Ultrasonication-Assisted Synthesis of a d-Glucosamine-Based ß-CD Inclusion Complex and Its Application as an Aqueous Heterogeneous Organocatalytic System.

For the first time, an inclusion complex has been crafted between a carbohydrate-based molecule and a ß-cyclodextrin (CD) hydrophobic cavity for asymmetric catalytic applications. This novel d-glucosamine-based inclusion compound has been synthesized in high yields using an innovative and proficient acoustic cavitation technology and well characterized using various techniques, such as infrared spectroscopy, nuclear magnetic resonance spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, scanning electron microscopy, and other spectroscopic techniques. It was observed that the inclusion of a d-glucosamine derivative into the hydrophobic cavity of ß-CD increased its surface area and thermal stability. This catalytic system worked well in water for the direct aldol reaction to afford the products in excellent yields with high diastereo- and enantioselectivities.

Nanoemulsions as an effective medium for encapsulation and stabilization of cholesterol/ß-cyclodextrin inclusion complex.

BACKGROUND: Inclusion complex formation between ß-cyclodextrin (ß-CD) and suitable guest molecules such as cholesterol (Ch) has regularly been exploited to design self-assembled structures. In the present study an effective nanoemulsion medium (lecithin/Tween 80/ethyl oleate/water) was selected for solubilizing and stabilizing Ch and Ch/ß-CD inclusion complex. Phase solubility, spectroscopic, thermodynamic, Z-average diameter and morphological analyses were conducted. RESULTS: Phase solubility data analysis demonstrated an increase in Ch solubility at low ß-CD concentrations (0.01-0.35 mmol L(-1) ). Transmission electron microscopy and Z-average diameter data indicated the spherical nature of the droplets and confirmed the formation of nanoemulsions with an average size of less than 50 nm. The negative value of ΔG obtained during analysis further indicated that the binding was spontaneous in nature. CONCLUSION: Primarily, this research demonstrates the use of nanoemulsions as a medium in food matrices, instead of water, for hosting Ch in ß-CD.

Quantification of penoxsulam in soil and rice samples by matrix solid phase extraction and liquid-liquid extraction followed by HPLC-UV method.

The paper exploits the development of novel, simple and sensitive methodology involving matrix solid phase dispersion (MSPD) and the comparison of MSPD with liquid-liquid extraction (LLE) for the evaluation of residual penoxsulam in soil and rice samples. Extracted samples were analyzed by high-performance liquid chromatography (HPLC) with ultraviolet detector at 230 nm. Both methods were optimized, considering different parameters, and under optimum conditions, the mean recoveries obtained were in the range of 85-104 % for MSPD and 78.8-90.7 % for LLE. Precision values expressed as relative standard deviation (RSD) were ≤10 for MSPD and ≤15 for LLE. Linearity for penoxsulam was in the range of 0.01-20 µg mL(-1) with limits of detection and limits of quantification of 0.01 and 0.03 mg kg(-1), respectively.

Surface-Initiated Reversible Addition-Fragmentation Chain Transfer Polymerization (SI-RAFT) to Produce Molecularly Imprinted Polymers on Graphene Oxide for Electrochemical Sensing of Methylparathion.

A nonenzymatic redox-responsive sensor was put forward for the detection of methylparathion (MP) by designing globular nanostructures of molecularly imprinted polymers on graphene oxide (GO@MIPs) via surface-initiated reversible addition-fragmentation chain transfer polymerization (SI-RAFT). Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and small-angle X-ray scattering (SAXS) studies have confirmed the successful formation of receptor layers of MIPs on RAFT agent-functionalized GO sheets. The electrochemical signal with an amplified current response was attained because of the enhanced diffusion rate of ions at the interface provided by widening the pore size of the MIP film. The analytical response of GO@MIPs, validated by recording square-wave anodic stripping voltammetry (SWASV) at varying MP concentrations, followed the linear response between 0.2 and 200 ng/mL. Under optimized conditions, the sensor exhibited a limit of detection of 4.25 ng/mL with high selectivity over other interfering ions or molecules. The anti-interfering ability and good recovery (%) in food samples directed the use of the proposed sensor toward real-time monitoring and also toward future mimicking of surfaces.

