) molecular sieves. The enzyme lipase was reused for up to seven successive cycles under microwave irradiation. The thermodynamic study was carried out to determine various thermodynamic parameters for the reaction. The esterification mechanism was proposed, and the impact of microwave irradiation on the immobilized enzyme after several reuse was studied by scanning electron microscopy.     

A molecular docking study of potential inhibitors and repurposed drugs against SARS-CoV-2 main protease enzyme

COVID-19 has affected millions of people. Although many drugs are in use to combat disease, there is not any sufficient treatment yet. Having critical role in propagation of the novel coronavirus (SARS-CoV-2) works Main Protease up into a significant drug target. We have performed a molecular docking study to define possible inhibitor candidates against SARS-CoV-2 Main Protease enzyme. Besides docking Remdesivir, Ribavirin, Chloroquine and 28 other antiviral inhibitors (totally 31 inhibitors) to Main Protease enzyme, we have also performed a molecular docking study of 2177 ligands, which are used against Main Protease for the first time by using molecular docking program Autodock4. All ligands were successfully docked into Main Protease enzyme binding site. Among all ligands, EY16 coded ligand which previously used as EBNA1-DNA binding blocker candidate showed the best score for Main Protease with a binding free energy of −10.83 ​kcal/mol which was also lower than re-docking score of N3 ligand (−10.72 ​kcal/mol) contained in crystal structure of Main Protease. After analyzing the docking modes and docking scores we have found that our ligands have better binding free energy values than the inhibitors in use of treatment. We believe that further studies such as molecular dynamics or Molecular Mechanic Poisson Boltzmann Surface Area studies can make contribution that is more exhaustive to the docking results.     

Antioxidant activity of a polysaccharide from Dictyophora indusiata volva and MECC analysis of its monosaccharide composition

In this paper, a crude polysaccharide (PDI) was extracted from D. indusiata volva. The antioxidant activities of PDI were examined by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, hydroxyl radical and ABTS radicals scavenge assay. The results showed that PDI had antioxidant activities in all these assays, indicating that it could be used as an antioxidant. Then a rapid and highly efficient micellar electrokinetic capillary chromatography (MECC) method coupled with diode array detector was developed to determine the monosaccharides composition of the polysaccharide sample. The optimum conditions were as follows: 20 ​mM borate (pH ​= ​9.3) and 15 ​mM SDS as the electrophoresis medium, the separation temperature was 20 ​°C. Under these conditions, monosaccharides could be separated within 8 ​min. The polysaccharide of the volva was mainly composed of glucose, mannose, galactose and arabinose.     

Study of the influence of nanoparticles on the behavior of composite materials

The objective of this work is to study the influence of additives of multi-walled carbon nanotubes (MWCNT) and silica nano-powder (SiO₂) on the mechanical behavior of epoxy resin. Different volume fractions of MWCNT and SiO₂were added. Mechanical characterization by tensile, three-point bending and Charpy tests were carried out. The experimental results show an increase in the mechanical performance of the mixtures (MWCNT ​+ ​epoxy), (SiO₂ ​+ ​epoxy) up to 2% of additive. Beyond this value, a degradation of performance was observed. The addition of MWCNT gives better results when compared to the addition of SiO₂. K_IC-K_CV correlations were made using empirical formulas to estimate the critical stress intensity factor K_IC from the impact energy of the Charpy test.Unfortunately, this estimation does not provided a promising results, but other optimization methods were used to fit these empirical models to the behavior of our nanocomposites for which a good estimate was obtained after fitting these empirical models for SiO₂.