In situ chlorpyrifos (CPF) degradation by Acrobeloides maximus: Insights from chromatographic analysis.

The objective of this study was to evaluate the efficiency of nematodes in zooremediation of chlorpyrifos (CPF), an organophosphate pesticide. The nematode population Acrobeloides maximus (A. maximus) was employed for bioremediation, converting CPF into non-toxic residues. Optimal growth conditions for mass production of A. maximus were achieved by maintaining a temperature of 25 °C, pH 8, and supplementing the culture medium with plant nutrients. The nematodes were then immobilized within sodium alginate beads. The efficacy of the degradation process was assessed using various analytical techniques, including UV-Visible spectroscopy, HPTLC, FTIR, and LC-MS, confirming the successful breakdown of CPF. The bioreactor demonstrated a complete degradation efficiency of CPF exceeding 99%. Additionally, LC-MS analysis was conducted to elucidate the degradation pathway based on the formation of intermediates. These results underscore the potential of A. maximus as a sustainable organism for addressing environmental contamination arising from CPF pesticide.

Visible light mediated synthesis of 1,3-diarylated imidazo[1,5-a]pyridines via oxidative amination of C-H catalyzed by graphitic carbon nitride.

Graphitic carbon nitride (g-C3N4) as a novel heterogeneous catalyst is employed for the visible light-mediated synthesis of the imidazo[1,5-a]pyridines via the oxidative amination of C-H bond at room temperature without the need for any additional solvent. Extensive characterization of the catalyst was performed using techniques such as FT-IR, PXRD, TGA, SEM and EDX analysis. The optimized conditions enabled the successful and expeditious conversion of a wide range of substrates to imidazo[1,5-a]pyridines in good yields; a notable advantage of this catalyst being recyclability, as it can be reused for up to five cycles without significant loss of activity. This feature makes it suitable for gram-scale synthesis of imidazo[1,5-a]pyridines. Additionally, this approach offers several benefits from a green chemistry perspective as affirmed by its favorable green chemistry metrics (GCM), including low process mass intensity (PMI), low E-factor, high atom economy (AE), and good reaction mass efficiency (RME) relative to existing protocols. In addition, chemical yield (CY), mass intensity (MI), mass productivity (MP) and optimum efficiency were also calculated. This environmentally friendly method offers multiple advantages and represents a significant advancement in the synthesis of imidazo[1,5-a]pyridines.

Green synthesis of silver nanoparticles using Adhatoda vasica leaf extract and its application in photocatalytic degradation of dyes.

The paper describes biogenic synthesis of silver nanoparticles (AgNPs) using Adhatoda vasica leaf extracts at room temperature. The prepared AgNPs were characterized by UV-visible spectroscopy, Fourier-transform infrared spectroscopy, powder X-ray diffraction, Energy dispersive X-ray (EDX), High Resolution Transmission Electron Microscope, Scanning Electron Microscopy and Thermogravimetric analyser. The bio reduction method is devoid of any toxic chemicals, organic solvents, and external reducing, capping and stabilizing agent. The synthesized AgNPs had spherical shape with particle size ranging between 3.88 and 23.97 nm and had face centered cubic structure. UV-visible spectral analysis confirmed the formation of AgNPs with a characteristic surface plasmon resonance band at 419 nm. The EDX pattern revealed the presence of elemental Ag in AgNPs. The prepared AgNPs were used for degradation of Amaranth, Allura red and Fast green in aqueous medium, with ≥ 92.6% efficiency within 15 min using 5 mg of AgNPs. The optical bandgap, Eg value of 2.26 eV for AgNPs was found to be effective for rapid photocatalytic degradation of all the three dyes. The degradation process was observed to follow pseudo first order kinetics.

Progress in appended calix[4]arene-based receptors for selective recognition of copper ions.

