Presence Of Stannic Chloride Research Articles

Tin (IV) chloride catalysed synthesis of di(indolyl)methanes during electrophilic substitution of indoles and 2-methyl indoles

An efficient methodology has been developed for the synthesis of di(indolyl)methanes in moderate to good yields during the study of the reactions of indole and 2-methyl indole using a series of aliphatic ketones in the presence of stannic chloride. It appears worth mentioning that with 2-methyl indole and acetone and ethyl methyl ketone the highly “elusive” indolylcarbinols, the postulated intermediates in the synthesis of di(indolyl)methanes, have been isolated.

Pharmacoscintigraphic evaluation and antidiabetic efficacy of gliclazide-loaded 99mTc-labelled mucoadhesive microspheres

BackgroundThe current study was carried out to evaluate the possible application of Musa balbisiana starch in formulation of mucoadhesive microsphere for oral delivery of gliclazide (GLZ). The study objective was to improve the oral bioavailability along with prolongation of its duration of action for a better glycaemic control. Ionic gelation technique was employed in formulating the dosage form. Optimization of the batches was carried out by response surface methodology using 32 full factorial designs. The microsphere prepared was characterized for several parameters along with its in vitro release study. The gastrointestinal transit of the optimized batch of prepared microspheres after oral administration was studied in rabbits by using the gamma scintigraphy technique utilizing 99mTc as the labelling agent in the presence of stannous chloride. Also, the optimized batch was studied for its pharmacokinetic parameters. Moreover, the antidiabetic efficacy of the prepared microsphere was evaluated in rats by using the streptozotocin (STZ)-induced diabetic model.ResultsThe factorial design experiment resulted in an optimum formulation coded as F8. The compatible nature of the drug and excipient was revealed from FTIR, DSC and IST studies. The scanning electron micrographs also showed the occurrence of spherical microspheres having a smooth surface. The in vitro release study provided an evidence of an initial burst effect that was followed by a prolong release phase. The pharmacokinetic parameters justified the ability of the prepared dosage form in sustaining the drug release with a 2.7-fold enhancement in drug bioavailability. The images obtained during the gamma scintigraphy study suggested the gastro-retentive nature of the dosage form with the gastro-retentive ability for more than 4 h. Also, the pharmacodynamics study carried out in diabetic rat model confirmed about the better efficacy of the dosage form in lowering the elevated blood glucose level.ConclusionThe overall study data provide valuable information about the potential of this banana starch in formulation of a mucoadhesive dosage form that can be used for enhancement of bioavailability of drug-like gliclazide which in turn can provide a beneficial effect in the management of diabetes.

Synthesis and characterization of lignin-poly lactic acid film as active food packaging material

ABSTRACT The present work describes the synthesis, characterisation and antimicrobial activity of lignin-polylactic acid (PLA) blended film. Film was prepared using co-polymerisation reaction of lignin and lactic acid in the presence of stannous chloride as a catalyst and poly(vinyl alcohol) to get the uniform film. The properties of the film was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA), respectively. The lignin-PLA film demonstrated a significant decrease in swelling ratio and tensile strength in contrast to PLA film. SEM analysis revealed proper blending of lignin into PLA matrix with slightly rough surface. Film was thermostable and amorphous in nature as confirmed from the thermal study and XRD analysis, respectively. Further, significant improvement was observed in antimicrobial activity and biodegradability of PLA film after addition of lignin, which suggest the putative application of lignin-PLA film as the food packaging and mulch film materials.