Electrochemical detection of methyl parathion via a novel biosensor tailored on highly biocompatible electrochemically reduced graphene oxide-chitosan-hemoglobin coatings.

A quick electrochemical sensing tool by utilizing novel bioelectrode based on redox active protein hemoglobin (Hb) has been offered here for the determination of methylparathion (MP). The bioelectrode has been designed by immobilizing Hb on electrochemically reduced graphene oxide-chitosan (ERGO-CS/Hb/FTO) based biocompatible coatings. Fourier transform-infrared analyses (FTIR), field emission scanning electron microscopy (FESEM), UV-visible and electrochemical characterization reveal the successful grafting of ERGO-CS/Hb/FTO. A detailed impedimetric analysis shows low charge transfer resistance (RCT) and solution resistance (Rs) for the fabricated biosensor, thus pointing towards improved electrochemical performance and sensitivity. In-depth elucidation of redox analysis has been presented in terms of surface concentration of redox moiety (2.92 × 10-9 mol cm-2) and heterogeneous electron transfer rate constant (0.0032 s-1) which indicate enhanced surface coverage and better charge transfer properties of the proposed electrochemical biosensor. The sensor is equipped with a low limit of detection of 79.77 nM and a high sensitivity of 45.77 Acm-2 µM-1 with excellent reproducibility. The modified biosensor also offered its credibility towards detection of MP in vegetable samples with recovery (%) ranging from 94% to 101%. The designed biosensor hereby, evolves as a promising approach for the recognition of MP.

Mixed surfactant based microemulsions as vehicles for enhanced solubilization and synthesis of organoselenium compounds.

We exploited the added degree of compositional freedom provided by mixed AOT/lecithin surfactants in reverse isooctane microemulsion to demonstrate that a small amount of added lecithin significantly enhances the solubility of organodiselenides over that in AOT reverse isooctane microemulsions alone. Conductivity results show that the added lecithin significantly increases the solubility of four different organodiselenides and raises the temperature required to induce percolation. FTIR, (1)H NMR, and UV-visible techniques were utilized to gain insight into the interactions of organodiselenides, AOT and lecithin headgroups with water in the micellar core. The information obtained from these experiments was used to design a novel synthetic route for preparing 4-chloro-2-(naphthalen-2-ylselanyl) pyrimidine in reverse microemulsion.

Chitosan nanoparticles as a biocompatible and efficient nanowagon for benzyl isothiocyanate.

A plethora of evidences support the health benefits of a sulfur containing compound called Benzyl Isothiocyanate. However, its therapeutic application is limited due to its low solubility, poor stability and inadequate bioavailability. The problem has been worked upon and resolved by the synthesis of biodegradable nanoparticles using chitosan as the controlled delivery nanowagon. The prepared nanoparticles have been characterized using UV-visible absorption spectroscopy, IR spectroscopy, XRD, TGA, TEM and FE-SEM. Results reveal that loading of benzyl isothiocyanate into chitosan nanoparticles increases its solubility and stability. The maximum encapsulation efficiency was obtained to be 64.68±4.7% with slow and sustained release of 77.78% in 144h at pH5.5. Clear enhancement in the stability of benzyl isothiocyanate that is sensitive to ultraviolet light has been showcased after its encompassment in the cationic polymer. Further the biosafety of the fabricated system has been demonstrated by haemolysis and its interaction with biomolecules. The antimicrobial activity connotes that the prepared nanoparticles can act as a useful and safe carrier for the loading of benzyl isothiocyanate making it a promising formulation for biological applications in future.

Behavior of acetyl modified amino acids in reverse micelles: a non-invasive and physiochemical approach.

