Aqueous Research Articles

Ultrasound-Assisted Catalyst-free Synthesis of α,β -Unsaturated Amino Acid Esters and Unsaturated Amino Ketones

Introduction: Sonication has been introduced as a green and effective activation method for the selective monoamination of β-dicarbonyl compounds. The simple one-pot process resulted in different substituted β-amino-ɑ,β-unsaturated esters and ketones at room temperature with quantitative yields. Aqueous NH4OH was used as a safe and economical nitrogen source for pressurized NH3 gas. The process is considered green, accounting for not using any solvents and catalysts, besides some aqueous NH4OH-involved reactions using nontoxic water. A broad variety of useful synthetic intermediates, β- amino-ɑ,β-unsaturated esters and ketones have been prepared in short reaction time. Methods: Using this developed protocol, we were able to synthesize a series of structurally diverse β- amino-ɑ,β-unsaturated esters and unsaturated amino ketones. Results: The synthesis of target compounds was achieved in a truly green process with high atom economy and excellent yields in a catalyst-free one-pot system in an aqueous medium using simple, commercially available, inexpensive ammonium hydroxide as the source of the nitrogen. The high atom economy has been accompanied by the formation of a small amount of nontoxic waste, water. Conclusion: In conclusion, a simple, convenient, and high-yielding catalyst-free environmentally benign method was developed for the synthesis of unsaturated amino acid esters and unsaturated amino ketones.

Removal of cadmium and chromium heavy metals from aqueous medium using composite bacterial cellulose membrane

Bacterial cellulose (BC) membranes produced from biomass are emerging as an eco-friendly solution for water decontamination. The abundance of hydroxyl groups and the high surface-to-volume ratio of this material allow for the integration of diverse functional groups, providing the potential for targeted water purification applications. Beyond their intriguing mechanical properties and unique complex structure, bacterial cellulose membranes are biodegradable into sugar molecules and can be processed with minimal handling and using mild chemicals. Taken together, these features make them a compelling choice for water filtration in the context of environmental responsibility. In their natural state, BC membranes have limited potential for targeted wastewater treatment. One strategy for enhancing their functionality is to graft customized molecules onto their surface. Therefore, this study aims to impart multifunctionality to BC membrane for water filtration. Hence a novel precursor with hard and soft base functionalities consisting of amines, carbonyls, amides, hydroxyls etc. is designed and grafted onto BC membranes, grown to ensure surface uniformity and membrane-to-membrane repeatability of the properties. The structure of the synthesized precursors and the effective functionalization of the membrane are then validated through various structural characterization techniques. Changes in the morphology of BC membranes are examined using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Both the pristine and modified BC membranes undergo a series of tests to assess their filtration capabilities under low-pressure regime and their efficiency in removing representative cadmium and chromium ions. The modified BC membrane exhibits superior filtration performance and water permeability than pristine-BC. The targeted metal ions were rejected more than 90% from the effluent. The modified membranes demonstrated a flux recovery of above 90% maintaining its effectiveness even after five successive cleaning-filtration cycles.

Study on pH dependent ON/OFF fluorescent switching behaviour of hydrothermally synthesised vanadium disulphide quantum dots (VS2-QDs)

It is fascinating to design and develop an inorganic quantum dot (QDs) which exhibit luminescence features with ion concentration, temperature, and pH sensitivity dependence. Vanadium disulphide (VS2) belongs to the family of transition metal dichalcogenides (TMDs), and is extensively studied owing to its layered characteristics features in sensing and filtrations technology, however, its fluorescence features have not been well studied so far. The current work describes a widely adopted eco-friendly hydrothermal approach for the synthesis of VS2-QDs. The average size of particles was determined to be ∼10 nm by transmission electron microscopy (TEM) and Zetasizer analysis. The synthetic approach adopted here facilitates in situ functionalization of QDs, which results in their high stability in aqueous medium and enhanced sensitivity towards their surroundings. As most of the QDs show the sensitivity towards pH, a thorough investigation of VS2 QDs for their pH dependent photoluminescence has been carried out. The VS2-QDs were discovered to exhibit a remarkable luminescence intensity that was found to be about 11 times higher in basic conditions (pH ∼ 13, QY = ∼4.80%) as compared to that in acidic conditions (pH ∼ 1, QY = ∼1.10%). The root cause of this ON/OFF florescence flipping may be related to the functional groups (such as −SO42−, −NH2, OH−, etc.) attached over the surface of QDs, acid etching, and protonation–deprotonation process. This paper highlights the pH dependent switching behaviour of VS2-QDs that could offer valuable information for designing a futuristic pH-based device for biomedical applications.