Imaging of the third gasotransmitter hydrogen sulfide using 99mTc-labeled alpha-hydroxy acids

IntroductionHydrogen sulfide (H2S) defined as the third gasotransmitter after nitric oxide (NO) and carbon monoxide (CO) is an important mediator of various physiological functions. Although various H2S-imaging techniques using fluorescence and luminescence have been developed, only one radionuclide imaging using 64Cu-labeled cyclen complex was reported. Thus, we tried to develop 99mTc-labeled H2S imaging agents. MethodsVarious α-hydroxy acids such as glycolate, L-lactate, D-lactate, D-gluconate, D-glucoheptonate, D-glucuronate, D-glucarate, and citrate were labeled with 99mTc in the presence of stannous chloride. The labeled compounds were incubated with 0.2 mM of NaHS, and reactive sulfur species and then analyzed by ITLC/normal saline to detect the formation of insoluble complex. Matrigels containing various concentrations of NaHS were xenografted on the shoulder of normal mice, and an imaging study was performed after intravenous injection of [99mTc]Tc-gluconate. We also obtained autoradiography image of a rat brain with a temporary brain ischemia after intravenous injection of [99mTc]Tc-gluconate. Results[99mTc]Tc-gluconate showed the highest formation of insoluble complex (87.8 ± 3.6%) after incubation with 0.2 mM NaHS. The other reactive species such as glutathione, cysteine, sulfite, sulfate, thiosulfate, and NO did not form insoluble complex representing the reaction being specific to H2S. The Matrigel containing 2 μmol NaHS showed uptake of [99mTc]Tc-gluconate, which proved the feasibility as the specific H2S imaging agent in vivo. Temporary ischemic lesion of rat brain showed high radioactivity accumulation representing the feasibility as endogenous H2S imaging agents. ConclusionWe proved that 99mTc-labeled α-hydroxy acid especially [99mTc]Tc-gluconate is a novel endogenous H2S imaging agent, which might contribute to study and diagnosis of various diseases related with inflammation and hypoxia.

Validation and analysis of thiram, a dithiocarbamate, as CS2 from soybean (Glycine max) samples on GC–MS

A method was validated for the estimation of dithiocarbamates in soybean leaf, pod, seed, oil and in soil. Method involves acid hydrolysis and reduction of dithiocarbamates to carbon disulfide in the presence of stannous chloride and hydrochloric acid. Thiram was spiked in the samples at the levels of 0.5, 2.5 and 5.0 µg g−1 and estimated as carbon disulfide on gas chromatograph coupled to single quadrupole (GC–MS) by monitoring m/z 76 (quantitation ion). Retention time of carbon disulfide was 2.119. All method validation parameters like linearity, accuracy and precision were within the acceptable range as per SANTE (in European Union Guidance document on analytical quality control and method validation procedures for pesticide residues analysis in food and feed. Document No. SANTE/11945/2015, 2015). The linearity, expressed as correlation coefficient, was 0.997. Accuracy was expressed as percent recovery. The recovery ranged from 87 to 102% in soybean leaf, 81–98% in soybean pod, 83–113% in soybean seed, 85–109% in soybean oil and 75–109% in soil at different fortification levels. Precision, expressed as relative standard deviation, ranged from 0.1 to 0.11 in various soybean samples. Limit of quantitation (LOQ) was 0.32 µg g−1 for soybean leaf, 0.18 µg g−1 for pod, 0.19 µg g−1 for seed and 0.1 µg g−1 for oil and soil. To our knowledge, this is the first report describing the extraction and analysis of thiram, a dithiocarbamate (DTCs) from soybean (oilseeds and oil). The method described here can be extended for the estimation of DTCs in other oilseeds and oils.

Formulation and Biodistribution of 99mTc-Dacarbazine, a Radioligand for Neoplasm Imaging

A method for preparing 99mTc-Dacarbazine, a potential cancer diagnostic agent, was developed. The method is based on direct labeling of Dacarbazine with 99mTc in the presence of stannous chloride as reducing agent. The reaction conditions were optimized to obtain the radiochemical yield of 99mTc-Dacarbazine higher than 90%. The biodistribution of 99mTc-Dacarbazine in normal and tumor-bearing Albino Swiss mice was studied. 99mTc-Dacarbazine has a high tumor affinity and shows promise for cancer imaging. Quantitative relationship between the optimized structures and computed molecular properties related to Dacarbazine binding sites was analyzed using molecular modeling.