In the past two decades, there has been significant progress in the design and development of synthetic receptors for molecular recognition as they find application in the field of chemical, biological, medical, and environmental sciences. Synthetic receptors based on calix systems appended with fluorogenic and chromogenic groups have gained considerable attention for sensing and recognition of ions and molecules. Copper (Cu2+) is an essential element required in trace amounts in all living organisms to carry out various biological processes. The aim of this review is to summarize advancement in π-conjugated fluorogenic and chromogenic groups appended to calix[4]arene motifs for detection and quantitation of Cu2+ ion. The focus is to present a comprehensive account of extended calix[4]arene systems with different linkers and highlight the unique design and binding characteristics for the recognition and sensing of Cu2+ ions.

A New Conformationally Symmetrical Calix[4]pyrrole Based Supramolecular System for Liquid Crystalline and Window Layer Solar Cell Applications.

The newly symmetrical liquid crystalline compounds (CPB1 -CPB4 ) based on calix[4]pyrrole as central rigid core are synthesized via esterification reaction. All the four functionalized compounds exhibit columnar hexagonal phase (Colh ) over a higher mesophase temperature range and further stabilized mesophase upto room temperature. The thermal behavior and optical texture are identified by using differential scanning calorimetry (DSC), Polarizing optical microscopy (POM) while the molecular organization of compound in mesogenic state by X-ray diffraction technique. The molecular system based on calix[4]pyrrole core with symmetrical nature exhibited columnar type self-assembly at room temperature. All these four supramolecules with different side spacer show higher thermal stability. Based upon the optimization, compound CPB2 has been further tested to implicate as optical window layer in thin films solar cell devices. The calix[4]pyrrole functionalized supramolecular liquid crystalline compound based thin films showed suitable transmittance, optical energy band gap together with absorbance and extinction coefficient. The linear dependence of current on the voltage demonstrated Ohmic behavior of the CPB2 films. The surface morphology to the developed samples designated nearly uniform deposition of the CPB2 thin films together with grain growth. The findings warrant suitability of the films to implicate these as an eco-friendly optical window layer in thin films based solar cells.

Fucoidan, a brown seaweed polysaccharide in nanodrug delivery.

Fucoidan-a sulfated marine seaweed obtained from brown algae-has raised considerable interest in the scientific community over the last decade as it possesses a wide range of biological activities such as antioxidant, antiviral, anti-inflammatory, anticoagulant, antithrombotic, anticarcinogenic, and immunoregulatory. This polysaccharide finds application as a drug delivery vehicle due to its non-cytotoxicity, biocompatibility, and biodegradability. Besides, nano biomedical systems have used this marine alga for diagnostic and therapeutic purposes. Fucoidan has been extensively studied for use in regenerative medicines, in wound healing, and for sustained drug delivery due to its large biodiversity, cost-effectiveness, and mild procedures for extraction and purification. However, the main concern that limits its application is the variance in its batch-to-batch extraction owing to species type, harvesting, and climatic factors. The current review encloses a compendious overview of the origin, chemical structure, and physicochemical and biological properties of fucoidan and its significant role in nanodrug delivery systems. Special emphasis is given to the recent advances in the use of native/modified fucoidan, its combination with chitosan and metal ions for nanodrug delivery applications, especially in cancer treatment. Additionally, use of fucoidan in human clinical trials as a complementary therapeutic agent is also reviewed.

Bioprospecting phytochemicals of Rosmarinus officinalis L. for targeting SARS-CoV-2 main protease (Mpro): a computational study.