An Efficient Propylphosphonic Anhydride (T3P®)-Mediated MW-induced Solvent-free Rapid Synthesis of Enamino Esters and Ketones including 5, 5-Dimethyl-3-aminocyclohex-2-enones

Abstract: This work presents a clean and convenient synthesis of various β-enaminones including 5,5- dimethyl-3-aminocyclohex-2-enones, in satisfactory to excellent yields from the condensation reaction of primary amines with β -dicarbonyls by employing T3P® as a catalyst and performing the reaction under microwave irradiation and solvent-free conditions. These rapid reactions launched readily and stood a diversity of organic functional groups. A mixture of 1,3-dicarbonyl compound, primary amine and T3P® (50% in AcOEt) was irradiated for an appropriate time under microwave at 80°C. After completing the reaction (TLC) and cooling to r.t., ethyl acetate and saturated aqueous NaHCO3 solution were added. The aqueous phase was extracted ethyl acetate. The combined organic layer was washed with brine, dried over Na2SO4, and filtered, and the solvent was removed under reduced pressure to afford the product, which was recrystallized from diisopropyl ether. The presented results exhibit a better catalytic activity of T3P in the synthesis of enaminones. It could be concluded that T3P is the best catalyst as it took only a few minutes for the completion of the reaction with an excellent yield of product, which indicates T3P is more efficient, compared to other catalysts. A comparison of the efficiency of the present procedure with some heterogeneous solid catalysts was evaluated as well. Clearly, a higher yield was established in this procedure compared to other catalysts. Furthermore, the reaction of amines with dimedone was investigated as well, delivering excellent yields. The reaction catalyzed by T3P under microwave irradiation supplies a comprehensive method for the synthesis of enaminones. In this work, T3P is an effective, efficient and green catalyst, which forms the procedure economic, suitable, and safe with widespread application in the synthesis of enaminones. background: This work presents a clean and convenient synthesis of various β-enaminones incuding 5,5-dimethyl-3-aminocyclohex-2-enones in good to excellent yields from the reaction of different primary amines with 1,3-dicarbonyl compounds by employing T3P® as a catalyst and performing the reaction under microwave irradiation and solvent-free conditions. This one-pot rapid reaction proceeded readily and tolerated a variety of functional groups.

Sulfide mediated zero valent iron for enhanced nickel removal under neutral condition: reaction kinetic, mechanism, and stability

The application of sodium sulfide (Na2S) as sulfidation reagent of zero valent iron (ZVI) has been well studied, however, the effect of Na2S existence on ZVI reactivity remains obscure. In this study, Ni(II) removal performance, mechanism, and stability by ZVI with Na2S were investigated at neutral condition. The results showed that Ni(II) removal sharply increased from < 5% to 100% by ZVI within 60min with the increase of Na2S concentration, but the subsequent Ni(II) release occurred. In addition to the slight Ni(II) removal by Na2S in aqueous phase, Ni(II) was mainly removed by the adsorption and reduction by Na2S mediated ZVI system. Characterization analysis indicated that Na2S could lead to the severe Fe0 corrosion and the main corrosion product on ZVI was lepidocrocite, which played the dominant role for Ni(II) immobilization. Meanwhile, the formation of iron sulfides on ZVI surface would enhance Ni(II) reduction and partially transform the adsorbed Ni(II) to NiS. Moreover, the higher ionic strength could further enhance the initial Ni(II) removal rate but the stability became poor. Regardless of the additive methods, the Ni(II) removal significantly enhanced in the system of ZVI and Na2S combination. Overall, this work reveals the sulfide mediated Fe0 corrosion and provides a potential method for enhancing the reactivity of ZVI in the treatment of Ni(II) pollution.