Chemometrics-assisted cross injection analysis for simultaneous determination of phosphate and silicate

ABSTRACTThis work presents a novel method for simultaneous spectrophotometric determination of phosphate and silicate by using a cross injection analysis (CIA) coupled with the use of partial least squares (PLS) for data evaluation. The detection principle is based on the well-known ‘molybdenum blue’ method. The molybdate ions in the presence of stannous chloride in acidic medium give phosphomolybdenum blue and silicomolybdenum blue as products. In this work, all the liquids, including sample and reagents were simultaneously introduced into a CIA platform by using two peristaltic pumps for controlling the x-channel and y-channel flow which was automatically manipulated by using in-house control board. Crossflow provides sufficient mixing inside the platform prior detection of the absorption spectra of blue complexes in the wavelength of 400–900 nm. Since spectra of the blue colour product of phosphate and silicate are resemblant, these two analytes therefore reciprocally interfere with one another. This results in difficulty in simultaneous analysis of phosphate and silicate. In this work, PLS was utilised as assistor of CIA system for simultaneous analysis of phosphate and silicate using molybdenum blue reaction without using any modification of reagents and addition of selective masking agent. The calibration ranges are 0.1–6 mgP L−1 and 5–100 mgSi L−1 for phosphate and silicate, respectively. By using CIA coupled with PLS for data evaluation, the analysis of two analytes was achieved within 1.5 min with only single injection. The developed system was applied to natural water samples and the system was validated with the conventional methods. By statistical paired t-test, there was no evidence of significant difference at 95% confidence level (tstat = 2.28, tcritical = 2.31 and tstat = 0.62, tcritical = 2.31 for phosphate and silicate, respectively). This implied that the chemometrics-assisted CIA system was successfully developed for simultaneous spectrophotometric determination of phosphate and silicate.

Hydroxyapatite nanoparticles: preparation, characterization, and evaluation of their potential use in bone targeting: an animal study.

Hydroxyapatite is used as a drug-delivery system for bone therapy applications because of its biocompatibility, bioactivity, and osteoconductive properties. In addition, hydroxyapatite nanoparticles (HApN) might be used as a theranostic probe. The aim of this study was to prepare and characterize hydroxyapatite mesoporous nanoparticles, and radiolabel these nanoparticles with technetium-99m (Tc). Moreover, biodistribution studies were carried out in healthy mice. HApN were synthesized and characterized. Tc-HApN was prepared by adding Tc-pertechnetate to a dispersion of HApN in the presence of stannous chloride. Radiochemical purity and in-vitro stability were determined. The circulation time of Tc-HApN was determined by measuring blood radioactivity in healthy mice. In addition, biodistribution studies were carried out in healthy mice at 1 and 4 h after injection. Tc-HApN showed high radiochemical purity (98.7±0.2%) and in-vitro stability until 24 h. Tc-HApN levels in blood decreased in a biphasic manner, with an α half-life of 1.8 min and a β half-life of 126.9 min. High uptake was achieved in the liver and spleen because of the macrophage uptake. Furthermore, bone uptake was higher than that of the surrounding muscle, resulting in high bone-to-muscle ratios. HApN were synthesized successfully with suitable characteristics for in-vivo applications. Tc-HApN was prepared and showed high stability. Tc-HApN presented increasing bone uptake over time, showing a higher affinity to bone tissues in contrast to surrounding muscle. The present results, together with further studies, may indicate a potential application of HApN as a nanocarrier for bone diseases.

Conversion of Paper Waste Into Bioplastic (Poly‐Lactic Acid)

SummaryThe broadly apposite bioplastic, poly lactic acid was synthesized by using deinked paper waste as substrate, fermentation with Saccharomyces cerevisiae under controlled laboratory conditions followed by condensation polymerization. The substrate was initially subjected to acid hydrolysis followed by alkali neutralization to attain an ideal neutral pH for the growth of Saccharomyces cerevisiae. At regular intervals the amount of reducing sugar present in the samples were tested using 2,4‐dinitrosalicyclic acid (DNS) method and the amount of sugar that was metabolized to alcohol and lactate were estimated using cerric ammonium nitrate and ρ‐hydroxy biphenyl method respectively. The lactic acid extract was concentrated using a rotary vacuum evaporator and the amount was determined spectrophotometrically. The concentrated extract was used for polymerization in the presence of stannous chloride. This resulted in the production of white amorphous wafers. Polymerization trial with stannous chloride was done with 1 ml of purified extract with 0.1 g of stannous chloride.