CONTEXT: The persistent spread of highly contagious COVID-19 disease is one of the deadliest occurrences in the history of mankind. Despite the distribution of numerous efficacious vaccines and their extensive usage, the perpetual effectiveness of immunization is being catechized. Therefore, discovering an alternative therapy to control and prevent COVID-19 infections has become a top priority. The main protease (Mpro) plays a key role in viral replication, making it an intriguing pharmacological target for SARS-CoV-2. METHODS: In this context, virtual screening of thirteen bioactive polyphenols and terpenoids of Rosmarinus officinalis L. was performed using several computational modules including molecular docking, ADMET, drug-likeness characteristics, and molecular dynamic simulation to predict the potential inhibitors against SARS-CoV-2 Mpro (PDB: 6LU7). The results suggest that apigenin, betulinic acid, luteolin, carnosol, and rosmarinic acid may emerge as potential inhibitors of SARS-CoV-2 with acceptable drug-likeness, pharmacokinetics, ADMET characteristics, and binding interactions comparable with remdesivir and favipiravir. These findings imply that some of the active components of Rosmarinus officinalis L. can serve as an effective antiviral source for the development of therapeutics for SARS-CoV-2 infection.

Thiacalixarene Appended Azo-based Supramolecular Systems: Self-assembly and Photo Tuning Reversible Liquid Crystalline Properties.

Four new azo-based supramolecular materials containing thiacalixarene core substituted by variable alkoxy groups (TFA1 -TFA4 ) have been designed and synthesized for the mesomorphic and photoswitching properties. The liquid crystalline behavior were accomplished by using DSC, POM, and XRD studies. All azo-based thiacalixarene based materials with short and higher chain length display columnar hexagonal mesophase with broad temperature range. The thermal behavior of all the materials was investigated by DSC and TGA study. The structural and conformational study of the lower rim functionalized materials was confirmed by using different techniques. These thiacalixarene moulded liquid crystalline compounds shows columnar self-assembly type behavior and higher thermal stability. The introduction of bi-substituted azo-ester network towards the lower rim of thiacalixarene core has impact on the electron delocalization and liquid crystalline properties. The photoswitching properties suggested cis and trans azo-isomerization under radiation of UV light and higher thermal back relaxation time. The mesogenic behaviour of compound TFA2 and TFA4 were demolished by the influence of cis and trans isomerization. The structure-property correlation is studied to understand the variation in mesogenic properties with the substitution of variable alkoxy side chain.

Preparation and optimization of tetraethyl orthosilicate cross-linked chitosan-guar gum-poly(vinyl alcohol) composites reinforced with montmorillonite for sustained release of sitagliptin.

Development of efficient drug carriers has become an integral part of advanced drug delivery systems. This work aims at developing composites by adopting an economically viable method for sustained release of anti-diabetic drug sitagliptin - a potent and selective dipeptidyl peptidase-IV inhibitor. To combat the harsh environment of gastrointestinal tract, the composite (F13) was prepared using biodegradable polymers namely chitosan, guar gum and poly(vinyl alcohol) with montmorillonite clay as nano-filler and tetraethyl orthosilicate as the cross linker. The composites were characterized using FT-IR, XRD, DSC and SEM techniques. Physical properties such as thickness, swelling capacity, folding endurance and water solubility were studied. In vitro analysis of composites (F17, F19 and F20) in simulated gastric medium showed <14 % cumulative release in 2 h while a sustained release was observed in simulated intestinal medium. Drug release kinetics was investigated using five mathematical models namely zero order, first order, Higuchi, Hixon-Crowell and Korsemeyer-Peppas wherein the latter was the best fit model (R2, 0.969). Antimicrobial studies of drug free composite (F13) revealed good activity against bacteria as well as fungi. The results implied that the composites were pH sensitive and could serve as a potential choice for sustained release of drugs.

Calixarene Functionalized Supramolecular Liquid Crystals and Their Diverse Applications.

Liquid crystals are considered to be the fourth state of matter with an intermediate order and fluidity in comparison to solids and liquids. Calixarenes are among one of the most versatile families of building blocks for supramolecular chemistry due to their unique vaselike structure that can be chemically engineered to have different shapes and sizes. During the last few decades, calixarenes have drawn much attention in the field of supramolecular chemistry due to their diverse applications in the fields of ion and molecular recognition, ion-selective electrodes for catalysis, drug delivery, gelation, organic electronics and sensors, etc. Imbuing liquid crystallinity to the calixarene framework leads to functionalized calixarene derivatives with fluidity and order. Columnar self-assembly of such derivatives in particular enhance the charge migration along the column due to the 1D stacking due to the enhanced π-π overlap. Considering limited reports and reviews on this new class of calixarene based liquid crystals, a comprehensive account of the synthesis of calixarene liquid crystals along with their mesomorphic behavior and potential applications are presented in this review.