Edible superhydrophobic coating derived from triterpenoid maslinic acid for bacterial antifouling and enhanced fresh produce food safety

This study introduces an edible superhydrophobic coating for fresh produce derived from triterpenoid maslinic acid (MA), a natural plant compound renowned for its health benefits including antioxidant, antitumor, and anti-inflammatory properties. The study takes advantage of the amphiphilic nature of MA, forming vesicles in aqueous media. Upon deposition onto the substrate, these vesicles contribute to surface roughness, resulting in a nanotextured morphology with nonpolar outer surface. Static water contact angle of MA coatings was 151.6 ± 0.8°, indicating superhydrophobic behavior exhibiting promising bacterial antifouling characteristics with 98.6%, 96.7% and 97.5% reduction against E. coli, Salmonella and Listeria, respectively, compared to uncoated surfaces (i.e., onion skin). The development of edible, superhydrophobic coatings for application on fresh produce advances current fruit and vegetable wax technologies, mostly used for cosmetic and physical barrier purposes rather than more functional ones. Using assembled MA coatings combining superhydrophobicity and health benefits, emerges as an novel and sustainable solution for advancing both fresh produce safety and human well-being.

A water-soluble preparation for intravenous administration of isorhamnetin and its pharmacokinetics in rats

Flavonoids are considered as health-protecting food constituents. The testing of their biological effects is however hampered by their low absorption and complex metabolism. In order to investigate the direct effect(s) of unmetabolized flavonoid, a preparation in a biologically friendly solvent for intravenous administration is needed. Isorhamnetin, a natural flavonoid and a human metabolite of the most frequently tested flavonoid quercetin, has very low water solubility (< 3.5 μg/mL). The aim of this study was to improve its solubility to enable intravenous administration and to test its pharmacokinetics in an animal model. By using polyvinylpyrrolidone (PVP10) and benzalkonium chloride, we were able to improve the solubility approximately 600 times to 2.1 mg/mL. This solution was then administered intravenously at a dose of 0.5 mg/kg of isorhamnetin to rats and its pharmacokinetics was analyzed. Pharmacokinetics of isorhamnetin corresponded to two compartmental model with a rapid initial distribution phase (t1/2α: 5.7 ± 4.3 min) and a slower elimination phase (t1/2β: 61 ± 47.5 min). Two sulfate metabolites were also identified. PVP10 and benzalkonium did not modify the properties of isorhamnetin (iron chelation and reduction, and cell penetration) substantially. In conclusion, the novel preparation reported in this study is suitable for future testing of isorhamnetin effects under in vivo conditions.

Flavonoid-metal ion Complexes as Potent Anticancer metallodrugs: A comprehensive Review.

Flavonoids and their analogous are mainly found in pink lady apples, green and black tea (catechins), celery and red peppers, onions, broccoli and spinach, berries, cherries, soybean, citrus fruits, and fungi. The different derivatives of flavonoids belonging to polyphenolic compounds such as 3,4',5,7-Tetrahydroxyflavylium (pelargonidin), 2-(3,4-Dihydroxyphenyl)chromenylium-3,5,7-triol (cyanidin), 3,3',4',5,5',7-Hexahydroxyflavylium (delphinidin), 3,3',4',5,7-Pentahydroxy-5'-methoxyflavylium (petunidin), and 3,4',5,7-Tetrahydroxy-3',5'-dimethoxyflavylium (malvidin) can act as good chelating agents for metal-chelate complex formation. These flavonoid-metal complexes have been reported to have various biomedical and pharmacological activities. Flavonoid-metal ion complexes display a broad spectrum of biological properties such as antioxidant, anti-inflammatory, anti-allergic, antiviral, anticarcinogenic, and cytotoxic activity. The literature survey showed that flavonoid metal complexes have potential therapeutic properties against various cancerous cells. The objective is to gain insight into the current perspective and development of novel anticancer metallodrug drugs. The flavonoid-metal ion complexes can be prepared by reacting flavonoid ligand with appropriate metal salt in aqueous or alcoholic reaction medium under stirring or refluxing conditions. In this review article, the various reported methods for the synthesis of flavonoid-metal complexes have been included. The utility of synthetic methods for flavonoid-metal complexes will support the discovery of novel therapeutic drugs. In this review study, short libraries of flavonoid-metal ion complexes were studied as potential anticancer agents against various human cancer cell lines. The review report reveals that metal ions such as Fe, Co, Ni, Cu, Zn, Rh, Ru, Ga, Ba, Sn etc., when binding to flavonoid ligands, enhance the anticancer activity compared to free ligands. This review study covered some important literature surveys for the last two decades. It has been concluded that flavonoid metal complexes have been associated with a wide range of biological properties that could be noteworthy in the medicinal field. Therefore, to develop a new anticancer drug, it is essential to determine the primordial interaction drug with DNA under physiological or anatomical conditions. The study of numerous flavonoid metal complexes mentioned in this paper could be the future treatment against various cancerous diseases.