Technetium-99m-labeled doxorubicin as an imaging probe for murine breast tumor (4T1 cell line) identification.

Early diagnosis of malignant tumors is essential to successfully plan a radical and curative approach. In this study we describe the direct radiolabeling of doxorubicin (DOX) at physiological pH to identify murine breast tumor (4T1 cells)-bearing BALB/c mice. Technetium-99m (99mTc) DOX was prepared by adding 99mTc-pertechnetate to a PBS (pH 7.4) solution containing DOX in the presence of stannous chloride. Radiochemical purity and in-vitro stability were determined. The circulation time of 99mTc-DOX was determined by measuring blood radioactivity in healthy animals. Scintigraphic images and biodistribution studies were carried out in tumor-bearing mice at 1, 4, and 8 h after injection. The 99mTc-DOX complex showed high radiochemical purity (99.27 ± 0.34%) and in-vitro stability until 8 h. Tc-DOX levels in blood declined in a biphasic manner, with an α half-life of 4.5 min and a β half-life of 277.2 min. High uptake was achieved in kidneys, liver, and spleen, because of the drug elimination routes. Moreover, tumor uptake was higher than that of control tissue, resulting in high tumor-to-muscle ratios. DOX was successfully labeled with 99mTc-pertechnetate and showed high stability. Biodistribution and scintigraphic studies indicated high tumor-to-muscle ratios in breast tumor-bearing BALB/c mice. These results suggested the feasibility of 99mTc-DOX as a functional agent in tumor diagnosis.

English

Schwartzia brasiliensis (Marcgraviaceae) is a native Brazilian shrub species with neotropical distribution in shoal environments. Recent studies have revealed its medicinal potential for some human diseases; therefore, this study aimed to evaluate the genotoxic and antigenotoxic potential of extracts and fractions obtained from different organs of S. brasiliensis. To accomplish this, plant extracts at different concentrations (25, 125 and 250 µg/ml) were incubated with plasmid DNA, either alone, or in the presence of stannous chloride as a positive control. Samples were then examined to detect any plasmid strand breaks or the absence of such breaks, which would indicate protection of these molecules against stannous chloride-induced lesions. Methanol and aqueous extracts of leaves and stems showed the ability to withstand the effects of stannous chloride in that no DNA damage was observed. Moreover, no other extracts or fractions used in the experimental conditions assayed resulted in DNA damage. These findings suggest that S. brasiliensis has antigenotoxic properties, indicating, in turn, that its biological activities deserve further study given the medicinal relevance of this plant.   Key words: Medicinal plant, Marcgraviaceae, stannous chloride, flavonoids.&nbsp

Study the effect of ammonia post-treatment on color characteristics of annatto-dyed textile substrate using reflectance spectrophotometery

This research is aimed to study the influence of ammonia after-treatment on color behavior in wool yarns dyed with annatto extract. The dyeing was carried out using 15% (o. w. f.) dye concentration in presence of stannous chloride as a mordant and then treated with different percentages of ammonia solution. At the same time, color strength, CIE-Lab values and fastness properties of all dyed woolen yarns were also assessed. It was concluded that, in all cases after treatment with ammonia caused a decrease in lightness (L*) values, there was less lightness in the red hue of the wool yarns with the increase of ammonia percentage in solution. The K/S value of annatto dyed wool was found to increase after treated with ammonia. In addition, it was also observed that dyed wool yarns after post-treatment with ammonia did not return to their original color on acidification.