A Status Update on the Development of Polymer and Metal-Based Graphene Electrochemical Sensors for Detection and Quantitation of Bisphenol A.

The detection and quantitation of bisphenol A (BPA) in the environment and food products has been a subject of considerable interest. BPA, a diphenylmethane derivative is a well-known industrial raw material with wide range of applications. It is a well-known endocrine disruptor and acts as an estrogen mimic. BPA is an environmental health concern and its accumulation in hydro-geological cycles is a matter of serious ecological peril. This review basically assesses various chemically modified electrodes composed of diverse components that have been employed to recognize BPA in different matrices. Electrochemical sensors prepared using graphene materials in combination with metals and polymers for selective detection of BPA have been discussed extensively. The emphasis is on detection of BPA in various samples encountered in routine use such as plastic bottles, receipts, baby feed bottles, milk samples, mineralized water, tissue paper, DVDs, and others. Although research in this field is in the exploratory stage, deeper insights into fundamental studies of sensing systems, fast analysis of real samples and validation of sensors are some of the factors that need major impetus. It is expected that chemically modified electrode-based sensing systems will soon take over as a viable option for monitoring diverse pollutants.

Hybrid solid-phase extraction to overcome interference due to phospholipids for determination of neratinib in human plasma using UPLC-MS/MS.

A reliable and robust bioanalytical method was developed to quantify neratinib, a tyrosine kinase inhibitor in human plasma, using UPLC-MS/MS. The extraction of neratinib and its deuterated internal standard, neratinib-d6, was successfully performed on hybrid solid-phase extraction ultra-cartridges to remove the interference of phospholipids and proteins. Chromatographic analysis was performed on a UPLC BEH C18 (50 × 2.1 mm, 1.7 µm) column using 0.1% formic acid and acetonitrile under gradient conditions. The total analysis time was 1.5 min. Neratinib was quantified using electrospray ionization source operated in the positive-ion multiple reaction monitoring mode. The mass transitions of neratinib and neratinib-d6 were m/z 557.3/112.1 and m/z 563.1/118.2, respectively. The linear concentration range for neratinib was 0.5-500 ng/mL, which adequately covers concentration levels expected in real subject samples. The assay was extensively validated for various validation parameters following standard guidelines for a bioanalytical assay. The intra- and inter-batch precision was ≤4.6%, and neratinib was found to be stable under various stability conditions. The mean internal standard-normalized matrix factor and recovery were 0.997 and 95.4%, respectively. The validated method was successfully applied to a pharmacokinetic study in healthy subjects with different doses.

Photodynamic therapy with light emitting fabrics: a review.

Photodynamic therapy is a powerful tool in the localized and selective treatment of dermatologic diseases, such as actinic keratosis, acne vulgaris, Bowen's disease and basal cell carcinoma. The success of photodynamic therapy is mainly attributed to the development of flexible light sources for homogenous and reproducible illumination during clinical studies. The essential requirement for this therapy includes, a suitable photosensitizer, presence of oxygen and a light of specific wavelength and intensity. The use of light emitting fabric comprising of optical fibers provides an exciting and an efficient way to transfer light directly to the skin uniformly on the infected body parts. As the optical fibers can transmit light from 400 to 1200 nm it is possible to combine light emitting fabric with laser sources for medical applications. This review focusses on the challenges and recent developments in the use of light emitting fabric for photodynamic therapy in clinical studies and its future perspectives.

Simultaneous enantioseparation and simulation studies of atenolol, metoprolol and propranolol on Chiralpak® IG column using supercritical fluid chromatography.