Hydrophilic Interaction Liquid Chromatography for the Analysis of Pharmaceutical Formulations

Abstract: For a long time, Reversed-Phase Liquid Chromatography (RPLC) was the most dominant technique for the analysis of pharmaceutical compounds, but with poor efficiency in the separation of small polar molecules. From the efforts to solve the problem of insufficient retention of these molecules, during the last decades, a mode of liquid chromatography named Hydrophilic Interaction Liquid Chromatography (HILIC) has experienced vast expansion. It is based on the use of a highly hydrophilic stationary phase along with an aqueous mobile phase with high organic modifier content. In this review, the characteristics of stationary and mobile phases used in HILIC are described, and corresponding separation mechanisms are discussed. An overview of recently published papers dealing with the application of HILIC in analyzing pharmaceuticals in biological and non-biological samples is provided. Besides, the application of HILIC systems in the determination of the physicochemical properties of compounds is described.

A digital bar pH indicator based on a microfluidic paper-based analytical device

A pH value of an aqueous medium is an essential parameter in the environment and biology. Nowadays, it is possible to measure using a colorimetric pH paper or an electrochemical pH meter. However, since the two methods have drawbacks of the limited precision in pH determination and the careful management of a glass membrane electrode, respectively, it still remains as a challenge to discover a user-friendly, reliable pH-measuring device. Herein, a novel digital bar pH indicator was developed using a microfluidic paper-based analytical device (μPAD) to determine with the naked eye the pH value of an aqueous sample. The fabricated digital indicator consists of seven independent pH sensors displaying a color change from yellow to greenish blue above specific pH values. These sensing elements were vertically aligned to form a bar shape, and their color-changing pH points were regulated to increase upward from 4.5 to 7.5 with an interval of 0.5 units. For fast and simultaneous detection of the colorimetric sensors, sample addition to an inlet of the μPAD was quickly transported vertically along a hollow paper channel, horizontally divided, and arrived at the detection zones at similar times via delay channels. Through independent experiments, control of the color-changing pH point and flow rate were confirmed by addition of a surfactant additive into the pH indicator and inserting empty spaces in a flow channel, respectively. Reliable operation of the fabricated μPAD was verified using standard pH buffer samples. Finally, the feasibility of our digital bar pH indicator was successfully demonstrated for determining the pH value of a urine sample under the resolution of 0.5 units.

Enantioselective liquid-liquid extraction of 2-cyclohexylmandelic acid enantiomers using chiral ionic liquids.

Obtaining optically pure compounds in an eco-friendly and cost-efficient manner plays an important role in human health and pharmaceutical industry. Racemic separation using multistage stereoselective liquid-liquid extraction has become one of the most practical and effective approach to access homochiral enantiomers. Currently, chiral ionic liquids (CILs) with structural designability have become a promising chiral additive and enable them as adjustable candidates for racemic separation. Herein, a high-effective stereoselective liquid-liquid extraction process composed of imidazolium cations and amino acid-derived anions as the chiral additive was established for racemic 2-cyclohexylmandelic acid (CHMA) separation. We have systematically investigated the choice of organic solvent, concentration of CIL, extraction temperature, and the pH of aqueous phase. For three-stage stereoselective extraction, the maximum enantiomeric excess (e.e.) for CHMA was reached up to 40.6%. Furthermore, the mechanism of steric effect and stereoselective capacity between the CILs and racemic CHMA was discussed and simulated. We envision that the work will facilitate the development of CILs in multistage liquid-liquid extraction and promote the large-scale production of optically pure enantiomers.

Polyvinyl alcohol-based multifunctional hydrogel film: a novel strategy for food preservation packaging

Food spoilage leads to the annual huge wastage of food. There is a pressing need for safe, multifunctional food preservation packaging to curb this wastage and prevent contamination. In this study, we present a novel, cross-linked P-GL hydrogel film with a smooth surface microstructure, derived from polyvinyl alcohol (PVA), gallic acid (GA), and lysozyme (L). This hydrogel film serves as an exceptional packaging material for food preservation, displaying an ability to completely block UV light and efficiently impede the penetration of water vapor and O2. Remarkably, the P-GL hydrogel film exhibits a fracture strength of approximately 37.9 MPa, demonstrating superior water solubility, thermal stability, and mechanical properties. Also, this P-GL hydrogel film can effectively eliminate E. coli and S. aureus. The P-GL hydrogel film has proven to be successful in mitigating the spoilage of blueberries through coating and covering treatments, outperforming commercial plastic wrap. As a result, the shelf life of blueberries can be extended to 20 days. Our work provides innovative insights that could potentially drive the use of safe and multifunctional hydrogel films in the food preservation packaging industry.