Modification of polysulfone with pendant carboxylic acid functionality for ultrafiltration membrane applications

p-Carboxyphenoxymethyl polysulfone (CPMPSF) was synthesized in two steps: (i) chloromethylation of polysulfone (PSF) by in situ generated chloromethyl radical in presence of stannic chloride in tetrachloroethane and (ii) reaction of chloromethylated PSF with p-hydroxybenzoic acid in presence of potassium carbonate in dimethylformamide. The structures of the modified PSFs were confirmed by elemental analysis, IR, 1H–NMR and \(^{{13}}\)C–NMR techniques. The PSF and CPMPSF based ultrafiltration membranes were prepared according to phase–inversion process using water as nonsolvent at 4° and 15 °C, employing casting dope having different amounts of polymer (PSF or CPMPSF), polyvinylpyrrolidone (PVP) and solvent, dimethylformamide (DMF). The membranes were characterized for their pore size, pure water flux and flux and rejection for the permeation of different molecular weight poly(ethylene glycol) (PEG) solutions and sodium chloride (NaCl) solution. The pore radius of the CPMPSF membrane which was prepared without PVP in the casting dope was about 222 Å, whereas, that of the membrane prepared in the presence of PVP (6 wt%) in the casting dope was about 124 Å. For the PSF membranes, pore radii were 80 Å (without PVP) and 176 Å (with PVP 6 wt%). The CPMPSF-based membranes exhibited higher flux and rejections for PEG and NaCl solutions, as compared to the PSF membranes, due to the presence of hydrophilic carboxylic acid group. The CPMPSF membrane exhibited about 48% rejection of NaCl when tested for 5000 ppm feed solution at 400 psi.

Synthesis and Characterization of Starch Graft Biodegradable Polyester and Polyesteramide by Direct Polycondensation

Starch graft poly(lactic acid-co-glycolic acid) (St-g-PLGA) and poly(lactic acid-co-glycolic acid-co-ϵ-caprolactam) (St-g-PLGC) copolymers were prepared by direct polycondensation from soluble starch, lactic acid, glycolic acid and ϵ-caprolactam in presence of stannous chloride (SnCl2 · 2H2O). The structure of the copolymers was clarified by NMR spectroscopy, and the thermal properties were investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The results indicated that the glass transition temperature (T G ) increased when the contents of ϵ-caprolactam decreased. Moreover, The mechanical properties examination demonstrated that tensile strength and bending strength changed from 32.3 Mpa and 69 Mpa to 24.2 Mpa and 28 Mpa.

Phosphate functionalized and lactic acid containing graft copolymer: synthesis and evaluation as biomaterial for bone tissue engineering applications

Polyvinyl alcohol (PVA) and polylactic acids (PLA) are biocompatible materials possessing some inherent contrasting limitations which have reduced the scope of their individual applicability. Specifically, overcoming strong hydrophobicity and introducing chemical groups for biofunctionalization are unmet challenges for PLA whilst chemical endeavors to render adequate aqueous stability and cell adhesion properties to PVA have not produced completely intended results. Objective of the present work is to explore synthesis of a graft polymer as an approach towards coupling biofunctional groups with PLA materials. In a two-step reaction, PPVA (phosphorylated polyvinyl alcohol or PVA pre-functionalized with phosphate) is esterified with lactic acid followed by polymerization into PLA in presence of stannous chloride as catalyst to obtain phosphorylated polyvinyl alcohol-graft-polylactic acid (PPVA-g-LA) copolymer. Product is characterized by nuclear magnetic resonance, X-ray diffraction, and thermogravimetric analysis. PPVA-g-LA shows an increase in uniaxial elongation compared to parent PPVA under condition of tensile loading. The graft copolymer also exhibits higher water contact angles compared to PPVA, but a more hydrophilic surface compared to PLA. Culture of MG-63 cells on solvent cast films of polymers demonstrates that PPVA-g-LA as a cell substrate can significantly (p < 0.05) improve proliferation and differentiation of cells compared to PPVA substrate whereas in comparison to PLA can significantly ameliorate osteoblast function of cultured cells. Overall, results illustrate the feasibility of PVA to act as a carrier for biofunctional agents to be coupled to lactic acid-based biomaterials with subsequent improvement in cell response on the polymers. In this attempt, it also affords materials with tunable surface or bulk properties of relevance for tissue engineering applications.