Enantioseparation of three ß-blockers, i.e., atenolol, metoprolol and propranolol, was studied on amylose tris(3-chloro-5-methylphenylcarbamate) immobilized chiral stationary phase using supercritical fluid chromatography (SFC). The effect of organic modifiers (methanol, isopropanol and their mixture), column temperature and back pressure on chiral separation of ß-blockers was evaluated. Optimum chromatographic separation with respect to resolution, retention, and analysis time was achieved using a mixture of CO2 and 0.1% isopropyl amine in isopropanol: methanol (50:50, V/V), in 75:25 (V/V) ratio. Under the optimized conditions, the resolution factors (R s) and separation factors (α) were greater than 3.0 and 1.5, respectively. Further, with increase in temperature (25-45 °C) and pressure (100-150 bars) there was corresponding decrease in retention factors (k), α and R s. However, a reverse trend (α and R s) was observed for atenolol with increase in temperature. The thermodynamic data from van't Hoff plots revealed that the enantioseparation was enthalpy driven for metoprolol and propranolol while entropy driven for atenolol. To understand the mechanism of chiral recognition and the elution behavior of the enantiomers, molecular docking studies were performed. The binding energies obtained from simulation studies were in good agreement with the elution order found experimentally and also with the free energy values. The method was validated in the concentration range of 0.5-10 µg/mL for all the enantiomers. The limit of detection and limit of quantitation ranged from 0.126 to 0.137 µg/mL and 0.376-0.414 µg/mL, respectively. The method was used successfully to analyze these drugs in pharmaceutical preparations.

Application of supercritical fluid chromatography for separation and quantitation of 15 co-formulated binary anti-hypertensive medications using a single elution protocol.

A facile supercritical fluid chromatography method is proposed to analyse 15 co-formulated binary anti-hypertensive drug combinations using a customized elution procedure. The effect of mobile phase composition, column back pressure and temperature was suitably optimized for adequate retention, analyte response and resolution. The chromatographic separation of the different drug combinations was performed on a DCPak poly(4-vinylpyridine) column (250 × 4.6 mm, 5 µm) at 125-bar pressure and 40°C using a photodiode array detector. A linear gradient of CO2 and 0.1% formic acid in methanol provided the best elution conditions for all drug combinations. Baseline separation of the drugs was possible with resolution factor Rs ranging from 1.42 to 12.58. The method was validated for specificity, sensitivity, accuracy and precision, recovery and robustness. The limit of detection and limit of quantitation for aliskiren, amlodipine, atenolol, candesartan, hydrochlorothiazide, lisinopril, losartan, metoprolol, olmesartan, telmisartan and valsartan were in the range of 0.26-2.56 and 0.77-7.75 µg/mL, respectively. The thermodynamic study revealed that interactions of the drugs with the stationary phase were spontaneous as evident from the negative free energy values, and the separation process was enthalpy driven. The developed method was successfully employed to analyse these drugs in their co-formulated tablet formulations.

Analytical separation of four stereoisomers of luliconazole using supercritical fluid chromatography: Thermodynamic aspects and simulation study with chiral stationary phase.

The work describes a novel supercritical fluid chromatography method for the separation of four stereoisomers, RZ(+), SZ(-), RE(+) and SE(-) of luliconazole, an antifungal agent on amylose tris[(S)-α-methylbenzyl carbamate] based Chiralpak IH column. The effect of organic modifiers (methanol, ethanol and isopropanol), column temperature and back pressure were evaluated for their selective separation. A consistent elution order, RZ(+) > SZ(-) > RE(+) > SE(-) was observed in all the modifiers. Amongst the three modifiers, the best result in terms of selectivity, resolution and analysis time was obtained with isopropanol. Analytical separation (Rs > 1.5) of RZ(+) and SZ(-) & RE(+) and SE(-) pairs was achieved with a mobile phase consisting of CO2: isopropanol (80: 20, v/v) within 5.0 min. The retention of isomers increased with increase in temperature and decreased with increase in pressure, which was more prominent for RE(+) and SE(-) isomers. The van't Hoff plots revealed that the chiral separation process was essentially entropy driven. Molecular docking was performed to understand the type of chiral recognition between the stereoisomers and the chiral stationary phase and to understand their elution orders under optimized conditions. The results suggested hydrogen bonding and π-π interactions, as the dominant interaction modes. The elution order and binding energy of the interactions were in good agreement with the experimental results. Quantitative studies of RE(+) luliconazole the pharmacologically active isomer was also performed using a marketed formulation.