Curcumin-Enclosed Nanoparticles for Cancer Therapy

Abstract: Cancer is the greatest cause of mortality worldwide, and it is distinguished by the unrestrained proliferation of a group of aberrant cells, the random division of cells, and the invasiveness of genetically organized cells. At present, there are various strategies for curing of cancer-based on the type &amp; severity. In the earlier two decades, curcumin has received huge attention in pharmacological, biological, and nutraceutical research. In addition to triggering apoptosis in cancer cells, curcumin also inhibits cancer cell invasion and proliferation by stifling cellular signaling pathways. The lower water solubility of curcumin decreases the oral bioavailability, absorption into the systemic circulation, and chemical stability and finally bound the activity of curcumin as an anticancer agent. The pharmacology of curcumin, as well as its derivatives with relation to its anticancer potential, primary modes of action, &amp; cellular target, has been summarised in this article along with a list of the numerous curcumin enclosing nanoformulations. Multiple methods of administration have been developed for curcumin to boost its specificity. Encapsulation and other formulation processing techniques have been found to enhance both the solubility and bioavailability of curcumin. The nanoparticles' size, shape, surface characteristics, and targeting ligand are all factors that nanoformulation designers must think about when working to increase the efficacy and cellular targeting of anticancer treatments.

Review on Paclitaxel Derivatization: Enhanced Anticancer Action

Background: The United States Food and Drug Administration (FDA) has authorized paclitaxel for the treatment of numerous types of cancer, including breast, lung, ovarian, and Kaposi's sarcoma. It possesses all the characteristics of BCS class IV medications, including low bioavailability, low water solubility, poor permeability, unpredictable and poor absorption, and inter- and intrasubject variability. Objective: The purpose of this research was to evaluate previous efforts done to derivatize paclitaxel for greater effectiveness. Methods: A systematic literature review was conducted from a variety of sources, including published research, review articles, and patents, that mainly focus on the derivatization of paclitaxel that has been done in the last 10 years to enhance its solubility, permeability, and bioavailability. Different forms of derivatization were done in order to improve the drug's ability to be absorbed by the body, as well as its solubility and bioavailability. Results: This article explores the current and future strategies for increasing the anti-cancer efficacy of paclitaxel by enhancing its bioavailability, solubility, and penetration efficacy. Some examples are lipidbased delivery systems, polymer-based nanocarriers, crystal engineering (nanocrystals and co-crystals), liquidsolid technologies, and self-emulsifying solid dispersions. Other strategies are also discussed in this article. Conclusion: It is quite likely that this review article will contain perfect fragments of evidence for building a new model for the application of paclitaxel in the treatment of cancer.

Effect of surfactant's charge properties on behavior, physiology, and biochemistry and the release of microcystins of Microcystis aeruginosa

Surfactant pollution is escalatitheng in eutrophic waters, but the effect of surfactant charge properties on the physiological and biochemical properties of toxin-producing microalgae remains inadequately explored. To address this gap, this study explores the effects and mechanisms of three common surfactants―cetyltrimethylammonium bromide (CTAB, cationic), sodium dodecyl sulfate (SDS, anionic), and Triton X-100 (nonionic)―found in surface waters, on the agglomeration behavior, physiological indicators, and Microcystin-LR (MC-LR) release of Microcystis aeruginosa (M. aeruginosa) by using UV-visible spectroscope, Malvern Zetasizer, fluorescence spectrometer, etc. Results suggest that charge properties significantly affect cyanobacterial aggregation and cellular metabolism. The CTAB-treated group demonstrates a ∼5.74 and ∼9.74 times higher aggregation effect compared to Triton X-100 and SDS (300 mg/L for 180 min) due to strong electrostatic attraction. Triton X-100 outperforms CTAB and SDS in polysaccharide extraction, attributed to its higher water solubility and lower critical micelle concentration. CTAB stimulates cyanobacteria to secrete proteins, xanthohumic acid, and humic acids to maintain normal physiological cells. Additionally, the results of SEM and ion content showed that CTAB damages the cell membrane, resulting in a ∼90% increase in the release of intracellular MC-LR without cell disintegration. Ionic analyses confirm that all three surfactants alter cell membrane permeability and disrupt ionic metabolic pathways in microalgae. This study highlights the relationship between the surface charge properties of typical surfactants and the dispersion/agglomeration behavior of cyanobacteria. It provides insights into the impact mechanism of exogenous surfactants on toxic algae production in eutrophic water bodies, offering theoretical references for managing surfactant pollution and treating algae blooms.