The well-characterized, monodisperse nature of reverse micelles formed by sodium bis-(2-ethylhexyl)sulfosuccinate/water/isooctane and their usefulness in assimilating compounds of varied interests have been exploited to investigate the effect of acetyl modified amino acids (MAA) viz., N-acetyl-L-glycine (NAG), N-acetyl-L-aspartic acid (NAA) and N-acetyl-L-cysteine (NAC), on the water pool and physiochemical properties. Non-invasive techniques such as FTIR and UV-vis absorption spectroscopy have been employed to analyze the interactions of MAA with core water and the AOT headgroup. The micropolarities on both sides of AOT interface have further been investigated by UV-vis absorption probes, methyl orange (MO) and methylene blue (MB). The dynamics of water and temperature induced percolation process have also been studied. The MAA molecules have been found to assist the process with the increase in water content where as a contrary behavior has been observed with the increase in temperature. Conductivity results have been further rationalized in terms of scaling equations, which delineate the dynamic nature of the percolation process. The results have also been analyzed in the light of activation energy of the percolation process and thermodynamics of droplet clustering.

Formulation and physiochemical study of α-tocopherol based oil in water nanoemulsion stabilized with non toxic, biodegradable surfactant: Sodium stearoyl lactate.

The unique properties such as high optical clarity, stability and enhanced bioavailability of nanoemulsion make them useful for food, cosmetic and pharmaceutical industries. In this work, sodium stearoyl lactate and Tween 80 surfactants were collectively used to fabricate alpha tocopherol based oil in water nanoemulsion using high energy ultrasonication method. The spherical nature of pure and drug loaded nanoemulsion has been confirmed with transmission electron microscopy (TEM). The influence of pH, dilution, surfactant concentration and ionic strength on average particle size of pure and nutraceutical (benzylisothiocyanate and curcumin) encapsulated emulsion was examined. The prepared emulsion exhibited good stability up to 90days in salt solution (50-200mM) and different pH conditions. The cumulative release % of benzylisothiocyanate and curcumin was found to be 50.29% in 36h and 89.15% in 150h respectively. The antioxidant activity of pure, benzylisothiocyanate, curcumin and cocktail (benzylisothiocyanate and curcumin) nanoemulsion was calculated with 2,2-diphenyl-1-picrylhydrazyl radical. The IC50 value of different antioxidant showed that benzylisothiocyanate nanoemulsion acted as better antioxidant as compared to pure and curcumin encapsulated nanoemulsion. Also the cell viability of pure nanoemulsion was found to be 24% on hep G2 cell. The effect of UV light irradiation on curcumin and benzylisothiocyanate stability was carried out in different solvent conditions (water/ethanol and nanoemulsion). The degradation of curcumin by the impact of UV light was successfully controlled by trapping in NEm.

Ultrasound processed nanoemulsion: A comparative approach between resveratrol and resveratrol cyclodextrin inclusion complex to study its binding interactions, antioxidant activity and UV light stability.

Resveratrol is a naturally occurring therapeutic molecule used for treatment of diseases caused by oxidative stress. This investigation elucidates the advantages of fabrication of size controlled resveratrol inclusion complex. This has been done by encapsulating resveratrol-cyclodextrin inclusion complex in a phospholipid stabilized nanoemulsion formulated by ultrasonication emulsification method. The prepared nanoemulsion has been compared with resveratrol encapsulated nanoemulsion system. The morphology of the resveratrol nanoemulsion and inclusion complex nanoemulsion have been observed using transmission electron microscopy with average size 20.41±3.41 and 24.48±5.70nm respectively. The nanoemulsion showed good loading and release efficiency. The radical diminishing potential of resveratrol and its inclusion complex has been compared in nanoemulsion. The effect of UV irradiation (365nm) on resveratrol in different solvent systems (ethanol, water and nanoemulsion) indicated that nanoemulsion prevents degradation of resveratrol. Efforts have also been made to explore the interactions between bovine serum albumin and resveratrol in nanoemulsion.

Physiochemical and cytotoxicity study of TPGS stabilized nanoemulsion designed by ultrasonication method.