Separation of achiral anti-diabetic drugs using sub/supercritical fluid chromatography with a polysaccharide stationary phase: Thermodynamic considerations and molecular docking study.

A simple, fast and environmental friendly supercritical fluid chromatography-photodiode array (SFC-PDA) method was developed for the simultaneous determination of metformin and three sodium-glucose co-transporter 2 (SGLT-2) inhibitors (canagliflozin, dapagliflozin and empagliflozin). The impact of different stationary phases, co-solvents, column temperature and outlet pressure was extensively evaluated for selective separation and quantitation of the drugs. Amongst several achiral and chiral stationary phases tested, the best results were obtained on amylose based Chiralpak IG column using CO2 and 0.1 % diethylamine in methanol and isopropanol 50:50 (v/v) in 60:40 ratios as the mobile phase. The separation efficiency was mainly dependent on the nature of stationary phase and the mobile phase composition. The limit of detection (LOD) and quantitation (LOQ) of the method were 0.155 and 0.469, 0.062 and 0.187, 0.015 and 0.045, 0.028 and 0.084 µg/mL for metformin, canagliflozin, dapagliflozin and empagliflozin, respectively. The chromatographic resolution between metformin-canagliflozin, metformin-dapagliflozin and metformin-empagliflozin pairs was 6.87, 3.44 and 6.47, respectively. The intra-batch and inter-batch precision of the method was ≤1.64 % while the accuracy was in the range of 96.2-103.3 %. The method was used to analyze metformin and SGLT-2 inhibitors in their binary fixed-dose formulations with acceptable accuracy (recovery) and precision. To support the experimental results, molecular docking was performed on Schrodinger software to provide a deeper insight into the interactions between the analytes and the chiral stationary phase and to understand their elution orders under optimized conditions.

Modulation of inner filter effect of non-conjugated silver nanoparticles on blue emitting ZnS quantum dots for the quantitation of betahistine.

A simple, reliable and efficient fluorescent probe has been developed for the detection and quantitation of betahistine using inner filter effect (IFE) of silver nanoparticles (AgNPs) on zinc sulphide (ZnS) quantum dots. The synthesized ZnS exhibited blue emission at 403 nm which was quenched upon mixing with AgNPs due to intensive localized surface plasmon resonance (LSPR) absorption at 401 nm. The presence of IFE was confirmed by UV-Visible and fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. Addition of betahistine caused aggregation of AgNPs as visualized by the change in colour of nano-suspension. The reduced absorption at LSPR resulted in inhibition of IFE leading to higher fluorescence intensities in the presence of betahistine. Parameters such as pH, incubation time and concentration of AgNPs were suitably optimized. The fluorescence signal (I - I0/I0) responded linearly for betahistine in the concentration range from 0.1 to 10 µM under the optimized experimental conditions. Due to the aggregation of AgNPs, a simple colorimetric approach was also studied for quantitation of betahistine in the range 1.0-20 µM. The limit of detection for fluorescence measurement and colorimetric approach was 0.02 µM and 0.23 µM, respectively. Further, the proposed method exhibited excellent selectivity towards betahistine in presence of several cations, biomolecules such as glucose, uric acid, creatinine, amino acids and several anti-vertigo medications. The method was applied to quantify betahistine from pharmaceutical products and results obtained were in good agreement with the claimed values. The proposed sensor can serve a low cost, selective, sensitive and a precise tool for routine quantitation of betahistine.