An alternative conformation of the N-terminal loop of human dihydroorotate dehydrogenase drives binding to a potent antiproliferative agent.

Over the years, human dihydroorotate dehydrogenase (hDHODH), which is a key player in the de novo pyrimidine-biosynthesis pathway, has been targeted in the treatment of several conditions, including autoimmune disorders and acute myelogenous leukaemia, as well as in host-targeted antiviral therapy. A molecular exploration of its inhibitor-binding behaviours yielded promising candidates for innovative drug design. A detailed description of the enzymatic pharmacophore drove the decoration of well-established inhibitory scaffolds, thus gaining further in vitro and in vivo efficacy. In the present work, using X-ray crystallography, an atypical rearrangement was identified in the binding pose of a potent inhibitor characterized by a polar pyridine-based moiety (compound 18). The crystal structure shows that upon binding compound 18 the dynamics of a protein loop involved in a gating mechanism at the cofactor-binding site is modulated by the presence of three water molecules, thus fine-tuning the polarity/hydrophobicity of the binding pocket. These solvent molecules are engaged in the formation of a hydrogen-bond mesh in which one of them establishes a direct contact with the pyridine moiety of compound 18, thus paving the way for a reappraisal of the inhibition of hDHODH. Using an integrated approach, the thermodynamics of such a modulation is described by means of isothermal titration calorimetry coupled with molecular modelling. These structural insights will guide future drug design to obtain a finer Kd/logD7.4 balance and identify membrane-permeable molecules with a drug-like profile in terms of water solubility.

Reciprocal crosslink among MeCP2/BDNF /CREB signaling pinpointed in autism spectrum disorder.

Autism spectrum disorder, or individual disability (ID), is a condition characterized by complications in social interaction, restricted repetitive behavior, and difficulties in social communication. Neuquinon (NQ) possess a powerful therapeutic potential in various neurodegenerative disease. Nevertheless, contributing to NQ's low water solubility and bioavailability, its medicinal use has been constrained. Liposomes were supposed to be prospective drug-delivering agents for NQ, crossing the blood-brain barrier (BBB), and reaching the target organs. The current investigation aims to track the signaling pathways that govern NQ and liposomal neuquinon (LNQ) action in autistic models generated by ethyl formic acid. The neurotransmitters gamma amino-butyric acid (GABA), acetylcholine (ACh), and acetylcholinesterase (AChE) in addition to, the gene expressions of brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), and methyl-CpG-binding protein 2 (MeCP2) and the DNA damage COMET analysis at different time intervals of the study, were assessed. EFA in a dose of 500mg/kg BW was used to induce autism in rats, and then NQ and LNQ were administered in 10mg/kg and 2mg/kg BW, respectively. The results revealed that NQ and LNQ significantly down-regulated BDNF, GABA, and AChE; on the other hand, they up-regulated MeCP2, CREB gene expressions, and ACh action. NQ and LNQ displayed improvement in DNA damage in almost all brain regions after EFA alterations; even better results were noticed post-LNQ therapy. Therefore, it may be concluded that neuquinon and liposomal-loaded neuquinon have a therapeutic index versus EFA-induced autism in a rat model.

Recovery of Propionic Acid from Aqueous Phase using Alamine 336 in 1 - Octanol by Reactive Extraction

The by-products of carboxylic acids are useful in chemical industry, pharmaceutical industry, preservations, drug delivery towards a more economical energy efficient technology. Physical and chemical equilibria results are presented as equilibrium distribution, distribution co -efficient, extraction efficiency, loading ratio and volume percentage by varying concentrations. The distribution of propionic acid between aqueous phase and organic phase reaches equilibrium over a concentration range of 0.009 kmol/m3 – 0.055 kmol/m3 . The optimum TOA concentration is found to be 40% at which KD value for 1 - octanol is 16.7. The modified separation increases with decrease in TOA &amp; acid concentration and alamine loading with acid Z decreases with increase in alamine concentration in 1 – octanol. Optimum extraction efficiency is 43.82% for a conc. of 40% TOA at 0.2 kmol/m3.