The main aim of the present work was to prepare TPGS stabilized D-α-Tocopherol, lemon oil, tween-80, and water nanoemulsion by low cost and highly effective sonication method. The prepared nanoemulsion showed good stability for 60days at variable temperature conditions i.e. 4, 25 and 37°C. The tolerance of the prepared nanoemulsion to salt (50mM-500mM) and pH (pH 2-pH 7.4) was also studied. The morphology and droplet size of pure and quinine loaded nanoemulsion was characterized with transmission electron microscopy. The prepared formulation was transparent and the obtained average particle size ranged between 25nm and 35nm. The nanoemulsion was found to be non toxic. The cell viability study of pure nanoemulsion carried out on Hep G2 cells revealed that the cell viability was 100%. The formulation further exhibited high quinine loading and release capacity with cumulative release up to 76±2% and 65±2% at pH 7.4 and pH 5.5 respectively. The interaction between quinine and vitamins (riboflavin, thiamine and biotin) was also carried out (aqueous medium). The study revealed that riboflavin had strong interaction with quinine and vitamins vis-à-vis thiamine and biotin.

Encompassment of Benzyl Isothiocyanate in cyclodextrin using ultrasonication methodology to enhance its stability for biological applications.

The use of methodical and innovative sonication method has been explored for the fabrication of inclusion complex of Benzyl Isothiocyanate, a potential anticancer and -antimicrobial agent. The advancement involved investigation of inclusion behaviour, characterisation and an in-depth study of thermal and UV stability of Benzyl Isothiocyanate with cyclodextrins; ß-CD and hp-ß-CD. The sonication driven encompassment in cyclodextrins helped to overcome the hindrance of low solubility and high volatility. Investigations of physical and thermodynamic parameters using UV-visible spectroscopy, FTIR, XRD, TGA etc confirmed stability of inclusion complexes. Both ß-CD and hp-ß-CD based inclusion complexes retained the antimicrobial property of the free Benzyl Isothiocyanate, indicating their potential utility as antimicrobial agents. Haematological safety and cellular uptake data gives direction to in-depth analysis for its exploitation of anti-tumour activity.

Formulation of saponin stabilized nanoemulsion by ultrasonic method and its role to protect the degradation of quercitin from UV light.

The objective of the present study was to prepare quercitin (QT) loaded o/w nanoemulsion using food grade surfactants (saponin and tween 80). The prepared nanoemulsion) was stable up to 30 days. The average particle size of the nanoemulsion was 52 ± 10 nm. The formation of saponin stabilized nanoemulsion was confirmed by transmission electron microscopy. Quercitin (QT) trapped nanoemulsion showed higher stability on exposure to UV light (254 nm) as compared to water/ethanol system. The degradation rate was found to decrease from 9 ± 1%, 11 ± 1% at pH 7.4, 8.0 respectively as compared to 42 ± 2% in water/ethanol system. Attempt was also made to study the interaction of QT with two different bile salts (sodium cholate and sodium taurocholate). The free radical scavenging activity of DPPH quercitin and curcumin was compared in NEm media. The obtained IC50 value of quercitin, curcumin and ascorbic acid are 28.88 ± 1, 45.53 ± 2 and 51.51 ± 2 µM respectively. The values of binding constant for sodium cholate (NaC) and sodium taurocholate (NaTC) are 2.66 × 10(5) and 2.72 × 10(4) M(-1) respectively. Sodium cholate (NaC) was found to show strong interaction towards quercitin (QT) due to more electron density on oxygen atom of carboxylate ion.

Mixed anionic and zwitterionic surfactant based microemulsions as vehicles for solubilizing organodiselenides.

Spectral and physiochemical behavior of water/sodium bis-(2-ethylhexyl)sulfosuccinate (AOT)/isooctane (ME-I) and water/AOT+lecithin (LC)/isooctane (ME-II) microemulsions has been investigated in the presence of organodiselenides. It was found that the OH, CO and C-O-C FTIR stretching frequency of the formulated microemulsions change with the addition of organodiselenides. Interaction with Acridine Orange (AO) indicates organodiselenide presence at the interface. Estimates of the micropolarities of the microemulsions at different water contents were carried out in terms of an empirical polarity parameter E(T)(30). The values increase with the increase in omega = [H(2)O]/[surfactant]. The emission spectra of AO reveal the quenching capacities of the added organodiselenides. The temperature induced percolation process has also been studied. The results indicate a subsequent increase in solubilization of organodiselenide in ME-II as compared to ME-I.