Efficient Synthesis of 8-Methoxy-3,4-dihydro-2H-1-benzopyran-3-ol

The article reports a practical, simple, and inexpensive procedure for the synthesis of 8-methoxy-3,4-dihydro-2H-1-benzopyran-3-ol (1). 2-Methoxy phenol on treatment offers the oxirane compound, which undergoes ring cleavage under acidic conditions to give a chlorohydrin, which on acylation and cyclization in the presence of stannic chloride followed by hydrolysis of the acetyl group, yields the desired compound (1).

ChemInform Abstract: Platinum-Catalyzed Asymmetric Hydroformylation of Olefins with (-)- BPPM/SnCl2-Based Catalyst Systems.

Three complexes of Pt(II) containing the chiral ligands 1-(tert-butoxycarbonyl)-(2S,4S)-2-[(diphenylphosphino)methyl]-4-(dibenzophospholyl)pyrrolidine, 1-(tert-butoxycarbonyl)-(2S-4S)-2-[(dibenzophospholyl)methyl]-4-(diphenylphosphino)pyrrolidine, and 1-(tert-butoxycarbonyl)-(2S,4S)-4-(dibenzophospholyl)-2-[(dibenzophospholyl)methyl]pyrrolidine were synthesized. Asymmetric hydroformylation of styrene was examined with use of platinum complexes of these three ligands, as well as Pt II BPPM, in the presence of stannous chloride as catalyst

Single-pot synthesis: Plant mediated gold nanoparticles catalyzed reduction of methylene blue in presence of stannous chloride

Gold nanoparticles of about 20 nm in diameter and having λ max at 542 nm is prepared by addition of HAuCl 4 solution to green tea leaves extract at room temperature. The synthetic route does not involve any toxic chemicals or organic solvent and it is totally aqueous phase synthesis; so it is a green approach. The synthesized nanoparticles were used as a catalyst for the reduction of methylene blue dye in the presence of Sn(II) in aqueous and micellar media and the rate of reduction is determined by measuring the decrease in absorbance of the dye at 663 nm spectrophotometrically. The rate of reduction follows the order Rate SDS > Rate CTAB > Rate water. The activation energy as determined using Arrhenius equation for the reaction catalyzed by gold nanoparticles is 38.42 kJ mol −1 and the slow reaction rate of uncatalyzed reaction has been manifested through larger activation energy of about 88.13 kJ mol −1.

ChemInform Abstract: Copper(II)/Tin(II) Reagent for Allylation, Propargylation, Alkynylation, and Benzylation of Diselenides: A Novel Bimetallic Reactivity.

Reactions of allyl, propargyl, benzyl, and alkynyl bromides with diorganodiselenides in the presence of stannous chloride and catalytic cupric halide result in the formation of corresponding unsymmetrical selenides in good to excellent yields via a novel dicopper(selenophenyl) intermediate.

The rabbit biodistribution of a therapeutic dose of zoledronic acid labeled with Tc-99m

The aim of the present study was to label a therapeutic dose of zoledronic acid (ZOL) with Tc-99m, evaluate its in vitro stability and compare its biodistribution to 99mTc-methylene biphosphonate (99mTc-MDP) in normal rabbits. Preparation of 0.50mg of 99mTc-ZOL was carried out by the reduction of 99mTc-pertechnetate in the presence of stannous chloride. The radiolabeling efficiency was found to be greater than 99%. The labeled complex was stable at least up to 6h at room temperature determined by paper chromatography. 99mTc-ZOL and 99mTc-MDP were administered intravenously to the rabbits for scintigraphic studies. Between 99mTc-ZOL and 99mTc-MDP, there were no significant differences in the ratios of femur/BG and lumbar vertebrae/BG, whereas epiphysis/BG and the kidney/BG ratios of 99mTc-MDP were higher than 99mTc-ZOL at the static studies.