Propagation of CO2 desaturation front in near wellbore region

Understanding the development and propagation of CO2 desaturated front is important for managing the potential of CO2 leakage via injection wells after cessation of CO2 injection. The CO2 desaturation front is the front at which oil becomes fully devoid, referred to as “desaturated”, of CO2. In this research, water injection into an oil reservoir containing CO2 is investigated to understand the effect of CO2 component transfer between brine and oil phases in the near wellbore region, as well as to monitor the development of the CO2 desaturation front. CMG-GEM compositional simulator is used to model the process. A 1D cartesian model, including homogenous properties, is utilised for the modelling. The volume of water needed to be injected to desaturate the oil from the CO2 in the vicinity of the wellbore is determined. Additionally, the velocity of the CO2 desaturation front propagation is calculated, and it is compared with the calculations of the Buckley-Leverett saturation front displacement. The study also examines how different parameters such as salinity, pressure, and temperature affect the velocity of the CO2 desaturation front, as CO2 solubility in water is influenced by these parameters. Results show that while varying the injection water salinity affects the velocity at which the CO2 desaturation front propagates, variation in the initial reservoir temperature and pressure, as well as the formation water salinity, has a minor impact, although they do alter the CO2 solubility and thus the mobilities at the front. The results also indicate that compared to the temperature front, which generally propagates at about one third of the saturation front velocity, the CO2 desaturation front in this specific case study travels at about one tenth of the saturation front velocity, so it takes much longer for the near wellbore region to completely desaturate from CO2. Other sensitivities, such as varying the residual oil saturation, affected the propagation of the CO2 desaturation front. The desaturation front travels at a slower speed at greater residual oil saturations due to the greater mass of immobilised CO2 to be displaced by this mechanism.

In Vitro Digestion-In Situ Absorption Setup Employing a Physiologically Relevant Value of the Membrane Surface Area/Volume Ratio for Evaluating Performance of Lipid-Based Formulations: A Comparative Study with an In Vitro Digestion-Permeation Model.

The aim of this study is to establish and test an in vitro digestion-in situ absorption model that can mimic in vivo drug flux by employing a physiologically relevant value of the membrane surface area (S)/volume (V) ratio for accurate prediction of oral drug absorption from lipid-based formulations (LBFs). Three different types of LBFs (Type IIIA-MC, Type IIIA-LC, and Type IV) loaded with cinnarizine (CNZ), a lipophilic weak base with borderline permeability, and a control suspension were prepared. Subsequently, a simultaneous in vitro digestion-permeation experiment was conducted using a side-by-side diffusion cell with a dialysis membrane having a low S/V value. During digestion, CNZ partially precipitated for Type IV, while it remained solubilized in the aqueous phase for Type IIIA-MC and Type IIIA-LC in the donor compartment. However, in vitro drug fluxes for Type IIIA-MC and Type IIIA-LC were lower than those for Type IV due to the reduced free fraction of CNZ in the donor compartment. In pharmacokinetic studies, a similar improvement in in vivo oral exposure relative to suspension was observed, regardless of the LBFs used. Consequently, a poor correlation was found between in vitro permeation and areas under the plasma concentration-time curve (AUCoral) (R2 = 0.087). A luminal concentration measurement study revealed that this discrepancy was attributed to the extremely high absorption rate of CNZ in the gastrointestinal tract compared to that across a dialysis membrane evaluated by the in vitro digestion-permeation model, i.e., the absorption of CNZ in vivo was completed regardless of the extent of the free fraction, owing to the rapid removal of CNZ from the intestine. Subsequently, we aimed to predict the oral absorption of CNZ from the same formulations using a model that demonstrated high drug flux by employing the physiologically relevant S/V value and rat jejunum segment as an absorption sink (for replicating in vivo intestinal permeability). Predigested formulations were injected into the rat intestinal loop, and AUCloop values were calculated from the plasma concentration-time profiles. A better correlation was found between AUCloop and AUCoral (R2 = 0.72), although AUCloop underestimated AUCoral for Type IV due to the precipitation of CNZ during the predigestion process. However, this result indicated the importance of mimicking the in vivo drug absorption rate in the predictive model. The method presented herein is valuable for the development of LBFs.